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Sample records for lowest rotational states

  1. Rotational structure of the five lowest frequency fundamental vibrational states of dimethylsulfoxide

    NASA Astrophysics Data System (ADS)

    Cuisset, Arnaud; Drumel, Marie-Aline Martin; Hindle, Francis; Mouret, Gaël; Sadovskií, Dmitrií A.

    2013-10-01

    We report on the successful extended analysis of the high-frequency (200-700 GHz) part of the gas phase (sub)mm-wave spectra of dimethylsulfoxide (DMSO). The spectrum was recorded at 100 kHz resolution using a solid state subTHz spectrometer. The five lowest energy fundamental vibrational states of DMSO with frequencies below 400 cm-1 were observed as sidebands along with the main 0←0 band. Neglecting the internal rotation of methyls, our rotational Hamiltonian reproduced the spectrum to the subMHz accuracy. We have found that the asymmetric bending state ν23 is the only low frequency fundamental vibrational state with the "anomalous" rotational structure uncovered in Cuisset et al. [1]. dmsomw 2013-09-04 15:03

  2. An Analysis of the Torsion-Rotation-Vibration Rotational Spectrum of the Lowest In-Plane Bend and First Excited Torsional State of the C(3V) Internal Rotor C2H5CN

    NASA Technical Reports Server (NTRS)

    Pearson, J. C.; Pickett, Herbert M.; Sastry, K. V. L. N.

    2000-01-01

    C2H5CN (Propionitrile or ethyl cyanide) is a well known interstellar species abundantly observed in hot cores during the onset of star formation. The onset of star formation generally results in elevated temperature, which thermally populates may low lying vibrational states such as the 206/cm in-plane bend and the 212/cm first excited torsional state in C2H5CN. Unfortunately, these two states are strongly coupled through a complex series of torsion-vibration-rotation interactions, which dominate the spectrum. In order to understand the details of these interactions and develop models capable of predicting unmeasured transitions for astronomical observations in C2H5CN and similar molecules, several thousand rotational transitions in the lowest excited in-plane bend and first excited torsional state have been recorded, assigned and analyzed. The analysis reveals very strong a- and b-type Coriolis interactions and a number of other smaller interactions and has a number of important implications for other C3V torsion-rotation-vibration systems. The relative importance and the physical origins of the coupling among the rotational, vibrational and torsional motions will be presented along with a full spectroscopic analysis and supporting astronomical observations.

  3. Rotational Spectroscopy of the Lowest Energy Conformer of 2-Cyanobutane.

    PubMed

    Müller, Holger S P; Zingsheim, Oliver; Wehres, Nadine; Grabow, Jens-Uwe; Lewen, Frank; Schlemmer, Stephan

    2017-09-28

    Isopropyl cyanide was recently detected in space as the first branched alkyl compound. Its abundance with respect to n-propyl cyanide in the Galactic center source Sagittarius B2(N2) is about 0.4. Astrochemical model calculations suggest that for the heavier homologue butyl cyanide the branched isomers dominate over the unbranched n-butyl cyanide and that 2-cyanobutane is the most abundant isomer. We have studied the rotational spectrum of 2-cyanobutane between 2 and 24 GHz using Fourier transform microwave spectroscopy and between 36 and 402 GHz employing (sub)millimeter absorption spectroscopy. Transitions of the lowest energy conformer were identified easily. Its rotational spectrum is very rich, and the quantum numbers J and Ka reach values of 111 and 73, respectively. This wealth of data yielded rotational and centrifugal distortion parameters up to tenth order, diagonal and one off-diagonal (14)N nuclear quadrupole coupling parameters, and one nuclear spin-rotation coupling parameter. We have also carried out quantum chemical calculations in part to facilitate the assignments. The molecule 2-cyanobutane was not found in the present ALMA data of Sagittarius B2(N2), but it may be found in the more sensitive data that have been completed very recently in the ALMA Cycle 4.

  4. Lowest autodetachment state of the water anion

    NASA Astrophysics Data System (ADS)

    Houfek, Karel; Čížek, Martin

    2016-05-01

    The potential energy surface of the ground state of the water anion H2O- is carefully mapped using multireference CI calculations for a large range of molecular geometries. Particular attention is paid to a consistent description of both the O-+H2 and OH-+H asymptotes and to a relative position of the anion energy to the ground state energy of the neutral molecule. The autodetachment region, where the anion state crosses to the electronic continuum is identified. The local minimum in the direction of the O- + H2 channel previously reported by Werner et al. [J. Chem. Phys. 87, 2913 (1987)] is found to be slighly off the linear geometry and is separated by a saddle from the autodetachment region. The autodetachment region is directly accessible from the OH-+H asymptote. For the molecular geometries in the autodetachment region and in its vicinity we also performed fixed-nuclei electron-molecule scattering calculations using the R-matrix method. Tuning of consistency of a description of the correlation energy in both the multireference CI and R-matrix calculations is discussed. Two models of the correlation energy within the R-matrix method that are consistent with the quantum chemistry calculations are found. Both models yield scattering quantities in a close agreement. The results of this work will allow a consistent formulation of the nonlocal resonance model of the water anion in a future publication. Contribution to the Topical Issue "Advances in Positron and Electron Scattering", edited by Paulo Limao-Vieira, Gustavo Garcia, E. Krishnakumar, James Sullivan, Hajime Tanuma and Zoran Petrovic.

  5. Ultrafast dynamics of the lowest-lying neutral states in carbon dioxide

    DOE PAGES

    Wright, Travis W.; Champenois, Elio G.; Cryan, James P.; ...

    2017-02-17

    Here, we present a study of the ultrafast dissociation dynamics of the lowest-lying electronic excited states in CO2 by using ultraviolet (UV) and extreme-ultraviolet (XUV) pulses from high-order harmonic generation. We observe two primary dissociation channels: a direct dissociation channel along the 1Πg electronically excited manifold, and a second channel which results from the mixing of electronic states. The direct dissociation channel is found to have a lifetime which is shorter than our experimental resolution, whereas the second channel has a significantly longer lifetime of nearly 200 fs. In this long-lived channel we observe a beating of the vibrational populationsmore » with a period of ~133 fs.« less

  6. Ultrafast dynamics of the lowest-lying neutral states in carbon dioxide

    NASA Astrophysics Data System (ADS)

    Wright, Travis W.; Champenois, Elio G.; Cryan, James P.; Shivaram, Niranjan; Yang, Chan-Shan; Belkacem, Ali

    2017-02-01

    We present a study of the ultrafast dissociation dynamics of the lowest-lying electronic excited states in CO2 by using ultraviolet (UV) and extreme-ultraviolet (XUV) pulses from high-order harmonic generation. We observe two primary dissociation channels: a direct dissociation channel along the Π1g electronically excited manifold, and a second channel which results from the mixing of electronic states. The direct dissociation channel is found to have a lifetime which is shorter than our experimental resolution, whereas the second channel has a significantly longer lifetime of nearly 200 fs. In this long-lived channel we observe a beating of the vibrational populations with a period of ˜133 fs.

  7. Ground and lowest-lying electronic states of CoN. A multiconfigurational study.

    PubMed

    Gobbo, João Paulo; Borin, Antonio Carlos

    2006-12-28

    The lowest-lying X1Sigma+, a3Phi, b3II, c5Delta, A1Phi, and B1II electronic states of CoN have been investigated at the ab initio MRCI and MS-CASPT2 levels, with extended atomic basis sets and inclusion of scalar relativistic effects. Among the singlet states, the A1Phi and B1II states have been described for the first time. Potential energy curves, excitation energies, spectroscopic constants, and bonding character for all states are reported. Comparison with other early transition-metal nitrides (ScN, TiN, VN, and CrN), isoelectronic (NiC) and isovalent (RhN and IrN) species has been made, besides analyzing the B1II <=> X1+ electronic transition in terms of Franck-Condon factors, Einstein coefficients, and radiative lifetimes. At both levels of theory, the following energetic order has been obtained: X1Sigma+, a3Phi, b3II, c5Delta, A1Phi, and B1II, with good agreement with experimental results. In contrast, previous DFT and MRCI calculations predicted the ground state to be the 5Delta state.

  8. Precision Spectroscopy in Cold Molecules: The Lowest Rotational Interval of He2 + and Metastable He2

    NASA Astrophysics Data System (ADS)

    Jansen, Paul; Semeria, Luca; Hofer, Laura Esteban; Scheidegger, Simon; Agner, Josef A.; Schmutz, Hansjürg; Merkt, Frédéric

    2015-09-01

    Multistage Zeeman deceleration was used to generate a slow, dense beam of translationally cold He2 molecules in the metastable a 3Σu+ state. Precision measurements of the Rydberg spectrum of these molecules at high values of the principal quantum number n have been carried out. The spin-rotational state selectivity of the Zeeman-deceleration process was exploited to reduce the spectral congestion, minimize residual Doppler shifts, resolve the Rydberg series around n =200 and assign their fine structure. The ionization energy of metastable He2 and the lowest rotational interval of the X+ 2Σu+ (ν+=0 ) ground state of 4He2+ have been determined with unprecedented precision and accuracy by Rydberg-series extrapolation. Comparison with ab initio predictions of the rotational energy level structure of 4He2+ [W.-C. Tung, M. Pavanello, and L. Adamowicz, J. Chem. Phys. 136, 104309 (2012)] enabled us to quantify the magnitude of relativistic and quantum-electrodynamics contributions to the fundamental rotational interval of He2+ .

  9. Vacuum ultraviolet spectroscopy of the lowest-lying electronic state in subcritical and supercritical water

    DOE PAGES

    Marin, Timothy W.; Janik, Ireneusz; Bartels, David M.; ...

    2017-05-17

    The nature and extent of hydrogen bonding in water has been scrutinized for decades, including how it manifests in optical properties. Here we report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of subcritical and supercritical water. For subcritical water, the spectrum redshifts considerably with increasing temperature, demonstrating the gradual breakdown of the hydrogen-bond network. Tuning the density at 381°C gives insight into the extent of hydrogen bonding in supercritical water. The known gas-phase spectrum, including its vibronic structure, is duplicated in the low-density limit. With increasing density, the spectrum blueshifts and the vibronic structure is quenched as themore » water monomer becomes electronically perturbed. Fits to the supercritical water spectra demonstrate consistency with dimer/trimer fractions calculated from the water virial equation of state and equilibrium constants. As a result, using the known water dimer interaction potential, we estimate the critical distance between molecules (ca. 4.5 Å) needed to explain the vibronic structure quenching.« less

  10. Vacuum ultraviolet spectroscopy of the lowest-lying electronic state in subcritical and supercritical water

    PubMed Central

    Marin, Timothy W.; Janik, Ireneusz; Bartels, David M.; Chipman, Daniel M.

    2017-01-01

    The nature and extent of hydrogen bonding in water has been scrutinized for decades, including how it manifests in optical properties. Here we report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of subcritical and supercritical water. For subcritical water, the spectrum redshifts considerably with increasing temperature, demonstrating the gradual breakdown of the hydrogen-bond network. Tuning the density at 381 °C gives insight into the extent of hydrogen bonding in supercritical water. The known gas-phase spectrum, including its vibronic structure, is duplicated in the low-density limit. With increasing density, the spectrum blueshifts and the vibronic structure is quenched as the water monomer becomes electronically perturbed. Fits to the supercritical water spectra demonstrate consistency with dimer/trimer fractions calculated from the water virial equation of state and equilibrium constants. Using the known water dimer interaction potential, we estimate the critical distance between molecules (ca. 4.5 Å) needed to explain the vibronic structure quenching. PMID:28513601

  11. Vacuum ultraviolet spectroscopy of the lowest-lying electronic state in subcritical and supercritical water

    NASA Astrophysics Data System (ADS)

    Marin, Timothy W.; Janik, Ireneusz; Bartels, David M.; Chipman, Daniel M.

    2017-05-01

    The nature and extent of hydrogen bonding in water has been scrutinized for decades, including how it manifests in optical properties. Here we report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of subcritical and supercritical water. For subcritical water, the spectrum redshifts considerably with increasing temperature, demonstrating the gradual breakdown of the hydrogen-bond network. Tuning the density at 381 °C gives insight into the extent of hydrogen bonding in supercritical water. The known gas-phase spectrum, including its vibronic structure, is duplicated in the low-density limit. With increasing density, the spectrum blueshifts and the vibronic structure is quenched as the water monomer becomes electronically perturbed. Fits to the supercritical water spectra demonstrate consistency with dimer/trimer fractions calculated from the water virial equation of state and equilibrium constants. Using the known water dimer interaction potential, we estimate the critical distance between molecules (ca. 4.5 Å) needed to explain the vibronic structure quenching.

  12. Rotational properties of two-component Bose gases in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Meyer, Marius; Sreejith, Ganesh Jaya; Viefers, Susanne

    2015-03-01

    We study the rotational (yrast) spectra of dilute two-component atomic Bose gases in the low angular momentum regime, assuming equal interspecies and intraspecies interaction. Our analysis employs the composite fermion (CF) approach including a pseudospin degree of freedom. While the CF approach is not a priori expected to work well in this angular momentum regime, we show that composite fermion diagonalization gives remarkably accurate approximations to low energy states in the spectra. For angular momenta 0 < L < M (where N and M denote the numbers of particles of the two species, and M >= N), we find that the CF states span the full Hilbert space and provide a convenient set of basis states which, by construction, are eigenstates of the symmetries of the Hamiltonian. Within this CF basis, we identify a subset of the basis states with the lowest Λ-level kinetic energy. Diagonalization within this significally smaller subspace constitutes a major computational simplification and provides very close approximations to ground states and a number of low-lying states within each pseudospin and angular momentum channel. This work was financially supported by the Research Council of Norway and by NORDITA.

  13. Rotational properties of two-component Bose gases in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Meyer, M. L.; Sreejith, G. J.; Viefers, S.

    2014-04-01

    We study the rotational (yrast) spectra of dilute two-component atomic Bose gases in the low angular momentum regime, assuming equal interspecies and intraspecies interaction. Our analysis employs the composite fermion (CF) approach including a pseudospin degree of freedom. While the CF approach is not a priori expected to work well in this angular momentum regime, we show that composite fermion diagonalization gives remarkably accurate approximations to low-energy states in the spectra. For angular momenta 0states span the full Hilbert space and provide a convenient set of basis states which, by construction, are eigenstates of the symmetries of the Hamiltonian. Within this CF basis, we identify a subset of the basis states with the lowest Λ-level kinetic energy. Diagonalization within this significantly smaller subspace constitutes a major computational simplification and provides very close approximations to ground states and a number of low-lying states within each pseudospin and angular momentum channel.

  14. Microwave Spectroscopic Study of NiF in the Electronic Ground and Lowest Excited States.

    PubMed

    Tanimoto, Mitsutoshi; Sakamaki, Toru; Okabayashi, Toshiaki

    2001-05-01

    The rotational spectra of NiF in the electronic ground (2)Pi state and the lowest electronically excited (2)Sigma state have been observed. The source of nickel atom was sputtering from a nickel electrode or nickel powder placed on a stainless steel electrode. The molecular constants have been determined by a least-squares analysis of the observed transition frequencies. The rapid increase in the Lambda-type splittings in the ground state reveals that the observed rotational transitions are ascribed to the spin substate (2)Pi(3/2). The rotational transitions corresponding to the other substate,(2)Pi(1/2), have not been observed. The large spin-rotation interaction constant gamma in the electronically excited (2)Sigma state is consistent with that from the electronic spectroscopy. Copyright 2001 Academic Press.

  15. Assignment of the lowest-lying THz absorption signatures in biotin and lactose monohydrate by solid-state density functional theory

    NASA Astrophysics Data System (ADS)

    Allis, D. G.; Fedor, A. M.; Korter, T. M.; Bjarnason, J. E.; Brown, E. R.

    2007-06-01

    The narrow terahertz (THz) features in crystalline biotin and lactose monohydrate observed in recent experimental studies are considered by solid-state density functional theory (DFT) calculations. The lowest-frequency THz features in both solid-state biotin and lactose monohydrate are assigned to external hindered rotational modes and not to the lowest-frequency internal modes predicted from isolated-molecule calculations. The motions of the molecules associated with these narrow THz features and the interactions between molecules in the hydrogen-bonded networks of these molecular crystals are discussed, and comparisons are made to similar studies on molecular crystals not exhibiting strong intermolecular interactions.

  16. Decomposition of formyl fluoride on the lowest triplet state surface

    NASA Astrophysics Data System (ADS)

    Sumathi, R.; Chandra, A. K.

    1992-09-01

    Decomposition of formyl fluoride on the lowest triplet potential energy hypersurface is studied using ab initio quantum chemical methods. Dissociation energies and the barrier to dissociation from the lowest triplet HFCO into H( 2S) and FCO( 2A') are reported. Results reveal that the barrier to dissociation into F( 2P) + HCO( 2A') is very high. The triatomic radical, FCO( 2A') decomposes into F( 2P) + CO( 1Σ) from the high vibrational levels of the C-F stretch.

  17. Lowest-Landau-level description of a Bose-Einstein condensate in a rapidly rotating anisotropic trap

    NASA Astrophysics Data System (ADS)

    Fetter, Alexander L.

    2007-01-01

    A rapidly rotating Bose-Einstein condensate in a symmetric two-dimensional trap can be described with the lowest Landau-level set of states. In this case, the condensate wave function ψ(x,y) is a Gaussian function of r2=x2+y2 , multiplied by an analytic function P(z) of the single complex variable z=x+iy ; the zeros of P(z) denote the positions of the vortices. Here, a similar description is used for a rapidly rotating anisotropic two-dimensional trap with arbitrary anisotropy (ωx/ωy⩽1) . The corresponding condensate wave function ψ(x,y) has the form of a complex anisotropic Gaussian with a phase proportional to xy , multiplied by an analytic function P(ζ) , where ζ∝x+iβ-y and 0⩽β-⩽1 is a real parameter that depends on the trap anisotropy and the rotation frequency. The zeros of P(ζ) again fix the locations of the vortices. Within the set of lowest Landau-level states at zero temperature, an anisotropic parabolic density profile provides an absolute minimum for the energy, with the vortex density decreasing slowly and anisotropically away from the trap center.

  18. Shedding light on a dark state: the energetically lowest quintet state of C2.

    PubMed

    Bornhauser, P; Sych, Y; Knopp, G; Gerber, T; Radi, P P

    2011-01-28

    In this work we present a deperturbation study of the d (3)Π(g), v=6 state of C(2) by double-resonant four-wave mixing spectroscopy. Accurate line positions of perturbed transitions are unambiguously assigned by intermediate level labeling. In addition, extra lines are accessible by taking advantage of the sensitivity and high dynamic range of the technique. These weak spectral features originate from nearby-lying dark states that gain transition strength through the perturbation process. The deperturbation analysis of the complex spectral region in the (6,5) and (6,4) bands of the Swan system (d(3)Π(g)-a (3)Π(u)) unveils the presence of the energetically lowest high-spin state of C(2) in the vicinity of the d (3)Π(g), v=6 state. The term energy curves of the three spin components of the d state cross the five terms of the 1 (5)Π(g) state at rotational quantum numbers N ≤ 11. The spectral complexity for transitions to the v = 6 level of d (3)Π(g) state is further enhanced by an additional perturbation at N = 19 and 21 owing to the b (3)Σ(g)(-), v=19 state. The spectroscopic characterization of both dark states is accessible by the measurement of 122 "window" levels. A global fit of the positions to a conventional Hamiltonian for a linear diatomic molecule yields accurate molecular constants for the quintet and triplet perturber states for the first time. In addition, parameters for the spin-orbit and L-uncoupling interaction between the electronic levels are determined. The detailed deperturbation study unravels major issues of the so-called high-pressure bands of C(2). The anomalous nonthermal emission initially observed by Fowler in 1910 [Mon. Not. R. Astron. Soc. 70, 484 (1910)] and later observed in numerous experimental environments are rationalized by taking into account "gateway" states, i.e., rotational levels of the d (3)Π(g), v=6 state that exhibit significant (5)Π(g) character through which all population flows from one

  19. Shedding light on a dark state: The energetically lowest quintet state of C2

    NASA Astrophysics Data System (ADS)

    Bornhauser, P.; Sych, Y.; Knopp, G.; Gerber, T.; Radi, P. P.

    2011-01-01

    In this work we present a deperturbation study of the d ^3Π _g, v=6 state of C2 by double-resonant four-wave mixing spectroscopy. Accurate line positions of perturbed transitions are unambiguously assigned by intermediate level labeling. In addition, extra lines are accessible by taking advantage of the sensitivity and high dynamic range of the technique. These weak spectral features originate from nearby-lying dark states that gain transition strength through the perturbation process. The deperturbation analysis of the complex spectral region in the (6,5) and (6,4) bands of the Swan system (d^3Π _g-a ^3Π _u) unveils the presence of the energetically lowest high-spin state of C2 in the vicinity of the d ^3Π _g, v=6 state. The term energy curves of the three spin components of the d state cross the five terms of the 1^5Π _g state at rotational quantum numbers N ⩽ 11. The spectral complexity for transitions to the v = 6 level of d ^3Π _g state is further enhanced by an additional perturbation at N = 19 and 21 owing to the b ^3Σ _g^-, v=19 state. The spectroscopic characterization of both dark states is accessible by the measurement of 122 "window" levels. A global fit of the positions to a conventional Hamiltonian for a linear diatomic molecule yields accurate molecular constants for the quintet and triplet perturber states for the first time. In addition, parameters for the spin-orbit and L-uncoupling interaction between the electronic levels are determined. The detailed deperturbation study unravels major issues of the so-called high-pressure bands of C2. The anomalous nonthermal emission initially observed by Fowler in 1910 [Mon. Not. R. Astron. Soc. 70, 484 (1910)] and later observed in numerous experimental environments are rationalized by taking into account "gateway" states, i.e., rotational levels of the d ^3Π _g, v=6 state that exhibit significant ^5Π _g character through which all population flows from one electronic state to the other.

  20. Vacuum Ultraviolet Spectroscopy of the Lowest-Lying Electronic State in Sub-Critical and Supercritical Water

    NASA Astrophysics Data System (ADS)

    Marin, Timothy W.; Janik, Ireneusz; Bartels, David M.; Chipman, Dan

    2016-06-01

    We report vacuum ultraviolet absorption spectra for the lowest-lying electronic state of high-temperature and supercritical water, where spectra were measured from room temperature up to the critical temperature, and as a function of density above the critical temperature. Spectra are seen to redshift with increasing temperature, demonstrating gradual breakdown of the hydrogen bond network. Above the critical temperature, tuning the density gives direct insight into the extent of hydrogen bonding in the supercritical regime. The known gas-phase monomer spectrum can be duplicated in the low-density limit, with negligible contribution from hydrogen bonding. With increasing density, the spectrum blue shifts as small water clusters form, increasing the number of hydrogen bonds lowering the ground-state energy. The presence of vibrational structure inherent to the lowest-density gas-phase limit spectrum gradually diminishes with increasing density, giving a reasonable measure of the extent of water monomers having unperturbed electronic structure as a function of density.

  1. Abortion rate lowest in United States since '75.

    PubMed

    1998-03-01

    The 1995 US abortion rate of 20/1000 women of reproductive age was the lowest recorded since 1975. In the period 1994-95, the birth rate decreased 1.5%, and the abortion rate decreased 4.5%. Part of the explanation for this decline can be found in the demographic make-up of US women of reproductive age. The number of women in this group has grown since 1980, but the percentage in the most fertile younger age group has declined while that in the less fertile older age group grew. The decline in births and abortions is also due to increased contraceptive usage, especially among adolescents responding to the HIV/AIDS threat. The drop in the abortion rate may also be due to the use of Norplant by adolescents who had given birth and wanted to avoid another birth. Adolescents accounted for 26% of abortions in 1985 and only 20% in 1995. More abortions are being provided at high-volume clinics, and the number of small abortion providers is decreasing. High volume clinics are associated with low complication rates, but women may have to travel further to avail themselves of abortion services. Only 12% of family practice programs nationwide offer abortion training to their residents, and this may contribute to a shortage of abortion providers.

  2. Lowest singlet excited state and spectroscopy of α-carotene

    NASA Astrophysics Data System (ADS)

    Itoh, Takao

    2011-03-01

    Emission, excitation and absorption spectra of α-carotene have been measured in solvents with different polarizabilities. It is shown that in highly-polarized solvents α-carotene emits weak fluorescence from the S 1( π, π∗) state with the fluorescence origin observed at 14 800 ± 200 cm -1. The relative S 1/S 2 fluorescence intensity ratio tends to increase with increasing solvent polarizability or decreasing the S 1-S 2 energy separation. The obtained spectroscopic data include the Raman spectrum of α-carotene along with the vibrational analyses of the Raman spectrum based on the DFT calculation at the B3LYP/6-31G(d,p) level.

  3. On the Lowest Ro-Vibrational States of Protonated Methane: Experiment and Analytical Model

    NASA Astrophysics Data System (ADS)

    Schmiedt, Hanno; Jensen, Per; Asvany, Oskar; Schlemmer, Stephan

    2016-06-01

    Protonated methane, CH_5^+, is the prototype of an extremely floppy molecule. To the best of our knowledge all barriers are surmountable in the rovibrational ground state; the large amount of zero-point vibrational energy leads to large amplitude motions for many degrees of freedom. Low resolution but broad band vibrational spectroscopy [1] revealed an extremely wide range of C-H stretching vibrations. Comparison with theoretical IR spectra supported the structural motif of a CH_3 tripod and an H_2 moiety, bound to the central carbon atom by a 3c2e bond. In a more dynamic picture the five protons surround the central carbon atom without significant restrictions on the H-C-H bending or H_n-C torsional motions. The large-amplitude internal motions preclude a simple theoretical description of the type possible for more conventional molecules, such as the related spherical-top methane molecule. Recent high-resolution ro-vibrational spectra obtained in cold ion trap experiments [2] show that the observed CH_5^+ transitions belong to a very well-defined energy level scheme describing the lowest rotational and vibrational states of this enigmatic molecule. Here we analyse the experimental ground state combination differences and associate them with the motional states of CH_5^+ allowed by Fermi-Dirac statistics. A model Hamiltonian for unrestricted internal rotations in CH_5^+ yields a simple analytical expression for the energy eigenvalues, expressed in terms of new quantum numbers describing the free internal rotation. These results are compared to the experimental combination differences and the validity of the model will be discussed together with the underlying assumptions. [1] O. Asvany, P. Kumar, I. Hegemann, B. Redlich, S. Schlemmer and D. Marx, Science 309, (2005) 1219-1222 [2] O. Asvany, K.M.T. Yamada, S. Brünken, A. Potapov, S. Schlemmer, Science 347 (2015) 1346-1349

  4. Rovibrational Interactions in the Ground and Two Lowest Excited Vibrational States of Methoxy Isocyanate

    NASA Astrophysics Data System (ADS)

    Pienkina, A.; Margulès, L.; Motiyenko, R. A.; Guillemin, J.-C.

    2017-06-01

    Recent detection of methyl isocyanate (CH_3NCO) in the Orion, towards Sgr B2(N) and on the surface of the comet 67P/Churyumov-Gerasimenko motivated us to study another isocyanate, methoxy isocyanate (CH_3ONCO) as a possible candidate molecule for searches in the interstellar clouds. Neither identification or laboratory rotational spectra of CH_3ONCO has been reported up to now. Methoxy isocyanate was synthesized by the flash vacuum pyrolysis of N-Methoxycarbonyl-O-methyl-hydroxylamine (MeOC(O)NHOMe) at a temperature of 800 K. Experimental spectrum of CH_3ONCO was recorded in situ in the millimeter-wave range (75-105 GHz and 150-330 GHz) using Lille's fast-scan fully solid-state DDS spectrometer. The recorded spectrum is strongly perturbed due to the interaction between the overall rotation and the skeletal torsion. Perturbations affect even rotational transitions with low K_a levels of the ground vibrational state, appearing in shifting frequency predictions and intensities distortions of the lines. The interactions are significant due to the relatively small vibrational energy difference (≈50 \\wn) between the states and different representations of the C_s symmetry point group for the ground (A'), ν_{18}=1 (A'') and ν_{18}=2 (A') vibrational states, thus leading to a "ladder" of multiple resonances by means of a-, and b-type Coriolis coupling. The global fit analysis of the rotational spectrum of methoxy isocyanate using Coriolis coupling terms in the ground and two lowest vibrational states (ν_{18}=1 and ν_{18}=2) will be presented. J. Cernicharo, N. Marcelino, E. Roueff et al. 2012, ApJ, 759, L43 D. T. Halfen, V. V. Ilyushin, & L. M. Ziurys, 2015, ApJ, 812, L5 F. Goesmann, H. Rosenbauer, J. H. Bredehöft et al. 2015, Science, 349.6247, aab0689 This work was funded by the French ANR under the Contract No. ANR-13-BS05-0008-02 IMOLABS.

  5. Far infrared spectrum of Methanol-D2 in the lowest torsional state (e0)

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Indra

    2016-03-01

    The infrared (IR) and far infrared (FIR) absorption spectra have been measured for the Methanol-D1 and D2 species in the wave number range of 20-1200 cm-1 at the Justus Liebig Universität in Giessen, Germany using a Brüker Fourier Transform spectrometer at a resolution of 0.002 cm-1. The spectra looked very complicated but analyses were possible for the lower lying states. At higher wave number regions spectra of few vibrational fundamental modes were visible. In this communication, the details of the assignments and analyses of the lowest lying internal rotational state (e0) for Methanol-D2 are reported. A catalog of about 900 assigned spectral lines has been prepared and is made available from the author to conserve space. As application of this work, it was possible to assign some optically pumped FIR laser lines to quantum states. The results should be useful for "radio astronomers" and in the field of optically pumped FIR and Sub-millimeter Wave (SMMW) lasers which are used in Tokamaks for plasma diagnostics and as local oscillators in radio detection from space.

  6. Millimeter-wave and Submillimeter-wave Spectra of Aminoacetonitrile in the Three Lowest Vibrational Excited States

    NASA Astrophysics Data System (ADS)

    Degli Esposti, Claudio; Dore, Luca; Melosso, Mattia; Kobayashi, Kaori; Fujita, Chiho; Ozeki, Hiroyuki

    2017-06-01

    It is important to study possible precursors of amino acids such as glycine to enable future searches in interstellar space. Aminoacetonitrile (NH2CH2CN) is one of the most feasible molecules for this purpose. This molecule was already detected toward Sgr B2(N). Aminoacetonitrile has a few low-lying vibrational excited states, and transitions within these states may be found in space. In this study, the pure-rotational transitions in the three lowest vibrational states in the 80-450 GHz range have been assigned and analyzed. It was found to be very important to include Coriolis coupling between the two lowest vibrational fundamentals, while the third one was unperturbed. The partition function was evaluated considering these new results.

  7. A Description of Vibrational Modes in Hexaphyrins: Understanding the Aromaticity Reversal in the Lowest Triplet State.

    PubMed

    Sung, Young Mo; Oh, Juwon; Naoda, Koji; Lee, Taegon; Kim, Woojae; Lim, Manho; Osuka, Atsuhiro; Kim, Dongho

    2016-09-19

    Aromaticity reversal in the lowest triplet state, or Baird's rule, has been postulated for the past few decades. Despite numerous theoretical works on aromaticity reversal, experimental study is still at a rudimentary stage. Herein, we investigate the aromaticity reversal in the lowest excited triplet state using a comparable set of [26]- and [28]hexaphyrins by femtosecond time-resolved infrared (IR) spectroscopy. Compared to the relatively simple IR spectra of [26]bis(rhodium) hexaphyrin (R26H), those of [28]bis(rhodium) hexaphyrin (R28H) show complex IR spectra the region for the stretching modes of conjugated rings. Whereas time-resolved IR spectra of R26H in the excited triplet state are dominated by excited state IR absorption peaks, while those of R28H largely show ground state IR bleaching peaks, reflecting the aromaticity reversal in the lowest triplet state. These contrasting IR spectral features serve as new experimental aromaticity indices for Baird's rule.

  8. Structures of the Lowest Energy Nonamer and Decamer Water Clusters from Chirped-Pulse Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Perez, Cristobal; Pate, Brooks H.; Kisiel, Zbigniew; Temelso, Berhane; Shields, George C.

    2013-06-01

    In the breakthrough paper reporting observation and analysis of pure rotational spectra of the hexamer, heptamer and nonamer water clusters only one nonamer species was identified. The advances in this experiment, as described in the previous talk, allowed identification, among others, of five different nonamer, (H_2O)_9, conformers and of four different decamer, (H_2O)_{10}, conformers. Analysis of ^{18}O enriched spectra resulted in determination of oxygen framework geometries for three of the water nonamers and two of the water decamers. Determination of experimental geometries proved considerably more challenging than for the lighter clusters since isotopic changes to moments of inertia are proportionally smaller, and there are multiple instances of near-zero principal coordinates. There are also more indications of the effect of internal motions. These problems have been overcome by careful application of r_s and least-squares r_m techniques in concert with ab initio calculations so that it was possible to match the experimental and theoretical geometries unambiguously. The precise oxygen framework geometries obtained from chirped-pulse spectroscopy for water clusters ranging in size from the hexamer to the decamer allow, for the first time, to identify some common features of the underlying hydrogen bonding from direct experimental evidence. C. Perez, M. T. Muckle, D. P. Zaleski, N. A. Seifert, B. Temelso, G. C. Shields, Z. Kisiel, and B. H. Pate, Science {336}, 897 (2012).

  9. Quantum chemical study on the population of the lowest triplet state of psoralen

    NASA Astrophysics Data System (ADS)

    Serrano-Pérez, Juan José; Merchán, Manuela; Serrano-Andrés, Luis

    2007-01-01

    The efficient population of the low-lying triplet ππ * state of psoralen is studied with the quantum chemical CASPT2 method. Minima, singlet-triplet crossings, conical intersections, and reaction paths on the low-lying singlet and triplet states hypersurfaces of the system have been computed together with electronic energy gaps and spin-orbit coupling terms. A mechanism is proposed, favorable in the gas phase, for efficient deactivation of the initially populated singlet excited ππ * state, starting with an intersystem crossing with an nπ * triplet state and evolving via a conical intersection toward the final lowest-lying ππ * triplet state, protagonist of the reactivity of psoralen.

  10. Zero-field-splitting in the lowest triplet state of C 60

    NASA Astrophysics Data System (ADS)

    Surján, P. R.; Németh, K.; Bennati, M.; Grupp, A.; Mehring, M.

    1996-03-01

    Zero-field-splitting parameters D and E for the fullerene C 60 in its Jahn-Teller distorted triplet state were calculated and compared to recent experimental results. The E value vanishes due to symmetry, while we obtained a non-zero D value of D = -0.009 cm -1 in the D 5d distorted lowest triplet state. The absolute value of D is in good agreement with experimental data, which suggests that the sign of D is negative.

  11. Can the lowest two electronic states of Si 2 be ordered?

    NASA Astrophysics Data System (ADS)

    Lüthi, H. P.; McLean, A. D.

    1987-04-01

    Second-order configuration interaction (SOCI) calculations on Si 2 and C 2 in their lowest 3Σ -g and 3Π u, states, combined with experimental data for C 2, lead to a prediction of a near certain 3Σ g-Si 2 ground state with Te = 180 ± 200 cm -1. Enough computed information is now available to guide an experimental search for the bands in the 3Σ -g to 3Π u electronic transition.

  12. Ultrafast internal conversion of excited cytosine via the lowest pipi electronic singlet state.

    PubMed

    Merchán, Manuela; Serrano-Andrés, Luis

    2003-07-09

    Computational evidence at the CASPT2 level supports that the lowest excited state pipi* contributes to the S1/S0 crossing responsible for the ultrafast decay of singlet excited cytosine. The computed radiative lifetime, 33 ns, is consistent with the experimentally derived value, 40 ns. The nOpi* state does not play a direct role in the rapid repopulation of the ground state; it is involved in a S2/S1 crossing. Alternative mechanisms through excited states pisigma* or nNpi* are not competitive in cytosine.

  13. Nature of the lowest excited states of neutral polyenyl radicals and polyene radical cations

    NASA Astrophysics Data System (ADS)

    Starcke, Jan Hendrik; Wormit, Michael; Dreuw, Andreas

    2009-10-01

    Due to the close relation of the polyenyl radicals C2n+1H2n+3• and polyene radical cations C2nH2n+2•+ to the neutral linear polyenes, one may suspect their excited states to possess substantial double excitation character, similar to the famous S1 state of neutral polyenes and thus to be equally problematic for simple excited state theories. Using the recently developed unrestricted algebraic-diagrammatic construction scheme of second order perturbation theory and the equation-of-motion coupled-cluster method, the vertical excitation energies, their corresponding oscillator strengths, and the nature of the wave functions of the lowest excited electronic states of the radicals are calculated and analyzed in detail. For the polyenyl radicals two one-photon allowed states are found as D1 and D4 states, with two symmetry-forbidden D2 and D3 states in between, while in the polyene radical cations D1 and D2 are allowed and D3 is forbidden. The order of the states is conserved with increasing chain length. It is found that all low-lying excited states exhibit a significant but similar amount of doubly excited configuration in their wave functions of 15%-20%. Using extrapolation, predictions for the excitation energies of the five lowest excited states of the polyene radical cations are made for longer chain lengths.

  14. Nuclear electric dipole moments for the lowest 1/2+ states in Xe and Ba isotopes

    NASA Astrophysics Data System (ADS)

    Yoshinaga, N.; Higashiyama, K.; Arai, R.; Teruya, E.

    2014-04-01

    The electric dipole moments for the lowest 1/2+ states of Xe and Ba isotopes are calculated in terms of the nuclear shell model, which includes two-body nucleon interactions violating parity and time-reversal invariance. Using the wave functions thus obtained, the nuclear electric dipole moments arising from the intrinsic nucleon electric dipole moments and also from asymmetric charge distribution are calculated. The upper limits for the nuclear electric dipole moments of Xe and Ba isotopes are estimated.

  15. Phosphorescence, ODMR and ODNQR investigation of the distorted lowest excited triplet state of sym-tetrachloropyrazine

    NASA Astrophysics Data System (ADS)

    von Borczyskowski, C.

    The lowest excited triplet state of sym-tetrachloropyrazine has been investigated at 1·5 K in single crystals of sym-tetramethylbenzene (TMB) and symtetrachlorobenzene (TCB). By analysis of the chlorine and nitrogen hyperfine interaction a 3ππ* state with B2u symmetry has been identified which is contrary to the B1u symmetry of TCB. The large difference between chlorine quadrupole resonance transitions in the singlet ground and excited triplet state of 2·75 MHz (TCB) and 3·3 MHz (TMB) suggests an out-of-plane position of chlorine nuclei in the triplet state. Analysis of the vibronic structure of the phosphorescence reveals that vibronic coupling to an energetically close lying 3nπ* state is, in comparison with other pyrazines, greatly reduced.

  16. Fully Relativistic Calculations on the Potential Energy Surfaces of the Lowest 23 States of Molecular Chlorine

    SciTech Connect

    Luiz Guilherme M. de Macedo; de Jong, Wibe A.

    2008-01-24

    The electronic structure and spectroscopic properties (Re, ωexe, βe, Te ) of the ground state and the 22 lowest excited states of chlorine molecule were studied within a four component relativistic framework using the MOLFDIR program package. The potential energy curves of all possible 23 covalent states were calculated using relativistic complete open shell configuration interaction (COSCI) approach. In addition, four component multi-reference configuration interaction with singles and doubles excitations (MRCISD) calculations were performed in order to infer the effects due to dynamical correlation in vertical excitations. The calculated properties are in good agreement with the available experimental data.

  17. How much double excitation character do the lowest excited states of linear polyenes have?

    NASA Astrophysics Data System (ADS)

    Starcke, Jan Hendrik; Wormit, Michael; Schirmer, Jochen; Dreuw, Andreas

    2006-10-01

    Doubly excited states play important roles in the low-energy region of the optical spectra of polyenes and their investigation has been subject of theoretical and experimental studies for more than 30 years now and still is in the focus of ongoing research. In this work, we address the question why doubly excited states play a role in the low-energy region of the optical spectrum of molecular systems at all, since from a naive point of view one would expect their excitation energy approximately twice as large as the one of the corresponding single excitation. Furthermore, we show that extended-ADC(2) is well suited for the balanced calculation of the low-lying excited 21Ag-, 11Bu- and 11Bu+ states of long all- trans polyenes, which are known to possess substantial double excitation character. A careful re-investigation of the performance of TDDFT calculations for these states reveals that the previously reported good performance for the 21Ag- state relies heavily on fortuitous cancellation of errors. Finally, the title question is answered such that for short polyenes the lowest excited 21Ag- and 11Bu- states can clearly be classified as doubly excited, whereas the 11Ag- ground state is essentially represented by the (ground-state) HF determinant. For longer polyenes, in addition to increasing double excitation contributions in the 21Ag- and 11Bu- states, the ground state itself aquires substantial double excitation character (45% in C 22H 24), so that the transition from the ground state to these excited states should not be addressed as the excitation of two electrons relative to the 11Ag- ground state.

  18. Skyrme random-phase-approximation description of lowest Kπ=2γ+ states in axially deformed nuclei

    NASA Astrophysics Data System (ADS)

    Nesterenko, V. O.; Kartavenko, V. G.; Kleinig, W.; Kvasil, J.; Repko, A.; Jolos, R. V.; Reinhard, P.-G.

    2016-03-01

    The lowest quadrupole γ -vibrational Kπ=2+ states in axially deformed rare-earth (Nd, Sm, Gd, Dy, Er, Yb, Hf, W) and actinide (U) nuclei are systematically investigated within the separable random-phase-approximation (SRPA) based on the Skyrme functional. The energies Eγ and reduced transition probabilities B (E 2 ) of 2γ+ states are calculated with the Skyrme forces SV-bas and SkM*. The energies of two-quasiparticle configurations forming the SRPA basis are corrected by using the pairing blocking effect. This results in a systematic downshift of Eγ by 0.3-0.5 MeV and thus in a better agreement with the experiment, especially in Sm, Gd, Dy, Hf, and W regions. For other isotopic chains, a noticeable overestimation of Eγ and too weak collectivity of 2γ+ states still persist. It is shown that domains of nuclei with low and high 2γ+ collectivity are related to the structure of the lowest two-quasiparticle states and conservation of the Nilsson selection rules. The description of 2γ+ states with SV-bas and SkM* is similar in light rare-earth nuclei but deviates in heavier nuclei. However SV-bas much better reproduces the quadrupole deformation and energy of the isoscalar giant quadrupole resonance. The accuracy of SRPA is justified by comparison with exact RPA. The calculations suggest that a further development of the self-consistent calculation schemes is needed for a systematic satisfactory description of the 2γ+ states.

  19. Conformational analysis of acetamide in the ground and lowest excited electronic states

    NASA Astrophysics Data System (ADS)

    Tukachev, N. V.; Bataev, V. A.; Godunov, I. A.

    2017-05-01

    For acetamide molecule (CH3CONH2) in the ground (S0) and lowest excited singlet (S1) and triplet (T1) electronic states calculations of equilibrium geometry parameters, harmonic vibrational frequencies and barriers to conformational transitions (also conformer energy differences in excited states) using following ab initio methods: MP2, CCSD(T), CASSCF, CASPT2 and MRCI were performed. One-, two- and three-dimensional potential energy surface (PES) sections by different large amplitude motions (LAM) coordinates were calculated by means of MP2/aug-cc-pVTZ (S0) and CASPT2/cc-pVTZ (S1, T1). As a result of electronic excitation, both CCON and CNH2 fragments become pyramidal. On 2D PES sections by torsion (CN) and inversion coordinates there are six minima forming three pairs of enantiomers. Using PES sections different anharmonic vibrational problems were solved and the frequencies of large amplitude vibrations were estimated.

  20. Time-resolved infrared spectroscopy of the lowest triplet state of thymine and thymidine

    PubMed Central

    Hare, Patrick M.; Middleton, Chris T.; Mertel, Kristin I.

    2008-01-01

    Vibrational spectra of the lowest energy triplet states of thymine and its 2’-deoxyribonucleoside, thymidine, are reported for the first time. Time-resolved infrared (TRIR) difference spectra were recorded over seven decades of time from 300 fs – 3 µs using femtosecond and nanosecond pump-probe techniques. The carbonyl stretch bands in the triplet state are seen at 1603 and ~1700 cm−1 in room-temperature acetonitrile-d3 solution. These bands and additional ones observed between 1300 and 1450 cm−1 are quenched by dissolved oxygen on a nanosecond time scale. Density-functional calculations accurately predict the difference spectrum between triplet and singlet IR absorption cross sections, confirming the peak assignments and elucidating the nature of the vibrational modes. In the triplet state, the C4=O carbonyl exhibits substantial single-bond character, explaining the large (~70 cm−1) red shift in this vibration, relative to the singlet ground state. Femtosecond TRIR measurements unambiguously demonstrate that the triplet state is fully formed within the first 10 ps after excitation, ruling out a relaxed 1nπ* state as the triplet precursor. PMID:19936322

  1. Time-resolved infrared spectroscopy of the lowest triplet state of thymine and thymidine

    NASA Astrophysics Data System (ADS)

    Hare, Patrick M.; Middleton, Chris T.; Mertel, Kristin I.; Herbert, John M.; Kohler, Bern

    2008-05-01

    Vibrational spectra of the lowest energy triplet states of thymine and its 2'-deoxyribonucleoside, thymidine, are reported for the first time. Time-resolved infrared (TRIR) difference spectra were recorded over seven decades of time from 300 fs to 3 μs using femtosecond and nanosecond pump-probe techniques. The carbonyl stretch bands in the triplet state are seen at 1603 and ˜1700 cm -1 in room-temperature acetonitrile- d3 solution. These bands and additional ones observed between 1300 and 1450 cm -1 are quenched by dissolved oxygen on a nanosecond time scale. Density-functional calculations accurately predict the difference spectrum between triplet and singlet IR absorption cross sections, confirming the peak assignments and elucidating the nature of the vibrational modes. In the triplet state, the C4 dbnd O carbonyl exhibits substantial single-bond character, explaining the large (˜70 cm -1) red shift in this vibration, relative to the singlet ground state. Femtosecond TRIR measurements unambiguously demonstrate that the triplet state is fully formed within the first 10 ps after excitation, ruling out a relaxed 1nπ ∗ state as the triplet precursor.

  2. Multi-mode vibronic interactions in the five lowest electronic states of the fluorobenzene radical cation

    NASA Astrophysics Data System (ADS)

    Bâldea, Ioan; Franz, Jan; Szalay, Péter G.; Köppel, Horst

    2006-10-01

    The multi-mode vibronic interactions between the five lowest electronic states of the fluorobenzene radical cation are investigated theoretically, based on ab initio electronic structure data, and employing the linear vibronic coupling model. Low-energy conical intersections, and strong vibronic couplings are found to prevail within the set of X˜-A˜ and B˜-C˜-D˜ cationic states, while the interactions between these two sets of states are found to be rather weak (owing to high-energy conical intersections). The overall intensity distribution of the experimental photoelectron spectrum, as well as the line positions observed in the MATI spectrum, are well reproduced. The vibronic interactions in the X˜-A˜ states are found to be a replica of the multi-mode dynamical Jahn-Teller effect in the parent system, the XE ground state of the benzene radical cation. Ultrafast internal conversion processes within the electronic manifolds in question demonstrate the strength of the nonadiabatic coupling effects and complement the analogous findings for the electronic spectra. The implications for the fluorescence dynamics of the fluorobenzene radical cation are discussed.

  3. Optical transitions from the lowest to higher exciton and biexciton Rydberg states in CuCl

    NASA Astrophysics Data System (ADS)

    Miyajima, K.; Sakaniwa, K.; Sugawara, M.

    2016-11-01

    We measured the optical transitions due to the internal energy levels of an exciton and biexciton in a CuCl single crystal using pump-probe spectroscopy. The transient absorption bands due to the transitions from the 1 s to 2 p and from the 1 s to 3 p exciton states were observed at 3 K, which is consistent with their reported energies. Simultaneously, the transient absorption peak due to the biexciton was observed, which corresponds to a transition from the lowest state (composed of two 1 s excitons) to higher states (composed of 1 s and 2 p excitons). The value of the observed biexciton peak energy was reasonable considering the hydrogen molecule orbitals and the electron-to-hole effective mass ratio. In addition, the transient absorption peaks were broadened at 77 K, because of the increase in the homogeneous width of the 2 p exciton state. The transient absorption spectrum was almost completely determined by this width. Our findings are of importance with regard to the optical phenomena in the infrared region related to the quantum coherence of excitons and biexcitons in semiconductors.

  4. Radiative deactivation of the lowest triplet state of dibenzo- p-dioxine

    NASA Astrophysics Data System (ADS)

    Gastilovich, E. A.; Korol'Kova, N. V.; Klimenko, V. G.; Serov, S. A.

    2002-08-01

    A theoretical evaluation of the dipole moments of vibronic transitions (which are governed by vibronic spin-orbit interactions) was carried out for dibenzo- p-dioxin molecules. On the basis of the comparison of the obtained results with the data on the distribution of line intensities in a fine-structure phosphorescence spectrum of dibenzo- p-dioxin at 4.2 K, it is inferred that radiative deactivation of the lowest triplet state T 1 (ππ*) occurs from one of the triplet sublevels. For the molecules of dibenzo- p-dioxin and one of the isomers of tetrachlorodibenzo- p-dioxin, the effect of the form of vibrational modes and individual constants of the spin-orbit coupling in O and Cl atoms on vibronic spin-orbit interactions is discussed.

  5. Ab initio study of the three lowest-lying (X 1Σ+, 3Σ+, and 1Σ+) electronic states of AgF

    NASA Astrophysics Data System (ADS)

    Ramirez-Solis, A.; Schamps, J.

    1995-03-01

    Ab-initio pseudopotential two-configuration self-consistent field followed by extensive variational and perturbational second order Møller-Plesset multireference configuration interaction calculations using localized molecular orbitals were performed to characterize the structure and adiabatic potential energy curves of the three lowest (X 1Σ+, 3Σ+, and 1Σ+) purely electronic states of the AgF molecule. Spin-orbit interactions were introduced semiempirically in a second step. The very strong coupling of the neutral Ag(4d105s1)F(2s22p5) and ionic Ag+(4d95s1)F-(2s22p6) configurations at rather short internuclear distance for both excited 3,1Σ+ states is responsible for the appearance of very shallow minima, thus leading to a limited number of stable vibrational levels for these excited states as suggested previously for the AO+ state. In contrast with the CuF molecule, where only the ionic configuration Cu+(3,1D)F-(1S) is present in the 3,1Σ+ states, this coupling of ionic and neutral structures in AgF is explained by the relative positions of the valence orbital energies of the neutral Cu and Ag atoms with respect to the 2p level of the halogen atom. These results lead to the assignment of the observed AO+-X 1Σ+ transition as a 1Σ+-1Σ+ type transition. The very recently observed aΩ1 and A'Ω1 states are shown to be, respectively, the Ω=O- and Ω=1 spin-orbit components of the 3Σ+ state, which justifies the relabeling of aΩ1 into a aΩO-. The calculated spin-orbit-induced splitting between these two components is in excellent agreement with the observed one after reconsidering spectroscopic data. For all these states the calculated spectroscopic constants are in good agreement with available experimental data. The fourth experimental state, BO+, is probably not correlated with the 3Π valence state as previously suggested but it could rather correspond to a Rydberg ionic state involving the Ag+(4d95p)F-(2s22p6) structure.

  6. Isotope effects of ground and lowest lying vibrational states of H 3 - x D x O2 - complexes

    NASA Astrophysics Data System (ADS)

    Ansari, Narjes; Meyer, Hans-Dieter

    2016-02-01

    Isotope effects of the H 3 O2 - anion are investigated. For this, the 24 lowest excited vibrational states of the H 3 - x D x O2 - complexes, with x = 0-3, are computed using two different Hamiltonians, namely, a 7D reduced-dimensionality one with a numerical representation of the kinetic energy operator (KEO) and a 9D full-dimensionality Hamiltonian with an exact analytic KEO. The computations are carried out with the multiconfiguration time-dependent Hartree method. The obtained results show that bridge and terminal H-D exchange cause a variation in energy with or without a rearrangement of states. A clear rearrangement of fundamental modes is observed in bridge H-D exchange of the H 3 O2 - complex, where the frequency of bridge hydrogen stretching (z) is strongly lowered by substitution. The isotope effects show that rotation (ϕ), rocking (u1 + u2), wagging (u1 - u2), and O-O stretch (R) modes are sensitive to terminal H-D exchange, while the bridge-atom bending (x,y) and stretch (z) modes are sensitive to bridge H-D exchange. An influence coefficient, which measures the influence of an excitation of one mode on the various 1D reduced densities, is defined and analyzed in detail. It is shown that the D 3 O2 - complex is more strongly correlated or coupled than the other isotopologues.

  7. Isotope effects of ground and lowest lying vibrational states of H(3-x)D(x)O2(-) complexes.

    PubMed

    Ansari, Narjes; Meyer, Hans-Dieter

    2016-02-07

    Isotope effects of the H3O2(-) anion are investigated. For this, the 24 lowest excited vibrational states of the H(3-x)D(x)O2(-) complexes, with x = 0-3, are computed using two different Hamiltonians, namely, a 7D reduced-dimensionality one with a numerical representation of the kinetic energy operator (KEO) and a 9D full-dimensionality Hamiltonian with an exact analytic KEO. The computations are carried out with the multiconfiguration time-dependent Hartree method. The obtained results show that bridge and terminal H-D exchange cause a variation in energy with or without a rearrangement of states. A clear rearrangement of fundamental modes is observed in bridge H-D exchange of the H3O2(-) complex, where the frequency of bridge hydrogen stretching (z) is strongly lowered by substitution. The isotope effects show that rotation (ϕ), rocking (u1 + u2), wagging (u1 - u2), and O-O stretch (R) modes are sensitive to terminal H-D exchange, while the bridge-atom bending (x,y) and stretch (z) modes are sensitive to bridge H-D exchange. An influence coefficient, which measures the influence of an excitation of one mode on the various 1D reduced densities, is defined and analyzed in detail. It is shown that the D3O2(-) complex is more strongly correlated or coupled than the other isotopologues.

  8. Valence and Ionic Lowest-Lying Electronic States of Isobutyl Formate Studied by High-Resolution Vacuum Ultraviolet Photoabsorption, Photoelectron Spectroscopy, and Ab Initio Calculations.

    PubMed

    Śmiałek, M A; Łabuda, M; Guthmuller, J; Hoffmann, S V; Jones, N C; MacDonald, M A; Zuin, L; Mason, N J; Limão-Vieira, P

    2015-08-13

    The highest resolution vacuum ultraviolet photoabsorption spectrum of isobutyl formate, C5H10O2, yet reported is presented over the energy range 4.5-10.7 eV (275.5-118.0 nm) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series observed in the photoabsorption spectrum have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of isobutyl formate and are compared with a newly recorded photoelectron spectrum (from 9.0 to 27.0 eV). The value of the first ionization energy was determined to be 10.508 eV (adiabatic) and 10.837 eV (vertical). New vibrational structure is observed in the first photoelectron band, predominantly resulting from C-O and C═O stretches of the molecule. The photoabsorption cross sections have been used to calculate the photolysis lifetime of isobutyl formate in the upper stratosphere (20-50 km), indicating that the hydroxyl radical processes will be the main loss process for isobutyl formate.

  9. Deuterium isotope effects on the zero-field splittings of the lowest triplet state of benzaldehyde derivatives

    NASA Astrophysics Data System (ADS)

    Neugebauer, S. M.; Tinti, D. S.

    1993-08-01

    The zero-field splitting parameters, D and E, in the lowest triplet state of p-chlorobenzaldehyde, p-methylbenzaldehyde, and their d1 isotopes (aldehyde proton), are determined by ODMR measurements. The results show that the sign of the isotopic change in D reflects the orbital character of the lowest triplet state. The magnitude of D increases in the d1 isotope of both guests in p-dimethoxybenzene where the lowest guest triplet state is 3nπ*, but it decreases in p-xylene where the stae is 3ππ*. The results are interpreted in terms of the spin—orbit interactions between the nearby 3nπ* and 3ππ* states and the isotopic changes in the zero-point energies of the states.

  10. An ab initio study on the four electronically lowest-lying states of CH 2 using the state-averaged complete active space second-order configuration interaction method

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Yukio; Schaefer, Henry F., III

    1997-12-01

    Four electronically lowest-lying ( X˜ 3B 1, ã 1A 1, b˜ 1B 1, and c˜ 1A 1) states of CH 2 have been investigated systematically using ab initio electronic structure theory. Complete active space (CAS) self-consistent-field (SCF) second-order configuration interaction (SOCI) and state-averaged (SA) CASSCF-SOCI levels of theory have been employed. The CASSCF reference wave function was constructed by minimizing the total energy of a specified state, while the SACASSCF reference wave function was obtained by minimizing the equally weighted total energy of the four ( X˜ 3B 1, ã 1A 1, b˜ 1B 1, and c˜ 1A 1) states. The third excited state ( c˜ 1A 1 or 2 1A 1) is of particular theoretical interest because it is represented by the second root of CASSCF and SOCI Hamiltonian matrices. Theoretical treatments of states not the lowest of their symmetry require special attention due to their tendency of variational collapse to the lower-lying state(s). For these four lowest-lying states total energies and physical properties including dipole moments, harmonic vibrational frequencies, and associated infrared (IR) intensities were determined and compared with the results from the configuration interaction with single and double excitations (CISD) method and available experimental values. The CASSCF-SOCI method should provide the most reliable energetics and physical properties in the present study owing to its fully variational nature in the molecular orbital (MO) and CI spaces for a given state. It is demonstrated that the SACASSCF-SOCI wave functions produce results which are quite consistent with those from the CASSCF-SOCI method. Thus significantly increased application of the SACASSCF-SOCI method to the excited states of a wide variety of molecular systems is expected.

  11. Sub-millimeter wave spectroscopy of the C 3H radical: Ro-vibrational transitions from ground to the lowest bending state

    NASA Astrophysics Data System (ADS)

    Caris, M.; Giesen, T. F.; Duan, C.; Müller, H. S. P.; Schlemmer, S.; Yamada, K. M. T.

    2009-02-01

    Linear C 3H in its (X 2Π) electronic ground state possesses strong Renner-Teller coupling in the two lowest bending modes, ν4 and ν5. The 2Σμ level of the v4 = 1 bending mode is shifted towards lower energies and is supposed to lie only 20.3 cm -1 above the ground state [S. Yamamoto, S. Saito, H. Suzuki, S. Deguchi, N. Kaifu, S. Ishikawa, M. Ohishi, Astrophys. J. 348 (1990) 363]. In the present study, first measurements of ro-vibrational transitions from the 2Π3/2 ground state to the 2Σμ lowest vibrational state were performed using a Terahertz spectrometer equipped with a supersonic jet nozzle. Rotational levels of the 2Π3/2 and v4 = 1( 2Σμ) state are close in energy and a crossing of the rotational energy ladders occurs between J = 24.5 and 25.5. A strong vibronic coupling leads to a significant intensity enhancement of 2Π3/2 - 2Σμ ro-vibrational transitions. The search for ro-vibrational transitions was facilitated by measurements on pure rotational transitions in the 2Π1/2, 2Π3/2 and v4 = 1( 2Σμ) states, substantially extending the former data set published by Yamamoto et al. Data analysis yields an accurate value for the v4 = 1( 2Σμ) energy level which has been found to lie 609.9771(42) GHz or 20.34664(14) cm -1 above the 2Π ground state. Furthermore, the value of the vibronic coupling constant β has been improved significantly and determined as 1231.77(51) MHz. The new set of spectroscopic parameters obtained in the present study permits very reliable frequency predictions into the Terahertz region.

  12. High resolution study of the six lowest doubly excited vibrational states of PH 2D

    NASA Astrophysics Data System (ADS)

    Leroy, C.; Ulenikov, O. N.; Bekhtereva, E. S.; Onopenko, G. A.; Chudinova, T. D.

    2005-12-01

    The five lowest doubly excited deformational vibrational bands ν4 + ν6, 2 ν6, ν3 + ν4, ν3 + ν6, and 2 ν3 of PH 2D have been recorded for the first time using a Bruker 120 HR interferometer with a resolution 0.0033 cm -1 and analysed. Some transitions belonging to a very weak band 2 ν4 have been also assigned. From the fit 24 and 86, respectively, diagonal and resonance interaction parameters were obtained which reproduce 1089 upper energy levels obtained from more than 4600 assigned transitions with the rms deviation of 0.00059 cm -1.

  13. Electronic structure and chemical bonding in the lowest electronic states of TcN.

    PubMed

    Borin, Antonio Carlos; Gobbo, João Paulo

    2009-11-12

    Multiconfiguration second-order perturbation theory, with the inclusion of relativistic effects and spin-orbit coupling, was employed to investigate the nature of the ground and low-lying Lambda-S and Omega states of the TcN molecule. Spectroscopic constants, effective bond order, and potential energy curves for 13 low-lying Lambda-S states and 5 Omega states are given. The computed ground state of TcN is of Omega = 3 symmetry (R(e) = 1.605 A and omega(e) = 1085 cm(-1)), originating mainly from the (3)Delta Lambda-S ground state. This result is contrasted with the nature of the ground state for other VIIB transtion-metal mononitrides, including X(3)Sigma(-) symmetry for MnN and Omega = 0(+) symmetry for ReN, derived also from a X(3)Sigma(-) state.

  14. Florida Court: Vouchers Unconstitutional--Ruling Will End Opportunity Scholarships Program for Students in State's Lowest-Rated Schools

    ERIC Educational Resources Information Center

    Richard, Alan

    2006-01-01

    Florida's voucher program for students in the lowest-rated public schools is unconstitutional, the state supreme court ruled early January 2006 in a 5-2 decision that friends and foes of private school choice are scrutinizing for its potential impact on voucher debates nationwide. Chief Justice Barbara J. Pariente of the Florida Supreme Court…

  15. Isomeric Character of the Lowest Observed 4+ State in 44S

    NASA Astrophysics Data System (ADS)

    Parker, J. J.; Wiedenhöver, I.; Cottle, P. D.; Baker, J.; McPherson, D.; Riley, M. A.; Santiago-Gonzalez, D.; Volya, A.; Bader, V. M.; Baugher, T.; Bazin, D.; Gade, A.; Ginter, T.; Iwasaki, H.; Loelius, C.; Morse, C.; Recchia, F.; Smalley, D.; Stroberg, S. R.; Whitmore, K.; Weisshaar, D.; Lemasson, A.; Crawford, H. L.; Macchiavelli, A. O.; Wimmer, K.

    2017-02-01

    Previous experiments observed a 4+ state in the N =28 nucleus 44S and suggested that this state may exhibit a hindered E 2 -decay rate, inconsistent with being a member of the collective ground state band. We populate this state via two-proton knockout from a beam of exotic 46Ar projectiles and measure its lifetime using the recoil distance method with the GRETINA γ -ray spectrometer. The result, 76 (14 )stat(20 )syst ps , implies a hindered transition of B (E 2 ;4+→21+)=0.61 (19 ) single-particle or Weisskopf units strength and supports the interpretation of the 4+ state as a K =4 isomer, the first example of a high-K isomer in a nucleus of such low mass.

  16. Isomeric Character of the Lowest Observed 4^{+} State in ^{44}S.

    PubMed

    Parker, J J; Wiedenhöver, I; Cottle, P D; Baker, J; McPherson, D; Riley, M A; Santiago-Gonzalez, D; Volya, A; Bader, V M; Baugher, T; Bazin, D; Gade, A; Ginter, T; Iwasaki, H; Loelius, C; Morse, C; Recchia, F; Smalley, D; Stroberg, S R; Whitmore, K; Weisshaar, D; Lemasson, A; Crawford, H L; Macchiavelli, A O; Wimmer, K

    2017-02-03

    Previous experiments observed a 4^{+} state in the N=28 nucleus ^{44}S and suggested that this state may exhibit a hindered E2-decay rate, inconsistent with being a member of the collective ground state band. We populate this state via two-proton knockout from a beam of exotic ^{46}Ar projectiles and measure its lifetime using the recoil distance method with the GRETINA γ-ray spectrometer. The result, 76(14)_{stat}(20)_{syst}  ps, implies a hindered transition of B(E2;4^{+}→2_{1}^{+})=0.61(19) single-particle or Weisskopf units strength and supports the interpretation of the 4^{+} state as a K=4 isomer, the first example of a high-K isomer in a nucleus of such low mass.

  17. Isotope effects and proton hyperfine interactions in the lowest 3n pi * state of substituted benzaldehydes

    NASA Astrophysics Data System (ADS)

    Neugebauer-Crawford, S. M.; Tinti, D. S.

    1995-12-01

    The zero-field splittings, principal spin axes, kinetic parameters, and nuclear hyperfine interactions of the 3nπ* state of p-chloro- and p-methylbenzaldehyde and several of their deuterated derivatives are investigated by zero- and low-field optically detected magnetic resonance (ODMR) at 1.4 K in a p-dimethoxybenzene host. The zero-field splittings show large isotope effects. These are interpreted in terms of spin-orbit interaction with the nearby but higher lying 3ππ* state, yielding the energy gap between the two states in both benzaldehyde derivatives. The locations of the spin axes are approximately along the local symmetry axes of the carbonyl group and are insensitive to isotope. But, the spin axis most nearly normal to the plane of a host molecule deviates from the normal by an angle of 7°-13°. The kinetic parameters of the 3nπ* state also are relatively insensitive to isotope. The dominant hyperfine interactions are associated with the aldehyde hydrogen and indicate that the 3nπ* state is largely localized on the aldehyde moiety. Various properties of the 3nπ* and 3ππ* states are compared.

  18. Experimental and theoretical dipole moments of purines in their ground and lowest excited singlet states

    NASA Astrophysics Data System (ADS)

    Aaron, Jean-Jacques; Diabou Gaye, Mame; Párkányi, Cyril; Cho, Nam Sook; Von Szentpály, László

    1987-01-01

    The ground-state dipole moments of seven biologically important purines (purine, 6-chloropurine, 6-mercaptopurine, hypoxanthine, theobromine, theophylline and caffeine) were determined at 25°C in acetic acid (all the above compounds with the exception of purine) and in ethyl acetate (purine, theophylline and caffeine). Because of its low solubility, it was not possible to measure the dipole moment of uric acid. The first excited singlet-state dipole moments were obtained on the basis of the Bakhshiev and Chamma—Viallet equations using the variation of the Stokes shift with the solvent dielectric constant-refractive index term. The theoretical dipole moments for all the purines listed above and including uric acid were calculated by combining the use of the PPP (π-LCI-SCF-MO) method for the π-contribution to the overall dipole moment with the σ-contribution obtained as a vector sum of the σbond moments and group moments. The experimental and theoretical values were compared with the data available in the literature for some of the purines under study. For several purines, the calculations were carried out for different tautomeric forms. Excited singlet-state dipole moments are smaller than the ground-state values by 0.8 to 2.2 Debye units for all purines under study with the exception of 6-chloropurine. The effects of the structure upon the ground- and excited-state dipole moments of the purines are discussed.

  19. Nonadiabatic effects in the lowest 0+(3P) ion-pair states of CIF

    NASA Astrophysics Data System (ADS)

    Kokh, Daria B.; Li, Yan; Buenker, Robert J.; Alekseyev, Aleksey B.; Liebermann, Heinz-Peter; Alekseev, Vadim A.

    2001-02-01

    Nonadiabatic calculations of vibrational energies and wave functions are carried out for the E(0+, 3P2) and f(0+, 3P0) ion-pair states of the ClF molecule. It is shown that strong radial coupling between these 0+ states is caused by a significant variation of their 3Σ- and 3Π Λ-S contributions with internuclear distance and results in vibrational energy shifts as well as changes in the corresponding adiabatic vibrational wave functions. Both resonance and nonresonance interactions between vibronic levels of these two adiabatic states are found to be important, but significant mixing of the adiabatic wave functions can occur only for the nearly resonant levels located around f,v=3; E,v=7 and f,v=8; E,v=13. Nonadiabatic interactions are found to be responsible for the appearance of long-wavelength maxima in the f,v=3,4 emission spectra that was the subject of the discrepancy between theoretical and experimental data discussed in the previous paper [A. B. Alekseyev, H.-P. Liebermann, R. J. Buenker, and D. B. Kokh, J. Chem. Phys. 112, 2274 (2000)]. Inclusion of nonadiabatic effects leads to notably better agreement between the calculated and measured bound-free emission spectra.

  20. Excitation of the lowest CO2 vibrational states by electrons in hypersonic boundary layers

    NASA Astrophysics Data System (ADS)

    Armenise, I.

    2017-07-01

    The state-to-state vibrational kinetics of a CO2/O2/CO/C/O/e- mixture in a hypersonic boundary layer under conditions compatible with the Mars re-entry is studied. The model adopted treats three CO2 modes (the two degenerated bending modes are approximated as a unique one) as not independent ones. Vibrational-translational transitions in the bending mode, inter-mode exchanges within CO2 molecule and between molecules of different chemical species as well as dissociation-recombination reactions are considered. Attention is paid to the electron-CO2 collisions that cause transitions from the ground vibrational state, CO2(0,0,0), to the first excited ones, CO2(1,0,0), CO2(0,1,0) and CO2(0,0,1). The corresponding processes rate coefficients are obtained starting from the electron energy distribution function, calculated either as an equilibrium Boltzmann distribution at the local temperature or by solving the Boltzmann equation. Results obtained either neglecting or including in the kinetic scheme the electron-CO2 collisions are compared and explained by analysing the rate coefficients of the electron-CO2 collisions.

  1. Dark state with counter-rotating dissipative channels.

    PubMed

    Zhou, Zheng-Yang; Chen, Mi; Wu, Lian-Ao; Yu, Ting; You, J Q

    2017-07-24

    Dark state as a consequence of interference between different quantum states has great importance in the fields of chip-scale atomic clock and quantum information. For the Λ-type three-level system, this dark state is generally regarded as being dissipation-free because it is a superposition of two lowest states without dipole transition between them. However, previous studies are based on the rotating-wave approximation (RWA) by neglecting the counter-rotating terms in the system-environment interaction. In this work, we study non-Markovian quantum dynamics of the dark state in a Λ-type three-level system coupled to two bosonic baths and reveal the effect of counter-rotating terms on the dark state. In contrast to the dark state within the RWA, leakage of the dark state occurs even at zero temperature, as a result of these counter-rotating terms. Also, we present a method to restore the quantum coherence of the dark state by applying a leakage elimination operator to the system.

  2. Theoretical characterization of the lowest triplet excited states of the tris-(1,4,5,8-tetraazaphenanthrene) ruthenium dication complex.

    PubMed

    Alary, Fabienne; Boggio-Pasqua, Martial; Heully, Jean-Louis; Marsden, Colin J; Vicendo, Patricia

    2008-06-16

    We present a theoretical study of the ground and the lowest triplet excited states of the tris-(1,4,5,8-tetraazaphenanthrene) ruthenium complex [Ru(tap)3]2+. Density functional theory (DFT) was used to obtain the relaxed geometries and emission energies (Delta-SCF), whereas time-dependent DFT (TD-DFT) was used to compute the absorption spectrum. Our calculations have revealed the presence of three low-lying excited-state minima, which may be relevant in the photophysical/photochemical properties of this complex. Two minima with similar energies correspond to the MLCT 3A2 and MLCT 3B metal-to-ligand charge-transfer states, the first one corresponding to a D3 structure, whereas the second is a slightly localized C2 species. The third and lowest one corresponds to the metal-centered MC 3A state and displays a pronounced C2 distortion. We have examined for the first time the localized character of the excitation in the computed MLCT states. In particular, we have evaluated the pseudorotation barrier between the Jahn-Teller C2 MLCT 3B minima in the moat around the D3 conical intersection. We have shown that the complex should be viewed as a delocalized [Ru3+(tap(-1/3))3]2+ complex in the lowest MLCT states, in agreement with subpicosecond interligand electron transfer observed by femtosecond transient absorption anisotropy study. Upper-bound estimates of the MLCT-->MC (3 kcal/mol) and MC-->MLCT (10 kcal/mol) activation energy barriers obtained from potential energy profiles in vacuum corroborate the high photoinstability of the MLCT states of the [Ru(tap)3]2+complex.

  3. Single-Molecule Spectroscopy Unmasks the Lowest Exciton State of the B850 Assembly in LH2 from Rps. acidophila

    PubMed Central

    Kunz, Ralf; Timpmann, Kõu; Southall, June; Cogdell, Richard J.; Freiberg, Arvi; Köhler, Jürgen

    2014-01-01

    We have recorded fluorescence-excitation and emission spectra from single LH2 complexes from Rhodopseudomonas (Rps.) acidophila. Both types of spectra show strong temporal spectral fluctuations that can be visualized as spectral diffusion plots. Comparison of the excitation and emission spectra reveals that for most of the complexes the lowest exciton transition is not observable in the excitation spectra due to the cutoff of the detection filter characteristics. However, from the spectral diffusion plots we have the full spectral and temporal information at hand and can select those complexes for which the excitation spectra are complete. Correlating the red most spectral feature of the excitation spectrum with the blue most spectral feature of the emission spectrum allows an unambiguous assignment of the lowest exciton state. Hence, application of fluorescence-excitation and emission spectroscopy on the same individual LH2 complex allows us to decipher spectral subtleties that are usually hidden in traditional ensemble spectroscopy. PMID:24806933

  4. Dynamics of molecules in extreme rotational states

    PubMed Central

    Yuan, Liwei; Teitelbaum, Samuel W.; Robinson, Allison; Mullin, Amy S.

    2011-01-01

    We have constructed an optical centrifuge with a pulse energy that is more than 2 orders of magnitude larger than previously reported instruments. This high pulse energy enables us to create large enough number densities of molecules in extreme rotational states to perform high-resolution state-resolved transient IR absorption measurements. Here we report the first studies of energy transfer dynamics involving molecules in extreme rotational states. In these studies, the optical centrifuge drives CO2 molecules into states with J ∼ 220 and we use transient IR probing to monitor the subsequent rotational, translational, and vibrational energy flow dynamics. The results reported here provide the first molecular insights into the relaxation of molecules with rotational energy that is comparable to that of a chemical bond.

  5. Nonlinear optical spectra having characteristics of Fano interferences in coherently coupled lowest exciton biexciton states in semiconductor quantum dots

    SciTech Connect

    Gotoh, Hideki Sanada, Haruki; Yamaguchi, Hiroshi; Sogawa, Tetsuomi

    2014-10-15

    Optical nonlinear effects are examined using a two-color micro-photoluminescence (micro-PL) method in a coherently coupled exciton-biexciton system in a single quantum dot (QD). PL and photoluminescence excitation spectroscopy (PLE) are employed to measure the absorption spectra of the exciton and biexciton states. PLE for Stokes and anti-Stokes PL enables us to clarify the nonlinear optical absorption properties in the lowest exciton and biexciton states. The nonlinear absorption spectra for excitons exhibit asymmetric shapes with peak and dip structures, and provide a distinct contrast to the symmetric dip structures of conventional nonlinear spectra. Theoretical analyses with a density matrix method indicate that the nonlinear spectra are caused not by a simple coherent interaction between the exciton and biexciton states but by coupling effects among exciton, biexciton and continuum states. These results indicate that Fano quantum interference effects appear in exciton-biexciton systems at QDs and offer important insights into their physics.

  6. Accurate ab initio potential energy curves and spectroscopic properties of the four lowest singlet states of C2

    SciTech Connect

    Boschen, Jeffery S.; Theis, Daniel; Ruedenberg, Klaus; Windus, Theresa L.

    2013-12-07

    The diatomic carbon molecule has a complex electronic structure with a large number of low-lying electronic excited states. In this work, the potential energy curves (PECs) of the four lowest lying singlet states (X-1 Sigma(+)(g), A(1)Pi(u), B-1 Delta(g), and B'(1)Sigma(+)(g)) were obtained by high-level ab initio calculations. Valence electron correlation was accounted for by the correlation energy extrapolation by intrinsic scaling (CEEIS) method. Additional corrections to the PECs included core-valence correlation and relativistic effects. Spin-orbit corrections were found to be insignificant. The impact of using dynamically weighted reference wave functions in conjunction with CEEIS was examined and found to give indistinguishable results from the even weighted method. The PECs showed multiple curve crossings due to the B-1 Delta(g) state as well as an avoided crossing between the two (1)Sigma(+)(g) states. Vibrational energy levels were computed for each of the four electronic states, as well as rotational constants and spectroscopic parameters. Comparison between the theoretical and experimental results showed excellent agreement overall. Equilibrium bond distances are reproduced to within 0.05 %. The dissociation energies of the states agree with experiment to within similar to 0.5 kcal/mol, achieving "chemical accuracy." Vibrational energy levels show average deviations of similar to 20 cm(-1) or less. The B-1 Delta(g) state shows the best agreement with a mean absolute deviation of 2.41 cm(-1). Calculated rotational constants exhibit very good agreement with experiment, as do the spectroscopic constants.

  7. Effect of the solvent environment on the spectroscopic properties and dynamics of the lowest excited states of carotenoids

    SciTech Connect

    Frank, H.A.; Bautista, J.A.; Josue, J.; Pendon, Z.; Hiller, R.G.; Sharples, F.P.; Gosztola, D.; Wasielewski, M.R.

    2000-05-11

    The spectroscopic properties and dynamics of the lowest excited singlet states of peridinin, fucoxanthin, neoxanthin, uriolide acetate, spheroidene, and spheroidenone in several different solvents have been studied by steady-state absorption and fast-transient optical spectroscopic techniques. Peridinin, fucoxanthin, uriolide acetate, and spheroidenone, which contain carbonyl functional groups in conjugation with the carbon-carbon {pi}-electron system, display broader absorption spectral features and are affected more by the solvent environment than neoxanthin and spheroidene, which do not contain carbonyl functional groups. The possible sources of the spectral broadening are explored by examining the absorption spectra at 77 K in glassy solvents. Also, carotenoids which contain carbonyls have complex transient absorption spectra and show a pronounced dependence of the excited singlet state lifetime on the solvent environment. It is postulated that these effects are related to the presence of an intramolecular charge transfer state strongly coupled to the S{sub 1} (2{sup 1}A{sub g}) excited singlet state. Structural variations in the series of carotenoids studied here make it possible to focus on the general molecular features that control the spectroscopic and dynamic properties of carotenoids.

  8. Study of Topological Effects Concerning the Lowest A″ and the Three A' States for the CO2(+) Ion.

    PubMed

    Dhindhwal, Vikash; Baer, Michael; Sathyamurthy, N

    2016-05-19

    A study of the topological effects, viz., the Jahn-Teller (JT) and Renner-Teller (RT) effects, in CO2(+) has been carried out by calculating nonadiabatic coupling terms (NACTs) at the state-averaged CASSCF level using the cc-pVTZ basis set for the lowest three A' states and one A″ state along a circular contour. Using the NACTs, the privileged adiabatic-to-diabatic transformation (ADT) angles (γ12) for 1A' and 2A' states of CO2(+) have been calculated along various circular contours. Employing one of the oxygen atoms as the test particle exposed two conical intersections (ci) located on each side of the CO diatom. The main purpose of this study is to explore the possibility of forming reliable diabatic potential energy surfaces for this system. Success in achieving this goal is guaranteed by the ability to calculate quantized privileged ADT angles along closed contours covering large regions in configuration space (see, e.g., J. Phys. Chem. A 2014 , 118 , 6361 ). The calculations were carried out for two and three JT states. In most cases very nice quantization has been achieved although the calculations were frequently done, as required, for large regions in configuration space (sometimes ≥18 Å(2)). In one case, for which the quantization was not gratifying, the inclusion of the RT effect modified it considerably.

  9. The four final rotation states of Venus.

    PubMed

    Correia, A C; Laskar, J

    2001-06-14

    Venus rotates very slowly on its axis in a retrograde direction, opposite to that of most other bodies in the Solar System. To explain this peculiar observation, it has been generally believed that in the past its rotational axis was itself rotated to 180 degrees as a result of core-mantle friction inside the planet, together with atmospheric tides. But such a change has to assume a high initial obliquity (the angle between the planet's equator and the plane of the orbital motion). Chaotic evolution, however, allows the spin axis to flip for a large set of initial conditions. Here we show that independent of uncertainties in the models, terrestrial planets with dense atmosphere like Venus can evolve into one of only four possible rotation states. Moreover, we find that most initial conditions will drive the planet towards the configuration at present seen at Venus, albeit through two very different evolutionary paths. The first is the generally accepted view whereby the spin axis flips direction. But we have also found that it is possible for Venus to begin with prograde rotation (the same direction as the other planets) yet then develop retrograde rotation while the obliquity goes towards zero: a rotation of the spin axis is not necessary in this case.

  10. Parafermionic states in rotating Bose-Einstein condensates

    NASA Astrophysics Data System (ADS)

    Regnault, N.; Jolicoeur, Th.

    2007-12-01

    We investigate some properties of the parafermionic states, which may occur in rapidly rotating ultracold bosonic atomic gases at lowest Landau level filling factor ν=k/2 (with k integer ⩾2 ). These states have manifolds of quasihole states, which are expected to display non-Abelian statistics. We use exact diagonalizations in the spherical geometry to investigate the quasihole manifolds for quantum Hall states at ν=1 , 3/2 , 2, and 5/2 . We show that there is a perfect agreement between numerical findings and the prediction of conformal field theory concerning the number of orbital angular momentum multiplets as a function of added vorticity. The overlap between quasihole candidate wave functions and the corresponding states for realistic delta function interactions between bosons is computed. This allows us to discuss the possible relevance of non-Abelian degeneracy in the physical situation of ultracold atoms.

  11. Effect of hydration on the lowest singlet PiPi* excited-state geometry of guanine: a theoretical study.

    PubMed

    Shukla, M K; Leszczynski, Jerzy

    2005-09-15

    An ab-initio computational study was performed to investigate the effect of explicit hydration on the ground and lowest singlet PiPi* excited-state geometry and on the selected stretching vibrational frequencies corresponding to the different NH sites of the guanine acting as hydrogen-bond donors. The studied systems consisted of guanine interacting with one, three, five, six, and seven water molecules. Ground-state geometries were optimized at the HF level, while excited-state geometries were optimized at the CIS level. The 6-311G(d,p) basis set was used in all calculations. The nature of potential energy surfaces was ascertained via the harmonic vibrational frequency analysis; all structures were found minima at the respective potential energy surfaces. The changes in the geometry and the stretching vibrational frequencies of hydrogen-bond-donating sites of the guanine in the ground and excited state consequent to the hydration are discussed. It was found that the first solvation shell of the guanine can accommodate up to six water molecules. The addition of the another water molecule distorts the hydrogen-bonding network by displacing other neighboring water molecules away from the guanine plane.

  12. Deactivation processes of the lowest excited state of [UO2(H2O)5]2+ in aqueous solution.

    PubMed

    Formosinho, Sebastião J; Burrows, Hugh D; da Graça Miguel, Maria; Azenha, M Emília D G; Saraiva, Isabel M; Ribeiro, A Catarina D N; Khudyakov, Igor V; Gasanov, Rashid G; Bolte, Michèle; Sarakha, Mohamed

    2003-05-01

    A detailed analysis of the photophysical behaviour of uranyl ion in aqueous solutions at room temperature is given using literature data, together with results of new experimental and theoretical studies to see whether the decay mechanism of the lowest excited state involves physical deactivation by energy transfer or a chemical process through hydrogen atom abstraction. Comparison of the radiative lifetimes determined from quantum yield and lifetime data with that obtained from the Einstein relationship strongly suggests that the emitting state is identical to that observed in the lowest energy absorption band. From study of the experimental rate and that calculated theoretically, from deuterium isotope effects and the activation energy for decay support is given to a deactivation mechanism of hydrogen abstraction involving water clusters to give uranium(v) and hydroxyl radicals. Support for hydroxyl radical formation comes from electron spin resonance spectra observed in the presence of the spin traps 5,5-dimethyl-1-pyrroline N-oxide and tert-butyl-N-phenylnitrone and from literature results on photoinduced uranyl oxygen exchange and photoconductivity. It has previously been suggested that the uranyl emission above pH 1.5 may involve an exciplex between excited uranyl ion and uranium(v). Evidence against this mechanism is given on the basis of quenching of uranyl luminescence by uranium(v), together with other kinetic reasoning. No overall photochemical reaction is observed on excitation of aqueous uranyl solutions, and it is suggested that this is mainly due to reoxidation of UO2+ by hydroxyl radicals in a radical pair. An alternative process involving oxidation by molecular oxygen is analysed experimentally and theoretically, and is suggested to be too slow to be a major reoxidation pathway.

  13. The g factor of the lowest 7+ state in100Rh and 6- state in104Rh

    NASA Astrophysics Data System (ADS)

    Bizzeti-Sona, A. M.; Blasi, P.; Donvito, M.; Stefanini, A. A.; Bazzacco, D.; Brandolini, F.; Löwenich, K.; Pavan, P.; Rossi-Alvarez, C.; de Poli, M.; Haque, A. M. I.

    1990-12-01

    The g-factor of the 7+ state in100Rh with T 1/2=140(5) ns and of the 6- state in104Rh with T 1/2=47(3)ns has been measured by the time-differential perturbed γ-ray angular distribution method (TDPAD). The obtained values are +0.67(2) and +0.33(1) respectively. The two nuclei were populated with reactions induced by7Li on96,100Mo at a bombarding energy of 30 MeV. Shell model calculations using effective single particle moments show that the 7+ state in100Rh has mostly a π g 9/2 ⊗ v d 5/2 configuration, while the main component of the 6- state in104Rh is the π g 9/2 ⊗ v h 11/2.

  14. Mutual Co-Assignment of the Calculated Vibrational Frequencies in the Ground and Lowest Excited Electronic States

    NASA Astrophysics Data System (ADS)

    Panchenko, Yurii N.

    2013-06-01

    The shifts of the molecular vibrational frequencies when going from the ground electronic state to the lowest excited electronic states pose some problems for the mutual co-assignment of the calculated vibrational frequencies in the different excited states. The trans-{C_2 O_2 F_2} shift of the frequency of the symmetrical ν(C=O) stretching vibration between the S_0 and T_1 is 373 wn. The feasibility of mutual co-assignments of the vibrational frequencies in these electronic states has been demonstrated for trans-{C_2 O_2 F_2}. Matrices analogous to the Duschinsky matrix were used to juxtapose the a_g vibrational frequencies of this molecule calculated at the CASPT2/cc-pVTZ level in the ground S_0 and excited triplet T_1 and singlet S_1 electronic states. The analog of the Duschinsky matrix D was obtained for this molecule using the equation D = (L_{I})^{-1} L_{II} where L_{I} and L_{II} are the matrices of the vibrational modes (normalized atomic displacements) obtained by solving the vibrational problems for the S_0 and T_1 electronic states, respectively. Choosing the dominant elements in columns of the D matrix and permuting these columns to arrange these elements along the diagonal of the transformed matrix D^* makes it possible to establish the correct mutual co-assignments of the calculated a_g vibrational frequencies of the trans-{C_2 O_2 F_2} molecule in the S_0 and T_1 electronic states. The analogous procedure was performed for the trans-{C_2 O_2 F_2} molecule in the T_1 and S_1 excited electronic states. The recent reassignments of the νb{2} and νb{3} calculated vibrational frequencies in the trans-{C_2 O_2 F_2} molecule in the ground state were also obtained for the triplet T_1 and singlet S_1 excited electronic states. The approach set forth in this text makes it possible to juxtapose the calculated vibrational frequencies of the same molecule in the different electronic states and to refine the assignments of these frequencies. This is essential

  15. Excited state properties of peridinin: Observation of a solvent dependence of the lowest excited singlet state lifetime and spectral behavior unique among carotenoids

    SciTech Connect

    Bautista, J.A.; Connors, R.E.; Raju, B.B.; Hiller, R.G.; Sharples, F.P.; Gosztola, D.; Wasielewski, M.R.; Frank, H.A.

    1999-10-14

    The spectroscopic properties and dynamic behavior of peridinin in several different solvents were studied by steady-state absorption, fluorescence, and transient optical spectroscopy. The lifetime of the lowest excited singlet state of peridinin is found to be strongly dependent on solvent polarity and ranges from 7 ps in the strongly polar solvent trifluoroethanol to 172 ps in the nonpolar solvents cyclohexane and benzene. The lifetimes show no obvious correlation with solvent polarizability, and hydrogen bonding of the solvent molecules to peridinin is not an important factor in determining the dynamic behavior of the lowest excited singlet state. The wavelengths of emission maxima, the quantum yields of fluorescence, and the transient absorption spectra are also affected by the solvent environment. A model consistent with the data and supported by preliminary semiempirical calculations invokes the presence of a charge transfer state in the excited state manifold of peridinin to account for the observations. The charge transfer state most probably results from the presence of the lactone ring in the {pi}-electron conjugation of peridinin analogous to previous findings on aminocoumarins and related compounds. The behavior of peridinin reported here is highly unusual for carotenoids, which generally show little dependence of the spectral properties and lifetimes of the lowest excited singlet state on the solvent environment.

  16. Conical intersections and diabatic potential energy surfaces for the three lowest electronic singlet states of H3 (+).

    PubMed

    Mukherjee, Saikat; Mukhopadhyay, Debasis; Adhikari, Satrajit

    2014-11-28

    We calculate the adiabatic Potential Energy Surfaces (PESs) and the Non-Adiabatic Coupling Terms (NACTs) for the three lowest singlet states of H3 (+) in hyperspherical coordinates as functions of hyperangles (θ and ϕ) for a grid of fixed values of hyperradius (1.5 ⩽ ρ ⩽ 20 bohrs) using the MRCI level of methodology employing ab initio quantum chemistry package (MOLPRO). The NACT between the ground and the first excited state translates along the seams on the θ - ϕ space, i.e., there are six Conical Intersections (CIs) at each θ (60° ⩽ θ ⩽ 90°) within the domain, 0 ⩽ ϕ ⩽ 2π. While transforming the adiabatic PESs to the diabatic ones, such surfaces show up six crossings along those seams. Our beyond Born-Oppenheimer approach could incorporate the effect of NACTs accurately and construct single-valued, continuous, smooth, and symmetric diabatic PESs. Since the location of CIs and the spatial amplitudes of NACTs are most prominent around ρ = 10 bohrs, generally only those results are depicted.

  17. Topological origin and not purely antisymmetric wave functions of many-body states in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Łydżba, P.; Jacak, J.

    2017-01-01

    In this paper, we recall the topological approach to quantum Hall effects. We note that, in the presence of a magnetic field, trajectories representing elements of the system's braid group are of cyclotron orbit type. In two-dimensional spaces, this leads to the restriction of the full braid group, π1(Ω)-loopless generators (exchanges of MN coordinates or classical particles) are unenforceable. As a result, the identification of a possible Hall-like state comes down to the identification of a possible subgroup of π1(Ω). The latter follows from the connection between the one-dimensional unitary representation of the system's braid group and particle statistics (unavoidable for any correlated state). In this work, we implement the topological approach to derive the lowest Landau-level pyramid of fillings. We point out that it contains all mysterious odd-denominator filling factors-like 4/11 , 4/13 or 6/17 -not trivial to explain within the standard picture. We also introduce, explicitly, cyclotron subgroup generators for all derived fractions. Preliminary results on wave functions, supported by several Monte Carlo calculations, are presented. It is worth emphasizing that not all proposed many-body functions are purely antisymmetric-they, however, transform in agreement with the scalar representations of the system's braid group. The latter is enforced by standard quantization methods.

  18. Topological origin and not purely antisymmetric wave functions of many-body states in the lowest Landau level.

    PubMed

    Łydżba, P; Jacak, J

    2017-01-01

    In this paper, we recall the topological approach to quantum Hall effects. We note that, in the presence of a magnetic field, trajectories representing elements of the system's braid group are of cyclotron orbit type. In two-dimensional spaces, this leads to the restriction of the full braid group, π1(Ω)-loopless generators (exchanges of M(N) coordinates or classical particles) are unenforceable. As a result, the identification of a possible Hall-like state comes down to the identification of a possible subgroup of π1(Ω). The latter follows from the connection between the one-dimensional unitary representation of the system's braid group and particle statistics (unavoidable for any correlated state). In this work, we implement the topological approach to derive the lowest Landau-level pyramid of fillings. We point out that it contains all mysterious odd-denominator filling factors-like [Formula: see text], [Formula: see text] or [Formula: see text]-not trivial to explain within the standard picture. We also introduce, explicitly, cyclotron subgroup generators for all derived fractions. Preliminary results on wave functions, supported by several Monte Carlo calculations, are presented. It is worth emphasizing that not all proposed many-body functions are purely antisymmetric-they, however, transform in agreement with the scalar representations of the system's braid group. The latter is enforced by standard quantization methods.

  19. S1←S0 vibronic spectra and structure of cyclopropanecarboxaldehyde molecule in the S1 lowest excited singlet electronic state

    NASA Astrophysics Data System (ADS)

    Godunov, I. A.; Yakovlev, N. N.; Terentiev, R. V.; Maslov, D. V.; Bataev, V. A.; Abramenkov, A. V.

    2016-11-01

    The S1←S0 vibronic spectra of gas-phase absorption at room temperature and fluorescence excitation of jet-cooled cyclopropanecarboxaldehyde (CPCA, c-C3H5CHO)were obtained and analyzed. In addition, the quantum chemical calculation (CASPT2/cc-pVTZ)was carried out for CPCA in the ground (S0) and lowest excited singlet (S1) electronic states. As a result, it was proved that the S1←S0 electronic excitation of the CPCA conformers (syn and anti) causes (after geometrical relaxation) significant structural changes, namely, the carbonyl fragments become non-planar and the cyclopropyl groups rotate around the central C-C bond. As a consequence, the potential energy surface of CPCA in the S1 state has six minima, 1ab, 2ab, and 3ab, corresponding to three pairs of mirror symmetry conformers: a and b. It was shown that vibronic bands of experimental spectra can be assigned to the 2(S1)←syn(S0) electronic transition with the origin at 30,481 cm-1. A number of fundamental vibrational frequencies for the 2 conformer of CPCA were assigned. In addition, several inversional energy levels for the 2 conformer were found and the 2a↔2b potential function of inversion was determined. The experimental barrier to inversion and the equilibrium angle between the CH bond and the CCO plane were calculated as 570 cm-1 and 28°, respectively.

  20. Zero-field-splitting and π-electron spin densities in the lowest excited triplet state of oligothiophenes

    NASA Astrophysics Data System (ADS)

    Bennati, M.; Németh, K.; Surján, P. R.; Mehring, M.

    1996-09-01

    The electronic properties of thiophene oligomers (nT, n=2-8) have been investigated in the lowest excited triplet state. Theoretical calculations of the zero field splitting parameters and of the π-electron spin density have been performed and compared with previous experimental EPR results. The calculations are based on a simple π-electron (one-electron-per-site) model including electron-electron interaction at the extended Hubbard level. Optimized bond lengths result from making them self-consistent to the corresponding bond orders via Coulson's relationship. The calculated D values decrease from D=0.0959 cm-1 for n=2 to D=0.0597 cm-1 for n=8, in agreement with EPR data. The measured as well as the calculated E values are rather small. Furthermore, we found that ZFS parameters are affected by the torsion angles between the thiophene rings. The chain length dependence of D can be rationalized comparing π-electron spin density calculations and computed bond length distortions. These clearly indicate that the triplet excitation reaches a finite extension over about four thiophene rings.

  1. Hyper Open-Shell States: The Lowest Excited Spin States of O Atom, Fe(2+) Ion, and FeF2.

    PubMed

    Varga, Zoltan; Verma, Pragya; Truhlar, Donald G

    2017-09-13

    Excited spin states are important for reactivity, catalysis, and magnetic applications. This work examines the relative energies of the spin states of O atom, Fe(2+) ion, and FeF2 and characterizes their excited spin states. Both single-configuration and multireference methods are used to establish the character of the lowest singlet excited state of all three systems and the lowest triplet excited state of Fe(2+) and FeF2. We find that the conventional representation of the orbital occupancies is incorrect in that the states have more unpaired electrons than the minimum number required by their total electron spin quantum number. In particular, we find that, for a given spin state, an electronic configuration with more than 2S unpaired electrons is more stable than the configuration with 2S unpaired electrons (where S is the spin of the system). For instance, triplet FeF2 with four unpaired electrons is lower in energy than triplet FeF2 with two unpaired electrons. Such highly open-shell configurations are labeled as hyper open-shell electronic configurations in this work and are compared to ordinary open-shell or closed-shell electronic configurations. The hyper open-shell states considered in this work are especially interesting because, unlike typical biradicals and polyradicals, the unpaired electrons are all on the same center. This work shows that the conventional perspective on spin-state energetics that usually assumes ordinary open shells for single-centered radicals needs modification to take into account, whenever possible, hyper open-shell configurations as well.

  2. Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations.

    PubMed

    Śmiałek, M A; Łabuda, M; Guthmuller, J; Hubin-Franskin, M-J; Delwiche, J; Duflot, D; Mason, N J; Hoffmann, S V; Jones, N C; Limão-Vieira, P

    2014-09-14

    The highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C2H5OCHO, yet reported is presented over the wavelength range 115.0-275.5 nm (10.75-4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of ethyl formate and are compared with a newly recorded He(I) photoelectron spectrum (from 10.1 to 16.1 eV). New vibrational structure is observed in the first photoelectron band. The photoabsorption cross sections have been used to calculate the photolysis lifetime of ethyl formate in the upper stratosphere (20-50 km).

  3. Valence and ionic lowest-lying electronic states of ethyl formate as studied by high-resolution vacuum ultraviolet photoabsorption, He(I) photoelectron spectroscopy, and ab initio calculations

    SciTech Connect

    Śmiałek, M. A.; Duflot, D.; Mason, N. J.; Hoffmann, S. V.; Jones, N. C.; Limão-Vieira, P.

    2014-09-14

    The highest resolution vacuum ultraviolet photoabsorption spectrum of ethyl formate, C{sub 2}H{sub 5}OCHO, yet reported is presented over the wavelength range 115.0–275.5 nm (10.75–4.5 eV) revealing several new spectral features. Valence and Rydberg transitions and their associated vibronic series, observed in the photoabsorption spectrum, have been assigned in accordance with new ab initio calculations of the vertical excitation energies and oscillator strengths. Calculations have also been carried out to determine the ionization energies and fine structure of the lowest ionic state of ethyl formate and are compared with a newly recorded He(I) photoelectron spectrum (from 10.1 to 16.1 eV). New vibrational structure is observed in the first photoelectron band. The photoabsorption cross sections have been used to calculate the photolysis lifetime of ethyl formate in the upper stratosphere (20–50 km)

  4. State Funds for Higher Education Total $34-Billion; 11-Pct. Biennial Rise Equals Lowest in 29 Years.

    ERIC Educational Resources Information Center

    Jaschik, Scott

    1987-01-01

    Tight state budgets and regional economic difficulties have prompted a sharp drop in the rate that state appropriations for higher education have increased over the past two years. New England fares well while farm and oil states suffer. (MLW)

  5. State Funds for Higher Education Total $34-Billion; 11-Pct. Biennial Rise Equals Lowest in 29 Years.

    ERIC Educational Resources Information Center

    Jaschik, Scott

    1987-01-01

    Tight state budgets and regional economic difficulties have prompted a sharp drop in the rate that state appropriations for higher education have increased over the past two years. New England fares well while farm and oil states suffer. (MLW)

  6. Lowest electronic states of the CP47 antenna protein complex of photosystem II: simulation of optical spectra and revised structural assignments.

    PubMed

    Reppert, Mike; Acharya, Khem; Neupane, Bhanu; Jankowiak, Ryszard

    2010-09-16

    In this work, we present simulated steady-state absorption, emission, and nonresonant hole burning (HB) spectra for the CP47 antenna complex of photosystem II (PS II) based on fits to recently refined experimental data (Neupane et al. J. Am. Chem. Soc. 2010, 132, 4214). Excitonic simulations are based on the 2.9 Å resolution structure of the PS II core from cyanobacteria (Guskov et al. Nat. Struct. Mol. Biol. 2009, 16, 334), and allow for preliminary assignment of the chlorophylls (Chls) contributing to the lowest excitonic states. The search for realistic site energies was guided by experimental constraints and aided by simple fitting algorithms. The following experimental constraints were used: (i) the oscillator strength of the lowest-energy state should be approximately ≤0.5 Chl equivalents; (ii) the excitonic structure must explain the experimentally observed red-shifted (∼695 nm) emission maximum; and (iii) the excitonic interactions of all states must properly describe the broad (non-line-narrowed, NLN) HB spectrum (including its antihole) whose shape is extremely sensitive to the excitonic structure of the complex, especially the lowest excitonic states. Importantly, our assignments differ significantly from those previously reported by Raszewski and Renger (J. Am. Chem. Soc. 2008, 130, 4431), due primarily to differences in the experimental data simulated. In particular, we find that the lowest state localized on Chl 526 possesses too high of an oscillator strength to fit low-temperature experimental data. Instead, we suggest that Chl 523 most strongly contributes to the lowest excitonic state, with Chl 526 contributing to the second excitonic state. Since the fits of nonresonant holes are more restrictive (in terms of possible site energies) than those of absorption and emission spectra, we suggest that fits of linear optical spectra along with HB spectra provide more realistic site energies.

  7. Density functional theory calculations on rhodamine B and pinacyanol chloride. Optimized ground state, dipole moment, vertical ionization potential, adiabatic electron affinity and lowest excited triplet state.

    PubMed

    Delgado, Juan C; Selsby, Ronald G

    2013-01-01

    The ground state configuration of the gas phase cationic dyes pinacyanol chloride and rhodamine B are optimized with HF/6-311 + G(2d,2p) method and basis set. B3PW91/6-311 + G(2df,2p) functional and basis set is used to calculate the Mulliken atom charge distribution, total molecular energy, the dipole moment, the vertical ionization potential, the adiabatic electron affinity and the lowest excited triplet state, the last three as an energy difference between separately calculated open shell and ground states. The triplet and extra electron states are optimized to find the relaxation energy. In the ground state optimization of both dyes the chloride anion migrates to a position near the center of the chromophore. For rhodamine B the benzoidal group turns perpendicular to the chromophore plane. For both dyes, the LUMO is mostly of π character associated with the aromatic part of the molecule containing the chromophore. The highest occupied MOs consist of three almost degenerate eigenvectors involving the chloride anion coordinated with σ electrons in the molecular framework. The fourth highest MO is of π character. For both molecules in the gas phase ionization process the chloride anion loses the significant fraction of electric charge. In electron capture, the excess charge goes mainly on the dye cation.

  8. High-K multi-quasiparticle states and rotational bands in {sub 103}{sup 255}Lr

    SciTech Connect

    Jeppesen, H. B.; Clark, R. M.; Gregorich, K. E.; Cromaz, M.; Deleplanque, M. A.; Dvorak, J.; Fallon, P.; Gros, S.; Lee, I. Y.; Macchiavelli, A. O.; Stavsetra, L.; Stephens, F. S.; Wiedeking, M.; Afanasjev, A. V.; Ali, M. N.; Dragojevic, I.; Ellison, P. A.; Garcia, M. A.; Gates, J. M.; Nelson, S. L.

    2009-09-15

    Two isomeric states have been identified in {sup 255}Lr. The decay of the isomers populates rotational structures. Comparison with macroscopic-microscopic calculations suggests that the lowest observed sequence is built upon the [624]9/2{sup +} Nilsson state. However, microscopic cranked relativistic Hartree-Bogoliubov (CRHB) calculations do not reproduce the moment of inertia within typical accuracy. This is a clear challenge to theories describing the heaviest elements.

  9. Relativistic four-component potential energy curves for the lowest 23 covalent states of molecular bromine (Br2).

    PubMed

    Gomes, José da Silva; Gargano, Ricardo; Martins, João B L; M de Macedo, Luiz Guilherme

    2014-08-07

    The covalent excited states and ground state of the Br2 molecule has been investigated by using four-component relativistic COSCI and MRCISD methods. These methods were performed for all covalent states in the representation Ω((±)). Calculated potential energy curves (PECs) were obtained at the four-component COSCI level, and spectroscopic constants (R(e), D(e), D0, ω(e), ω(e)x(e), ω(e)y(e), B(e), α(e), γ(e), Te, Dv) for bounded states are reported. The vertical excitations for all covalent states are reported at COSCI, MRCISD, and MRCISD+Q levels. We also present spectroscopic constants for two weakly bounded states (A':(1)2u and B':(1)0(-)u) not yet reported in the literature, as well as accurate analytical curves for all five relativistic molecular bounded sates [the ground state X:0 g(+) and the excited states A:(1)1(u), B:(1)0(u)(+), C:(2)1(u), and B':(1)0(u)(-)] found in this work.

  10. Steady States of the Parametric Rotator and Pendulum

    ERIC Educational Resources Information Center

    Bouzas, Antonio O.

    2010-01-01

    We discuss several steady-state rotation and oscillation modes of the planar parametric rotator and pendulum with damping. We consider a general elliptic trajectory of the suspension point for both rotator and pendulum, for the latter at an arbitrary angle with gravity, with linear and circular trajectories as particular cases. We treat the…

  11. Steady States of the Parametric Rotator and Pendulum

    ERIC Educational Resources Information Center

    Bouzas, Antonio O.

    2010-01-01

    We discuss several steady-state rotation and oscillation modes of the planar parametric rotator and pendulum with damping. We consider a general elliptic trajectory of the suspension point for both rotator and pendulum, for the latter at an arbitrary angle with gravity, with linear and circular trajectories as particular cases. We treat the…

  12. Identifying the lowest electronic states of the chlorophylls in the CP47 core antenna protein of photosystem II.

    PubMed

    De Weerd, Frank L; Palacios, Miguel A; Andrizhiyevskaya, Elena G; Dekker, Jan P; Van Grondelle, Rienk

    2002-12-24

    CP47 is a pigment-protein complex in the core of photosystem II that tranfers excitation energy to the reaction center. Here we report on a spectroscopic investigation of the isolated CP47 complex. By deconvoluting the 77 K absorption and linear dichroism, red-most states at 683 and 690 nm have been identified with oscillator strengths corresponding to approximately 3 and approximately 1 chlorophyll, respectively. Both states contribute to the 4 K emission, and the Stark spectrum shows that they have a large value for the difference polarizability between their ground and excited states. From site-selective polarized triplet-minus-singlet spectra, an excitonic origin for the 683 nm state was found. The red shift of the 690 nm state is most probably due to strong hydrogen bonding to a protein ligand, as follows from the position of the stretch frequency of the chlorophyll 13(1) keto group (1633 cm(-)(1)) in the fluorescence line narrowing spectrum at 4 K upon red-most excitation. We discuss how the 683 and 690 nm states may be linked to specific chlorophylls in the crystal structure [Zouni, A., Witt, H.-T., Kern, J., Fromme, P., Krauss, N., Saenger, W., and Orth, P. (2001) Nature 409, 739-743].

  13. Benchmark calculations on the lowest-energy singlet, triplet, and quintet states of the four-electron harmonium atom

    SciTech Connect

    Cioslowski, Jerzy; Strasburger, Krzysztof; Matito, Eduard

    2014-07-28

    For a wide range of confinement strengths ω, explicitly-correlated calculations afford approximate energies E(ω) of the ground and low-lying excited states of the four-electron harmonium atom that are within few μhartree of the exact values, the errors in the respective energy components being only slightly higher. This level of accuracy constitutes an improvement of several orders of magnitude over the previously published data, establishing a set of benchmarks for stringent calibration and testing of approximate electronic structure methods. Its usefulness is further enhanced by the construction of differentiable approximants that allow for accurate computation of E(ω) and its components for arbitrary values of ω. The diversity of the electronic states in question, which involve both single- and multideterminantal first-order wavefunctions, and the availability of the relevant natural spinorbitals and their occupation numbers make the present results particularly useful in research on approximate density-matrix functionals. The four-electron harmonium atom is found to possess the {sup 3}P{sub +} triplet ground state at strong confinements and the {sup 5}S{sub −} quintet ground state at the weak ones, the energy crossing occurring at ω ≈ 0.0240919.

  14. The order of three lowest-energy states of the six-electron harmonium at small force constant

    NASA Astrophysics Data System (ADS)

    Strasburger, Krzysztof

    2016-06-01

    The order of low-energy states of six-electron harmonium is uncertain in the case of strong correlation, which is not a desired situation for the model system being considered for future testing of approximate methods of quantum chemistry. The computational study of these states has been carried out at the frequency parameter ω = 0.01, using the variational method with the basis of symmetry-projected, explicitly correlated Gaussian (ECG) lobe functions. It has revealed that the six-electron harmonium at this confinement strength is an octahedral Wigner molecule, whose order of states is different than in the strong confinement regime and does not agree with the earlier predictions. The results obtained for ω = 0.5 and 10 are consistent with the findings based on the Hund's rules for the s2p4 electron configuration. Substantial part of the computations has been carried out on the graphical processing units and the efficiency of these devices in calculation of the integrals over ECG functions has been compared with traditional processors.

  15. Solid state replacement of rotating mirror cameras

    NASA Astrophysics Data System (ADS)

    Frank, Alan M.; Bartolick, Joseph M.

    2007-01-01

    Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed 'In-situ Storage Image Sensor' or 'ISIS', by Prof. Goji Etoh has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.

  16. Solid State Replacement of Rotating Mirror Cameras

    SciTech Connect

    Frank, A M; Bartolick, J M

    2006-08-25

    Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed ''In-situ Storage Image Sensor'' or ''ISIS'', by Prof. Goji Etoh, has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.

  17. Short Rotation Crops in the United States

    SciTech Connect

    Wright, L L

    1998-06-04

    The report is based primarily on the results of survey questions sent to approximately 60 woody and 20 herbaceous crop researchers in the United States and on information from the U.S. Department of Energy's Bioenergy Feedstock Development Program. Responses were received from 13 individuals involved in woody crops research or industrial commercialization (with 5 of the responses coming from industry). Responses were received from 11 individuals involved in herbaceous crop research. Opinions on market incentives, technical and non-technical barriers, and highest priority research and development areas are summarized in the text. Details on research activities of the survey responders are provided as appendices to the paper. Woody crops grown as single-stem systems (primarily Populus and Eucalyptus species) are perceived to have strong pulp fiber and oriented strand board markets, and the survey responders anticipated that energy will comprise 25% or less of the utilization of single-stem short-rotation woody crops between now and 2010. The only exception was a response from California where a substantial biomass energy market does currently exist. Willows (Salix species) are only being developed for energy and only in one part of the United States at present. Responses from herbaceous crop researchers suggested frustration that markets (including biomass energy markets) do not currently exist for the crop, and it was the perception of many that federal incentives will be needed to create such markets. In all crops, responses indicate that a wide variety of research and development activities are needed to enhance the yields and profitability of the crops. Ongoing research activities funded by the U.S. Department of Energy's Bioenergy Feedstock Development Program are described in an appendix to the paper.

  18. Transient resonance Raman spectra of benzophenone and its four isotopic analogues in the lowest excited triplet state

    SciTech Connect

    Tahara, T.; Hamaguchi, H.; Tasumi, M.

    1987-11-05

    Transient resonance Raman spectra of T/sub 1/ benzophenone (T/sub 1/BP) and its four isotopic analogues in carbon tetrachloride solutions were measured. Vibrational assignments of eight T/sub 1/ bands have been made on the basis of the observed isotopic frequency shifts. The assignments clarified the following three points concerning the structure of T/sub 1/ BP in solution. (1) The CO bond order in T/sub 1/ BP is much lower than that in the ground-state benzophenone (S/sub 0/ BP). The CO stretching frequency in T/sub 1/ is found to be 1222 cm/sup -1/, whereas the corresponding value in S/sub 0/ is 1665 cm/sup -1/. The former frequency indicates a single-bond-like character of the CO bonding in the T/sub 1/ state. (2) Vibrational frequencies of several ring modes show marked downshifts in going from S/sub 0/ to T/sub 1/. This suggests the delocalization of the ..pi..* electron into the ring part. (3) The assignment (1302 cm/sup -1/) of the symmetric C-phenyl stretch mode in the T/sub 1/ withdraws S/sub 0/ absorption spectrum is questioned. According to the present assignment, the frequency of this mode (approx. 1100 cm/sup -1/) is slightly lower than that in the ground state (1150 cm/sup -1/). The simple quantum chemical picture of T/sub 1/ BP, which predicted the increase of the C-phenyl bond order with the ..pi..* withdraws n excitation, should therefore be reconsidered.

  19. Fluorescence and picosecond induced absorption from the lowest singlet excited states of quercetin in solutions and polymer films

    NASA Astrophysics Data System (ADS)

    Bondarev, S. L.; Tikhomirov, S. A.; Buganov, O. V.; Knyukshto, V. N.; Raichenok, T. F.

    2017-03-01

    The spectroscopic and photophysical properties of the biologically important plant antioxidant quercetin in organic solvents, polymer films of polyvinyl alcohol, and a buffer solution at pH 7.0 are studied by stationary luminescence and femtosecond laser spectroscopy at room temperature and 77 K. The large magnitude of the dipole moment of the quercetin molecule in the excited Franck-Condon state μ e FC = 52.8 C m indicates the dipolar nature of quercetin in this excited state. The transient induced absorption spectra S 1→ S n in all solvents are characterized by a short-wave band at λ abs max = 460 nm with exponential decay times in the range of 10.0-20.0 ps. In the entire spectral range at times of >100 ps, no residual induced absorption was observed that could be attributed to the triplet-triplet transitions T 1 → T k in quercetin. In polar solvents, two-band fluorescence was also recorded at room temperature, which is due to the luminescence of the initial enol form of quercetin ( 415 nm) and its keto form with a transferred proton (550 nm). The short-wave band is absent in nonpolar 2-methyltetrahydrofuran (2-MTHF). The spectra of fluorescence and fluorescence excitation exhibit a low dependence on the wavelength of excitation and detection, which may be related to the solvation and conformational changes in the quercetin molecule. Decreasing the temperature of a glassy-like freezing quercetin solution in ethanol and 2-MTHF to 77 K leads to a strong increase in the intensity (by a factor of 100) of both bands. The energy circuits for the proton transfer process are proposed depending on the polarity of the medium. The main channel for the exchange of electronic excitation energy in the quercetin molecule at room temperature is the internal conversion S 1 ⇝ S 0, induced by the state with a proton transfer.

  20. g factors of the lowest (5/2)+ and (7/2)+ states in 197Au and calibration of the transient magnetic field in Gd

    NASA Astrophysics Data System (ADS)

    Bazzacco, D.; Brandolini, F.; Loewenich, K.; Pavan, P.; Rossi-Alvarez, C.; Zannoni, R.; de Poli, M.

    1986-05-01

    The angular precessions of the lowest (5/2)+ and (7/2)+ states in 197Au have been measured employing the transient field method. The 197Au nuclei, Coulomb-excited by a 180 MeV 63Cu beam, traversed the Gd foil with velocities between 5v0 and 2v0 (v0=c/137). We have obtained the values g((5/2)+)=0.21(2) and g((7/2)+)=0.15(2), which are consistent with the predictions of the particle-core weak-coupling model. The field has been calibrated with the Chalk River parametrization, which has been checked using the known g factors of the lowest 2+ states in 184W, 186W, 194Pt, and 196Pt as probes.

  1. UV-excited transient raman spectra and the co stretching frequencies of the lowest excited triplet state of benzophenone

    NASA Astrophysics Data System (ADS)

    Tahara, Tahei; Hamaguchi, Hiro-o.; Tasumi, Mitsuo

    1988-11-01

    Transient resonance Raman spectra of T 1 benzophenone (BP) and its carbonyl- 18O-substituted analogue were measured with 355 nm excitation which is in resonance with a triplet-triplet (T n←T 1) transition in the ultraviolet. The intensity of the CO stretch band was greatly enhanced under this resonance condition. Reliable values of the T 1 CO stretching frequency were obtained including the solvent shifts. It is concluded that the solvent dependence of the photochemical reactivity of BP is not primarily due to the solvent-induced structural changes in the T 1 state. The character of the two different T-T transitions (T n←T 1 and T n←T 1) is discussed in relation to the observed Raman spectral changes with different resonance conditions.

  2. Accurate evaluations of the field shift and lowest-order QED correction for the ground 1¹S-states of some light two-electron ions.

    PubMed

    Frolov, Alexei M; Wardlaw, David M

    2014-09-14

    Mass-dependent and field shift components of the isotopic shift are determined to high accuracy for the ground 1(1)S-states of some light two-electron Li(+), Be(2+), B(3+), and C(4+) ions. To determine the field components of these isotopic shifts we apply the Racah-Rosental-Breit formula. We also determine the lowest order QED corrections to the isotopic shifts for each of these two-electron ions.

  3. Incompressible Liquid State of Rapidly Rotating Bosons at Filling Factor 3/2

    SciTech Connect

    Rezayi, E.H.; Read, N.; Cooper, N.R.

    2005-10-14

    Bosons in the lowest Landau level, such as rapidly rotating cold trapped atoms, are investigated numerically in the specially interesting case in which the filling factor (ratio of particle number to vortex number) is 3/2. When a moderate amount of a longer-range (e.g., dipolar) interaction is included, we find clear evidence that the ground state is in a phase constructed earlier by two of us, in which excitations possess non-Abelian statistics.

  4. Molecular beam studies of weak interactions for open-shell systems: The ground and lowest excited states of rare gas oxides

    SciTech Connect

    Aquilanti, V.; Candori, R.; Pirani, F.

    1988-11-15

    Integral cross sections as a function of velocity for scattering of ground state oxygen atoms by the rare gases have been measured at thermal energy. Analysis of atomic sublevels by a Stern--Gerlach magnet allows a control of the relative contribution from different fine structure scattering channels. The results are analyzed using an adiabatic decoupling scheme to derive the interaction as a spherical part and an anisotropic component, from which information is obtained on the six lowest states of the rare gas oxides and on nonadiabatic coupling terms.

  5. Molecular beam studies of weak interactions for open-shell systems: The ground and lowest excited states of ArF, KrF, and XeF

    SciTech Connect

    Aquilanti, V.; Luzzatti, E.; Pirani, F.; Volpi, G.G.

    1988-11-15

    Absolute integral cross sections for scattering of ground state fluorine atoms by argon, krypton, and xenon have been measured in the thermal velocity range. Information has been obtained on the long range interaction and using a technique for magnetic analysis of substates of F atoms, a characterization is given for the bonding in the ground and the two lowest excited states of these rare gas fluorides. The potentials are represented as a spherical part and an anisotropic component, which have been obtained in an adiabatic decoupling treatment, including also information from other scattering data. Nonadiabatic coupling matrix elements and other general features of these interactions are also presented.

  6. Assignment of the lowest Qy-state and spectral dynamics of the CP29 chlorophyll a/b antenna complex of green plants: a hole-burning study.

    PubMed

    Pieper, J; Irrgang, K D; Rätsep, M; Voigt, J; Renger, G; Small, G J

    2000-05-01

    Low-temperature absorption, fluorescence and persistent non-photochemical hole-burned spectra are reported for the CP29 chlorophyll (Chl) a/b antenna complex of photosystem II of green plants. The absorption-origin band of the lowest Qy-state lies at 678.2 nm and carries a width of approximately 130 cm-1 that is dominated by inhomogeneous broadening at low temperatures. Its absorption intensity is equivalent to that of one of the six Chl a molecules of CP29. The absence of a significant satellite hole structure produced by hole burning, within the absorption band of the lowest state, indicates that the associated Chl a molecule is weakly coupled to the other Chl and, therefore, that the lowest-energy state is highly localized on a single Chl a molecule. The electron-phonon coupling of the 678.2 nm state is weak with a Huang-Rhys factor S of 0.5 and a peak phonon frequency (omega m) of approximately 20 cm-1. These values give a Stokes shift (2S omega m) in good agreement with the measured positions of the absorption band at 678.2 nm and a fluorescence-origin band at 679.1 nm. Zero-phonon holes associated with the lowest state have a width of approximately 0.05 cm-1 at 4.2 K, corresponding to a total effective dephasing time of approximately 400 ps. The temperature dependence of the zero-phonon holewidth indicates that this time constant is dominated at temperatures below 8 K by pure dephasing/spectral diffusion due to coupling of the optical transition to the glass-like two-level systems of the protein. Zero-phonon hole-widths obtained for the Chl b bands at 638.5 and 650.0 nm, at 4.2 K, lead to lower limits of 900 +/- 150 fs and 4.2 +/- 0.3 ps, respectively, for the Chl b-->Chl a energy-transfer times. Downward energy transfer from the Chl a state(s) at 665.0 nm occurs in 5.3 +/- 0.6 ps at 4.2 K.

  7. Lowest critical velocity of rotating shafts.

    NASA Technical Reports Server (NTRS)

    Atzori, B.; Curti, G.

    1973-01-01

    The effect of the gyroscopic moment on the appearance of a first imaginary critical velocity (minimum negative value of lambda) is investigated and shown to have an important effect on the computation of the first critical velocity. A numerical procedure is developed which can be used for overcoming the difficulties arising when the first real and the first imaginary roots are similar in modulus. As an example, a real shaft with two supports was analyzed. For the computation the real shaft was subdivided into ten sections, and for two of them (representing compressor and turbine) the gyroscopic moment was taken into account. The present method is especially useful when high speed computational facilities are not available.

  8. Reducing collective quantum state rotation errors with reversible dephasing

    SciTech Connect

    Cox, Kevin C.; Norcia, Matthew A.; Weiner, Joshua M.; Bohnet, Justin G.; Thompson, James K.

    2014-12-29

    We demonstrate that reversible dephasing via inhomogeneous broadening can greatly reduce collective quantum state rotation errors, and observe the suppression of rotation errors by more than 21 dB in the context of collective population measurements of the spin states of an ensemble of 2.1×10{sup 5} laser cooled and trapped {sup 87}Rb atoms. The large reduction in rotation noise enables direct resolution of spin state populations 13(1) dB below the fundamental quantum projection noise limit. Further, the spin state measurement projects the system into an entangled state with 9.5(5) dB of directly observed spectroscopic enhancement (squeezing) relative to the standard quantum limit, whereas no enhancement would have been obtained without the suppression of rotation errors.

  9. Optothermal spectroscopy of the dissociating lowest electronic singlet states of s-tetrazine and dimethyl-s-tetrazine in a molecular beam

    NASA Astrophysics Data System (ADS)

    Kerstel, E. R. Th.; Becucci, M.; Pietraperzia, G.; Castellucci, E.

    1997-01-01

    We report the spectra of the 000 bands of s-tetrazine and dimethyl-s-tetrazine in a seeded molecular beam, using optothermal detection. The S/N of the optothermal s-tetrazine spectrum is about 1000 times higher than that of the LIF spectrum recorded with the same machine. The depletion nature of the signals unequivocally establishes that both molecules dissociate before reaching the detector (i.e., within ˜0.5 ms) following excitation to the S1 state. The s-tetrazine spectrum is fit to an asymmetric rotor Hamiltonian that includes the observed interchange of the a and b inertial axis in the excited state. The rotational constants and the homogeneous line broadening of 215(10) MHz (FWHM) observed here are in good agreement with, but more accurate than, those obtained in earlier sub-Doppler (saturation) gas-cell and free-jet spectra. The spectrum of dimethyl-s-tetrazine is analyzed for the m=0 free-rotor states only. Its rotational lines require a Lorentzian component of 34(2) MHz, corresponding to an excited state lifetime of 4.7 ns. The relative efficiency of the dissociative and radiative decay channels is evaluated. Despite the fact that we believe we have sufficient sensitivity, we failed to observe the s-tetrazine T1 state at 735 nm, which may be evidence of its nondissociative character.

  10. Accurate evaluations of the field shift and lowest-order QED correction for the ground 1{sup 1}S−states of some light two-electron ions

    SciTech Connect

    Frolov, Alexei M.; Wardlaw, David M.

    2014-09-14

    Mass-dependent and field shift components of the isotopic shift are determined to high accuracy for the ground 1{sup 1}S−states of some light two-electron Li{sup +}, Be{sup 2+}, B{sup 3+}, and C{sup 4+} ions. To determine the field components of these isotopic shifts we apply the Racah-Rosental-Breit formula. We also determine the lowest order QED corrections to the isotopic shifts for each of these two-electron ions.

  11. Nuclear structure beyond the neutron drip line: The lowest energy states in 9He via their T = 5/2 isobaric analogs in 9Li

    NASA Astrophysics Data System (ADS)

    Uberseder, E.; Rogachev, G. V.; Goldberg, V. Z.; Koshchiy, E.; Roeder, B. T.; Alcorta, M.; Chubarian, G.; Davids, B.; Fu, C.; Hooker, J.; Jayatissa, H.; Melconian, D.; Tribble, R. E.

    2016-03-01

    The level structure of the very neutron rich and unbound 9He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy 9He states exist with spins Jπ = 1 /2+ and Jπ = 1 /2- and widths on the order of 100-200 keV. These findings cannot be reconciled with our contemporary understanding of nuclear structure. The present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the 8He+n system, performed via a search for the T = 5 / 2 isobaric analog states in 9Li populated through 8He+p elastic scattering. The present data show no indication of any narrow structures. Instead, we find evidence for a broad Jπ = 1 /2+ state in 9He located approximately 3 MeV above the neutron decay threshold.

  12. Temperature and solvent effects on the luminescence spectrum of C{sub 70}: Assignment of the lowest singlet and triplet states

    SciTech Connect

    Argentine, S.M.; Kotz, K.T.; Francis, A.H.

    1995-11-29

    The temperature, solvent, and concentration dependence of the fluorescence and phosphorescence spectra of C{sub 70} in glassy solutions have been examined. Spectra have been recorded over the temperature range 4-200 K. In addition, the AC Stark field modulated phosphorescence and the phosphorescence of {sup 13}C{sub 70} have been recorded and analyzed. The lowest triplet state is identified as a {sup 3}E{sub 1}` state and the vibronic structure consists primarily of Herzberg-Teller active e{sub 2}` modes. The intensity of the electronic origin is comparable to the vibronically induced intensity and is extraordinarily solvent sensitive. The solvent sensitivity exhibited by the spectra is shown to have the same origins as that observed in benzene and pyrene, but is several times greater in magnitude. Analysis of the spectra suggests that two electronic excited states contribute to the observed phosphorescence spectrum. 27 refs., 6 figs., 1 tab.

  13. Comparing Soil Carbon of Short Rotation Poplar Plantations with Agricultural Crops and Woodlots in North Central United States

    Treesearch

    Mark D. Coleman; J.G. Isebrands; David N. Tolsted; Virginia R. Tolbert

    2004-01-01

    We collected soil samples from 27 study sites across North Central United States to compare the soil carbon of short rotation poplar plantations to adjacent agricultural crops and woodlots. Soil organic carbon (SOC) ranged from 20 to more than 160 Mg/ha across the sampled sites. Lowest SOC levels were found in uplands and highest levels in riparian soils. We attributed...

  14. Rigid rotators. [deriving the time-independent energy states associated with rotational motions of the molecule

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The two-particle, steady-state Schroedinger equation is transformed to center of mass and internuclear distance vector coordinates, leading to the free particle wave equation for the kinetic energy motion of the molecule and a decoupled wave equation for a single particle of reduced mass moving in a spherical potential field. The latter describes the vibrational and rotational energy modes of the diatomic molecule. For fixed internuclear distance, this becomes the equation of rigid rotator motion. The classical partition function for the rotator is derived and compared with the quantum expression. Molecular symmetry effects are developed from the generalized Pauli principle that the steady-state wave function of any system of fundamental particles must be antisymmetric. Nuclear spin and spin quantum functions are introduced and ortho- and para-states of rotators, along with their degeneracies, are defined. Effects of nuclear spin on entropy are deduced. Next, rigid polyatomic rotators are considered and the partition function for this case is derived. The patterns of rotational energy levels for nonlinear molecules are discussed for the spherical symmetric top, for the prolate symmetric top, for the oblate symmetric top, and for the asymmetric top. Finally, the equilibrium energy and specific heat of rigid rotators are derived.

  15. Rigid rotators. [deriving the time-independent energy states associated with rotational motions of the molecule

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The two-particle, steady-state Schroedinger equation is transformed to center of mass and internuclear distance vector coordinates, leading to the free particle wave equation for the kinetic energy motion of the molecule and a decoupled wave equation for a single particle of reduced mass moving in a spherical potential field. The latter describes the vibrational and rotational energy modes of the diatomic molecule. For fixed internuclear distance, this becomes the equation of rigid rotator motion. The classical partition function for the rotator is derived and compared with the quantum expression. Molecular symmetry effects are developed from the generalized Pauli principle that the steady-state wave function of any system of fundamental particles must be antisymmetric. Nuclear spin and spin quantum functions are introduced and ortho- and para-states of rotators, along with their degeneracies, are defined. Effects of nuclear spin on entropy are deduced. Next, rigid polyatomic rotators are considered and the partition function for this case is derived. The patterns of rotational energy levels for nonlinear molecules are discussed for the spherical symmetric top, for the prolate symmetric top, for the oblate symmetric top, and for the asymmetric top. Finally, the equilibrium energy and specific heat of rigid rotators are derived.

  16. Rotational state detection of electrically trapped polyatomic molecules

    NASA Astrophysics Data System (ADS)

    Glöckner, Rosa; Prehn, Alexander; Rempe, Gerhard; Zeppenfeld, Martin

    2015-05-01

    Detecting the internal state of polar molecules is a substantial challenge when standard techniques such as resonance-enhanced multiphoton ionization or laser-induced fluorescense do not work. As this is the case for most polyatomic molecule species, in this paper we investigate an alternative based on state-selective removal of molecules from an electrically trapped ensemble. Specifically, we deplete molecules by driving rotational and/or vibrational transitions to untrapped states. Fully resolving the rotational state with this method can be a considerable challenge, as the frequency differences between various transitions are easily substantially less than the Stark broadening in an electric trap. However, by using a unique trap design that provides homogeneous fields in a large fraction of the trap volume, we successfully discriminate all rotational quantum numbers, including the rotational M-substate.

  17. Lowest excited states and optical absorption spectra of donor-acceptor copolymers for organic photovoltaics: a new picture emerging from tuned long-range corrected density functionals.

    PubMed

    Pandey, Laxman; Doiron, Curtis; Sears, John S; Brédas, Jean-Luc

    2012-11-07

    Polymers with low optical gaps are of importance to the organic photovoltaics community due to their potential for harnessing a large portion of the solar energy spectrum. The combination along their backbones of electron-rich and electron-deficient fragments contributes to the presence of low-lying excited states that are expected to display significant charge-transfer character. While conventional hybrid functionals are known to provide unsatisfactory results for charge-transfer excitations at the time-dependent DFT level, long-range corrected (LRC) functionals have been reported to give improved descriptions in a number of systems. Here, we use such LRC functionals, considering both tuned and default range-separation parameters, to characterize the absorption spectra of low-optical-gap systems of interest. Our results indicate that tuned LRC functionals lead to simulated optical-absorption properties in good agreement with experimental data. Importantly, the lowest-lying excited states (excitons) are shown to present a much more localized nature than initially anticipated.

  18. Ab - initio non-adiabatic couplings among three lowest singlet states of H3 +: Construction of multisheeted diabatic potential energy surfaces

    NASA Astrophysics Data System (ADS)

    Mukherjee, Bijit; Mukherjee, Saikat; Adhikari, Satrajit

    2016-10-01

    We calculate the adiabatic potential energy surfaces and non-adiabatic interactions among the three lowest singlet states (11 A', 21 A' and 31 A') of H3 + in hyperspherical coordinates for a fixed hyperradius, ρ = 9 bohr as functions of hyperangles, θ (0 < θ < 90°) and ϕ (0 < ϕ < 360°). All ab initio calculations are performed using MRCI level of methodology implemented in quantum chemistry package, MOLPRO. The ground (11 A') and the first excited (21 A') states exhibit several conical intersections as functions of ϕ for θ > 70°. Subsequently, we carry out adiabatic to diabatic transformation (ADT) to obtain ADT angles for constructing single-valued, continuous, smooth and symmetric 3 × 3 diabatic potential energy matrix to perform accurate scattering calculations.

  19. Photodissociation of CS2 in the vacuum ultraviolet - Determination of bond dissociation energy from the lowest vibrational level of the ground state CS2.

    NASA Technical Reports Server (NTRS)

    Okabe, H.

    1972-01-01

    Photolysis in the vacuum ultraviolet results almost exclusively in the production of S(super-3)P atoms, which is in apparent violation of spin conservation. The threshold energy of incident photons required to produce fluorescence was used to calculate the bond dissociation energy (from the lowest vibrational level of the ground state), and the result agrees with the value previously derived from the photoionization of CS2. The fluorescence excitation spectrum shows peaks corresponding to Rydberg series I and II, indicating that the observed photodissociation of CS2 in the vacuum ultraviolet is mainly the result of predissociation from Rydberg states. The absorption coefficient of CS2 was measured in the region of 1200 to 1400 A.

  20. Photoinduced omega-bond dissociation in the higher excited singlet (S2) and lowest triplet (T1) states of a benzophenone derivative in solution.

    PubMed

    Yamaji, Minoru; Inomata, Susumu; Nakajima, Satoru; Akiyama, Kimio; Tobita, Seiji; Marciniak, Bronislaw

    2005-05-05

    Photochemical properties of photoinduced omega-bond dissociation in p-benzoylbenzyl phenyl sulfide (BBPS) in solution were investigated by time-resolved EPR and laser flash photolysis techniques. BBPS was shown to undergo photoinduced omega-bond cleavage to yield the p-benzoylbenzyl radical (BBR) and phenyl thiyl radical (PTR) at room temperature. The quantum yield (phi(rad)) for the radical formation was found to depend on the excitation wavelength, i.e., on the excitation to the excited singlet states, S2 and S1 of BBPS; phi(rad)(S2) = 0.65 and phi(rad)(S1) = 1.0. Based on the CIDEP data, these radicals were found to be produced via the triplet state independent of excitation wavelength. By using triplet sensitization of xanthone, the efficiency (alpha(rad)) of the C-S bond fission in the lowest triplet state (T1) of BBPS was determined to be unity. The agreement between phi(rad)(S1) and alpha(rad) values indicates that the C-S bond dissociation occurs in the T1 state via the S1 state due to a fast intersystem crossing from the S1 to the T1 state. In contrast, the wavelength dependence of the radical yields was interpreted in terms of the C-S bond cleavage in the S2 state competing with internal conversion from the S2 to the S1 state. The smaller value of phi(rad)(S2) than that of phi(rad)(S1) was proposed to originate from the geminate recombination of singlet radical pairs produced by the bond dissociation via the S2 state. Considering the electronic character of the excited and dissociative states in BBPS showed a schematic energy diagram for the omega-bond dissociation of BBPS.

  1. Determination of the Lowest-Energy States for the Model Distribution of Trained Restricted Boltzmann Machines Using a 1000 Qubit D-Wave 2X Quantum Computer.

    PubMed

    Koshka, Yaroslav; Perera, Dilina; Hall, Spencer; Novotny, M A

    2017-07-01

    The possibility of using a quantum computer D-Wave 2X with more than 1000 qubits to determine the global minimum of the energy landscape of trained restricted Boltzmann machines is investigated. In order to overcome the problem of limited interconnectivity in the D-Wave architecture, the proposed RBM embedding combines multiple qubits to represent a particular RBM unit. The results for the lowest-energy (the ground state) and some of the higher-energy states found by the D-Wave 2X were compared with those of the classical simulated annealing (SA) algorithm. In many cases, the D-Wave machine successfully found the same RBM lowest-energy state as that found by SA. In some examples, the D-Wave machine returned a state corresponding to one of the higher-energy local minima found by SA. The inherently nonperfect embedding of the RBM into the Chimera lattice explored in this work (i.e., multiple qubits combined into a single RBM unit were found not to be guaranteed to be all aligned) and the existence of small, persistent biases in the D-Wave hardware may cause a discrepancy between the D-Wave and the SA results. In some of the investigated cases, introduction of a small bias field into the energy function or optimization of the chain-strength parameter in the D-Wave embedding successfully addressed difficulties of the particular RBM embedding. With further development of the D-Wave hardware, the approach will be suitable for much larger numbers of RBM units.

  2. Presence of two emissive minima in the lowest excited state of a push-pull cationic dye unequivocally proved by femtosecond up-conversion spectroscopy and vibronic quantum-mechanical computations.

    PubMed

    Benassi, Enrico; Carlotti, Benedetta; Segado, Mireia; Cesaretti, Alessio; Spalletti, Anna; Elisei, Fausto; Barone, Vincenzo

    2015-05-14

    The long-standing controversy about the presence of two different emissive minima in the lowest excited state of the cationic push-pull dye o-(p-dimethylamino-styryl)-methylpyridinium (DASPMI) was definitively proved through the observation of dual emission, evidenced by both experimental (femtosecond up-conversion measurements) and theoretical (density functional theory calculations) approaches. From the fluorescence up-conversion data of DASPMI in water, the time resolved area normalized spectra (TRANES) were calculated, showing one isoemissive point and therefore revealing the presence of two distinct emissive minima of the excited state potential energy hypersurface with lifetimes of 0.51 and 4.8 ps. These spectroscopic techniques combined with proper data analysis allowed us to discriminate the sub-picosecond emitting state from the occurrence of ultrafast solvation dynamics and to disentangle the overlapping fluorescence (very close in energy) of the two components. Vibronic computations based on TD-DFT potential energy surfaces fully confirm those results and provide deeper insights about the key factors playing a role in determining the overall result. The two emissive minima have different structural and electronic characteristics: on one hand, the locally excited (LE) minimum has a flat geometry and an electric dipole moment smaller than the ground state; on the other hand, the twisted-intramolecular-charge-transfer (TICT) minimum shows a rotation of the methylpyridinium moiety with respect to the rest of the structure, and has an electric dipole moment significantly larger than the ground state.

  3. Optical cooling of AlH+ to the rotational ground state

    NASA Astrophysics Data System (ADS)

    Lien, Chien-Yu; Seck, Christopher; Odom, Brian

    2014-05-01

    We demonstrate cooling of the rotational degree of freedom of trapped diatomic molecular ions to the rotational ground state. The molecule of interested, AlH+, is co-trapped and sympathetically cooled with Ba+ to milliKelvin temperatures in its translational degree of freedom. The nearly diagonal Franck-Condon-Factors between the electronic X and A states of AlH+ create semi-closed cycling transitions between the vibrational ground states of X and A states. A spectrally filtered femtosecond laser is used to optically pump the population to the two lowest rotational levels, with opposite parities, in as fast as 100 μs via driving the A-X transition. In addition, a cooling scheme relying on vibrational relaxation brings the population to the N = 0 positive-parity level in as fast as 100 ms. The population distribution among the rotational levels is detected by resonance-enhanced multiphoton dissociation (REMPD) and time-of-flight mass-spectrometry (TOFMS). Although the current two-photon state readout scheme is destructive, a scheme of single-molecule fluorescence detection is also considered.

  4. Favorable performance of the DFT methods in predicting the minimum-energy structure of the lowest triplet state of WF{sub 4}

    SciTech Connect

    Gutowski, M. |

    1999-06-15

    The tetrahedral structure of the lowest triplet state of the WF{sub 4} complex was examined using different variants of the density functional theory (DFT) and conventional ab initio methods. The low-level, conventional, ab initio methods, such as SCF, MP2, MP3, and CISD, predict the tetrahedral structure to be a minimum, whereas the DFT schemes predict an imaginary frequency for the e vibrational mode. Only after recovering electron correlation effects at the MP4 and higher levels, the conventional electronic structure methods also predict the T{sub d} structure to be a second-order stationary point. This is not the correlation but the exchange part of the DFT functionals which is responsible for the discrepancy between the DFT and low-level, conventional, ab initio predictions. The lowering of symmetry to C{sub 2v} leads to a minimum on the lowest triplet potential energy surface and the electronic energy difference between the T{sub d} and C{sub 2v} stationary points amounts to 0.85 and 0.96 kcal/mol at the B3LYP and CCSD(T) levels, respectively.

  5. Lowest lying 2{sup +} and 3{sup -} vibrational states in Pb, Sn, and Ni isotopes in relativistic quasiparticle random-phase approximation

    SciTech Connect

    Ansari, A.; Ring, P.

    2006-11-15

    The excitation energies and electric multipole decay rates of the lowest lying 2{sup +} and 3{sup -} vibrational states in Pb, Sn, and Ni nuclei are calculated following relativistic quasiparticle random-phase approximation formalism based on the relativistic Hartree-Bogoliubov mean field. Two sets of Lagrangian parameters, NL1 and NL3, are used to investigate the effect of the nuclear force. Overall there is good agreement with the available experimental data for a wide range of mass numbers considered here, and the NL3 set seems to be a better choice. However, strictly speaking, these studies point toward the need of a new set of force parameters that could produce more realistic single-particle levels, at least in vicinity of the Fermi surface, of a wide range of nuclear masses.

  6. Measurement of the 14N nuclear quadrupole couplings in the lowest (nπ *) excited triplet state of pyrazine by ODMR

    NASA Astrophysics Data System (ADS)

    Fröhling, W.; Winscom, C. J.; Möbius, K.

    1983-03-01

    High-resolution optically detected magnetic resonance (ODMR) and optically detected electron—electron double resonance (ODEEDOR) have been performed on the lowest excited triplet states of pyrazine- h4 and pyrazine- d4, as dilute guests in polycrystalline benzene and cyclohexane host matrices. Computer simulated spectra have been fitted to those experimentally observed, using a spin hamiltonian which takes into account the 14N and 1H (or 2D) nuclei of the pyrazine guest molecule. Good agreement is obtained when one 14N nuclear quadrupole energy difference, |ɛ yN - ɛ zN| ⩽ 1.3 MHz, and the remaining component, |ɛ xN| = 0.6 ± 0.2 MHz for pyrazine- d4 in benzene- d6.

  7. Full-dimensional MCTDH/MGPF study of the ground and lowest lying vibrational states of the bihydroxide H3O2(-) complex.

    PubMed

    Peláez, Daniel; Sadri, Keyvan; Meyer, Hans-Dieter

    2014-02-05

    In this study, we present a full-dimensional (9D) quantum dynamical analysis of the lowest vibrational eigenstates of H3O2(-). We have made use of the Multiconfiguration Time-Dependent Hartree method in conjunction with both an analytical and a numerical representation of the Kinetic Energy Operator and the newly developed Multigrid POTFIT [D. Peláez, H.-D. Meyer, J. Chem. Phys. 138 (2013) 014108], an algorithm which performs the transformation of a high-dimensional (up to ~12D) Potential Energy tensor into product form. Many sets of top-down Multigrid POTFIT expansions, differing in the system coordinate definition (valence and Jacobi), as well as in the number of terms in the expansion, have been analyzed. Relaxations for the computation of the ground states energies have been carried out on these potentials, obtaining an excellent overall agreement with accurate previous Diffusion Monte Carlo (DMC) calculations, irrespective of the coordinate choice. The 24 lowest excited vibrational states of H3O2(-) have been computed by Block Relaxation and assigned for the first time. This has been carried out in two different pictures, namely: a 7D reduced dimensional one, in which the OH distances have been frozen at the Potential Energy Surface minimum, and a 9D full-dimensional one. The agreement between both descriptions is remarkable. The following fundamental modes have been characterized: OH torsion, OO stretching, OH wagging, OH rocking, and the elusive bridging H stretching. In particular, we provide a very accurate description of the latter in perfect agreement with experiment.

  8. Rotational transition states: relative equilibrium points in inelastic molecular collisions

    NASA Astrophysics Data System (ADS)

    Wiesenfeld, L.; Faure, A.; Johann, T.

    2003-04-01

    Transition states (TSs) are a key ingredient in the understanding of many chemical reactions. We present here a generalization of TS theory towards rotational excitation in molecular collisions, in a multi-dimensional classical Hamiltonian framework. The treatment is based on relative equilibrium, where the two colliding molecules behave as a single rotating solid object. We illustrate the theory with the help of a simple, yet meaningful, model potential for collisions between H2O and H2, which is of great importance in the astrophysical context. We show that it is the occurrence of a rotational TS that opens up the possibility of significant angular momentum transfer.

  9. Magnesium(II) and zinc(II)-protoporphyrin IX's stabilize the lowest oxygen affinity state of human hemoglobin even more strongly than deoxyheme.

    PubMed

    Miyazaki, G; Morimoto, H; Yun, K M; Park, S Y; Nakagawa, A; Minagawa, H; Shibayama, N

    1999-10-08

    Studies of oxygen equilibrium properties of Mg(II)-Fe(II) and Zn(II)-Fe(II) hybrid hemoglobins (i.e. alpha2(Fe)beta2(M) and alpha2(M)beta2(Fe); M=Mg(II), Zn(II) (neither of these closed-shell metal ions binds oxygen or carbon monoxide)) are reported along with the X-ray crystal structures of alpha2(Fe)beta2(Mg) with and without CO bound. We found that Mg(II)-Fe(II) hybrids resemble Zn(II)-Fe(II) hybrids very closely in oxygen equilibrium properties. The Fe(II)-subunits in these hybrids bind oxygen with very low affinities, and the effect of allosteric effectors, such as proton and/or inositol hexaphosphate, is relatively small. We also found a striking similarity in spectrophotometric properties between Mg(II)-Fe(II) and Zn(II)-Fe(II) hybrids, particularly, the large spectral changes that occur specifically in the metal-containing beta subunits upon the R-T transition of the hybrids. In crystals, both alpha2(Fe)beta2(Mg) and alpha2(Fe-CO)beta2(Mg) adopt the quaternary structure of deoxyhemoglobin. These results, combined with the re-evaluation of the oxygen equilibrium properties of normal hemoglobin, low-affinity mutants, and metal substituted hybrids, point to a general tendency of human hemoglobin that when the association equilibrium constant of hemoglobin for the first binding oxygen molecule (K1) approaches 0.004 mmHg(-1), the cooperativity as well as the effect of allosteric effectors is virtually abolished. This is indicative of the existence of a distinct thermodynamic state which determines the lowest oxygen affinity of human hemoglobin. Moreover, excellent agreement between the reported oxygen affinity of deoxyhemoglobin in crystals and the lowest affinity in solution leads us to propose that the classical T structure of deoxyhemoglobin in the crystals represents the lowest affinity state in solution. We also survey the oxygen equilibrium properties of various metal-substituted hybrid hemoglobins studied over the past 20 years in our laboratory. The bulk

  10. Isotope shifts of the three lowest 1S states of the B+ ion calculated with a finite-nuclear-mass approach and with relativistic and quantum electrodynamics corrections.

    PubMed

    Bubin, Sergiy; Komasa, Jacek; Stanke, Monika; Adamowicz, Ludwik

    2010-03-21

    We present very accurate quantum mechanical calculations of the three lowest S-states [1s(2)2s(2)((1)S(0)), 1s(2)2p(2)((1)S(0)), and 1s(2)2s3s((1)S(0))] of the two stable isotopes of the boron ion, (10)B(+) and (11)B(+). At the nonrelativistic level the calculations have been performed with the Hamiltonian that explicitly includes the finite mass of the nucleus as it was obtained by a rigorous separation of the center-of-mass motion from the laboratory frame Hamiltonian. The spatial part of the nonrelativistic wave function for each state was expanded in terms of 10,000 all-electron explicitly correlated Gaussian functions. The nonlinear parameters of the Gaussians were variationally optimized using a procedure involving the analytical energy gradient determined with respect to the nonlinear parameters. The nonrelativistic wave functions of the three states were subsequently used to calculate the leading alpha(2) relativistic corrections (alpha is the fine structure constant; alpha=1/c, where c is the speed of light) and the alpha(3) quantum electrodynamics (QED) correction. We also estimated the alpha(4) QED correction by calculating its dominant component. A comparison of the experimental transition frequencies with the frequencies obtained based on the energies calculated in this work shows an excellent agreement. The discrepancy is smaller than 0.4 cm(-1).

  11. Nuclear structure beyond the neutron drip line. The lowest energy states in 9He via their T=5/2 isobaric analogs in 9Li

    DOE PAGES

    Uberseder, E.; Rogachev, G. V.; Goldberg, V. Z.; ...

    2016-03-01

    The level structure of the very neutron rich and unbound 9He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy 9He states exist with spins Jπ=1/2+and Jπ=1/2-and widths on the order of 100–200 keV. These find-ings cannot be reconciled with our contemporary understanding of nuclear structure. Our present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the 8He+n system, performed via a search for the T =5/2 isobaric analog states in 9Li populated through 8He+p elastic scattering. Moreover, themore » present data show no indication of any narrow structures. Instead, we find evidence for a broad Jπ=1/2+state in 9He located approximately 3 MeV above the neutron decay threshold.« less

  12. Rotational state dependence of fluorescence from S 1 pyrazine: evidence for the role of spin-orbit-orbital rotation interaction

    NASA Astrophysics Data System (ADS)

    Terazima, Masahide; Lim, E. C.

    1986-06-01

    Experimental and computer simulation studies of the "biexponential fluorescence" from jet-cooled S 1 pyrazine indicate that the rotational state dependence of the Afast/ Aslow ratio has its primary origin in the spin-orbit-orbital rotational interactions.

  13. Experimental determination of rotational constants of low-lying vibrational levels in the 0g- pure long-range state of ultracold Cs2 molecule

    NASA Astrophysics Data System (ADS)

    Wu, Jizhou; Liu, Wenliang; Li, Yuqing; Ma, Jie; Xiao, Liantuan; Jia, Suotang

    2017-04-01

    We report an accurate experimental determination of rotational constants of the lowest vibrational levels in the purely long-range state of ultracold cesium molecules (Cs2). We engineer a precise reference of the frequency difference through double photoassociation spectroscopy (PAS). The PAS for the lowest vibrational levels, v=0-3, has been obtained with an enhanced sensitivity and accuracy, according to which the binding energies have been corrected. As deduced from the reference, the frequency intervals between neighboring rotational levels are fitted to a non-rigid rotor model, thus the rotational constants are precisely obtained. The experimental results show good agreement with theoretical expectations.

  14. Rotational Spectra in 29 Vibrationally Excited States of Interstellar Aminoacetonitrile

    NASA Astrophysics Data System (ADS)

    Kolesniková, L.; Alonso, E. R.; Mata, S.; Alonso, J. L.

    2017-04-01

    We report a detailed spectroscopic investigation of the interstellar aminoacetonitrile, a possible precursor molecule of glycine. Using a combination of Stark and frequency-modulation microwave and millimeter wave spectroscopies, we observed and analyzed the room-temperature rotational spectra of 29 excited states with energies up to 1000 cm‑1. We also observed the 13C isotopologues in the ground vibrational state in natural abundance (1.1%). The extensive data set of more than 2000 new rotational transitions will support further identifications of aminoacetonitrile in the interstellar medium.

  15. Laboratory rotational ground state transitions of NH3D+ and CF+

    NASA Astrophysics Data System (ADS)

    Stoffels, A.; Kluge, L.; Schlemmer, S.; Brünken, S.

    2016-09-01

    Aims: This paper reports accurate laboratory frequencies of the rotational ground state transitions of two astronomically relevant molecular ions, NH3D+ and CF+. Methods: Spectra in the millimetre-wave band were recorded by the method of rotational state-selective attachment of He atoms to the molecular ions stored and cooled in a cryogenic ion trap held at 4 K. The lowest rotational transition in the A state (ortho state) of NH3D+ (JK = 10-00), and the two hyperfine components of the ground state transition of CF+ (J = 1-0) were measured with a relative precision better than 10-7. Results: For both target ions, the experimental transition frequencies agree with recent observations of the same lines in different astronomical environments. In the case of NH3D+ the high-accuracy laboratory measurements lend support to its tentative identification in the interstellar medium. For CF+ the experimentally determined hyperfine splitting confirms previous quantum-chemical calculations and the intrinsic spectroscopic nature of a double-peaked line profile observed in the J = 1-0 transition towards the Horsehead photon-dominated region (PDR).

  16. Lowest triplet (n,π*) state of 2-cyclohexen-1-one: Characterization by cavity ringdown spectroscopy and quantum-chemical calculations

    NASA Astrophysics Data System (ADS)

    McAnally, Michael O.; Zabronsky, Katherine L.; Stupca, Daniel J.; Phillipson, Kaitlyn; Pillsbury, Nathan R.; Drucker, Stephen

    2013-12-01

    The cavity ringdown (CRD) absorption spectrum of 2-cyclohexen-1-one (2CHO) was recorded over the range 401.5-410.5 nm in a room-temperature gas cell. The very weak band system (ɛ ⩽ 0.1 M-1 cm-1) in this spectral region is due to the T1(n, π*) ← S0 electronic transition. The 0^0_0 origin band was assigned to the feature observed at 24 558.8 ± 0.3 cm-1. We have assigned 46 vibronic transitions in a region extending from -200 to +350 cm-1 relative to the origin band. For the majority of these transitions, we have made corresponding assignments in the spectrum of the deuterated derivative 2CHO-2,6,6-d3. From the assignments, we determined fundamental frequencies for several vibrational modes in the T1(n, π*) excited state of 2CHO, including the lowest ring-twisting (99.6 cm-1) and ring-bending (262.2 cm-1) modes. These values compare to fundamentals of 122.2 cm-1 and 251.9 cm-1, respectively, determined previously for the isoconfigurational S1(n, π*) excited state of 2CHO and 99 cm-1 and 248 cm-1, respectively, for the S0 ground state. With the aid of quantum-mechanical calculations, we have also ascertained descriptions for these two modes, thereby resolving ambiguities appearing in the previous literature. The ring-twisting mode (ν39) contains a significant contribution from O=C-C=C torsion, whereas the ring-bending mode (ν38 in the ground state) involves mainly the motion of C-5 with respect to the plane containing the other heavy atoms. The CRD spectroscopic data for the T1(n, π*) state have allowed us to benchmark several computational methods for treating excited states, including time-dependent density functional theory and an equation-of-motion coupled cluster method. In turn, the computational results provide an explanation for observed differences in the T1(n, π*) vs. S1(n, π*) ring frequencies.

  17. Lowest triplet (n,π{sup *}) state of 2-cyclohexen-1-one: Characterization by cavity ringdown spectroscopy and quantum-chemical calculations

    SciTech Connect

    McAnally, Michael O.; Zabronsky, Katherine L.; Stupca, Daniel J.; Phillipson, Kaitlyn; Pillsbury, Nathan R.; Drucker, Stephen

    2013-12-07

    The cavity ringdown (CRD) absorption spectrum of 2-cyclohexen-1-one (2CHO) was recorded over the range 401.5–410.5 nm in a room-temperature gas cell. The very weak band system (ε ⩽ 0.1 M{sup −1} cm{sup −1}) in this spectral region is due to the T{sub 1}(n, π*) ← S{sub 0} electronic transition. The 0{sub 0}{sup 0} origin band was assigned to the feature observed at 24 558.8 ± 0.3 cm{sup −1}. We have assigned 46 vibronic transitions in a region extending from −200 to +350 cm{sup −1} relative to the origin band. For the majority of these transitions, we have made corresponding assignments in the spectrum of the deuterated derivative 2CHO-2,6,6-d{sub 3}. From the assignments, we determined fundamental frequencies for several vibrational modes in the T{sub 1}(n, π{sup *}) excited state of 2CHO, including the lowest ring-twisting (99.6 cm{sup −1}) and ring-bending (262.2 cm{sup −1}) modes. These values compare to fundamentals of 122.2 cm{sup −1} and 251.9 cm{sup −1}, respectively, determined previously for the isoconfigurational S{sub 1}(n, π{sup *}) excited state of 2CHO and 99 cm{sup −1} and 248 cm{sup −1}, respectively, for the S{sub 0} ground state. With the aid of quantum-mechanical calculations, we have also ascertained descriptions for these two modes, thereby resolving ambiguities appearing in the previous literature. The ring-twisting mode (ν{sub 39}) contains a significant contribution from O=C–C=C torsion, whereas the ring-bending mode (ν{sub 38} in the ground state) involves mainly the motion of C-5 with respect to the plane containing the other heavy atoms. The CRD spectroscopic data for the T{sub 1}(n, π{sup *}) state have allowed us to benchmark several computational methods for treating excited states, including time-dependent density functional theory and an equation-of-motion coupled cluster method. In turn, the computational results provide an explanation for observed differences in the T{sub 1}(n,

  18. Temperature dependence of the lowest excited singlet-state lifetime of all- trans -. beta. -carotene and fully deuterated all- trans -. beta. -carotene

    SciTech Connect

    Wasielewski, M.R.; Johnson, D.G. ); Bradford, E.G.; Kispert, L.D. )

    1989-12-01

    A 4 ps, 450 nm laser pulse was used to electronically excite all-{ital trans}-{beta}-carotene and all-{ital trans}-{beta}-carotene-{ital d}{sub 56} in 3-methylpentane. The transient absorption spectra of these molecules were measured as a function of temperature down to 20 K. In all cases the 400--500 nm electronic absorption band of each carotene bleaches and a new absorption band near 560 nm appears immediately upon excitation. These bands recover with single exponential kinetics: {tau}=8.1{plus minus}0.5 ps for all-{ital trans}-{beta}-carotene, and {tau}=10.5{plus minus}0.6 ps for all-{ital trans}-{beta}-carotene-{ital d}{sub 56} at 294 K. These recovery times increase by about a factor of 2 in glassy 3-methylpentane, and are nearly independent of temperature from 100 to 20 K. The weak dependencies of the lowest excited single-state lifetime of all-{ital trans}-{beta}-carotene on deuteration and temperature are discussed in terms of nonradiative decay mechanisms within carotenoids.

  19. Optical and magnetic properties of the lowest triplet state of pyrido(2,3-b)pyrazine. An example of /sup 3/n. pi. * azanaphthalene

    SciTech Connect

    Yamauchi, S.; Hirota, N.

    1987-03-26

    The lowest excited triplet (T/sub 1/) states of pyrido(2,3-b)pyrazine(2,3-b)pyrazine (PP; 1,4,5-triazanaphthalene) in the three kinds of environments have been studied by using various spectroscopic and magnetic resonance techniques. The authors obtained phosphorescence emission and excitation spectra, triplet lifetimes, zero field splittings (zfs), and triplet sublevel properties. From the analysis of the results the authors conclude that T/sub 1/ is /sup 3/n..pi..* in character in a single crystal of durene and in ethanol, but it is /sup 3/..pi pi..* in trifluoroethanol. Observation of the /sup 3/n..pi..* phosphoresence was made for the first time in azanaphthalenes, which provides direct information about /sup 3/n..pi..* azanaphthalene. The 0-0 band and vibronic bands involving a' vibrations are dominant in the phosphorescence spectrum. Large zfs and negative D (identical with -3/2X; -3.1 GHz) were obtained. As for the sublevel properties T/sub z/ is the most active and T/sub x/ is inactive in both radiative and nonradiative processes, whereas T/sub y/ is moderately active in the T/sub 1/ approx...-->.. S/sub 0/ nonradiative decay process. These /sup 3/n..pi..* properties were discussed in comparison with those of /sup 3/..pi pi..* PP and azanaphtalenes and numbern..pi..* azabenzenes. Possible mechanisms to explain the radiative and nonradiative properties are given.

  20. High resolution infrared spectrum of the CD2 wagging band of methanol-D2 (CHD2OH) for the lowest lying torsional vibrational state (e0)

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Indra

    2016-07-01

    This paper reports the analysis of the high resolution (0.0019 cm-1) Fourier transform infrared (FTIR) spectrum for asymmetrically deuterated methanol CHD2OH (methanol-D2) at a low temperature for the CD2 wagging band for the lowest lying trans-species (e0). In spite of the complexity and perturbation in the spectra, assignments were possible for the CD2 wagging band for a maximum K value of 10. In total, about 500 spectral lines have been assigned. Analysis of the spectral lines has been performed in terms of state dependent molecular parameters, Q-branch origins and asymmetry splitting. Assignments have been thoroughly confirmed using combination relations (see text). The catalogue of the assigned transition wavenumbers will help identification and prediction of far infrared (FIR) optically pumped CO2 lasers. The absorption lines close to the several 10R and 10P CO2 laser lines have also been identified. These should help experimentalists to optimize the power of the emission FIR laser lines and to predict new lines and should prove valuable as a laboratory support for interstellar detection in "Radio Astronomy". To our knowledge this is the first time such vibrational infrared (IR) high resolution study in CHD2OH is being performed.

  1. State to state He-CO rotationally inelastic scattering

    NASA Astrophysics Data System (ADS)

    Antonova, Stiliana; Lin, Ao; Tsakotellis, Antonis P.; McBane, George C.

    1999-02-01

    Relative integral cross sections for rotational excitation of CO in collisions with He were measured at energies of 72 and 89 meV. The cross sections are sensitive to anisotropy in the repulsive wall of the He-CO interaction. The experiments were done in crossed molecular beams with resonance enhanced multiphoton ionization detection. The observed cross sections display interference structure at low Δj, despite the average over the initial CO rotational distribution. At higher Δj, the cross sections decrease smoothly. The results are compared with cross sections calculated from two high quality potential energy surfaces for the He-CO interaction. The ab initio SAPT surface of Heijmen et al. [J. Chem. Phys. 107, 9921 (1997)] agrees with the data better than the XC(fit) surface of Le Roy et al. [Farad. Disc. 97, 81 (1994)].

  2. Zethrene biradicals: How pro-aromaticity is expressed in the ground electronic state and in the lowest energy singlet, triplet, and ionic states

    SciTech Connect

    Zafra, José Luis; González Cano, Rafael C.; Ruiz Delgado, M. Carmen; López Navarrete, Juan T.; Casado, Juan

    2014-02-07

    A analysis of the electronic and molecular structures of new molecular materials based on zethrene is presented with particular attention to those systems having a central benzo-quinoidal core able to generate Kekulé biradicals whose stability is provided by the aromaticity recovery in this central unit. These Kekulé biradicals display singlet ground electronic states thanks to double spin polarization and have low-energy lying triplet excited states also featured by the aromaticity gain. Pro-aromatization is also the driving force for the stabilization of the ionized species. Moreover, the low energy lying singlet excited states also display a profound biradical fingerprint allowing to singlet exciton fission. These properties are discussed in the context of the size of the zethrene core and of its substitution. The work encompasses all known long zethrenes and makes use of a variety of experimental techniques, such as Raman, UV-Vis-NIR absorption, transient absorption, in situ spectroelectrochemistry and quantum chemical calculations. This study reveals how the insertion of suitable molecular modules (i.e., quinoidal) opens the door to new intriguing molecular properties exploitable in organic electronics.

  3. Zethrene biradicals: how pro-aromaticity is expressed in the ground electronic state and in the lowest energy singlet, triplet, and ionic states.

    PubMed

    Zafra, José Luis; González Cano, Rafael C; Ruiz Delgado, M Carmen; Sun, Zhe; Li, Yuan; López Navarrete, Juan T; Wu, Jishan; Casado, Juan

    2014-02-07

    A analysis of the electronic and molecular structures of new molecular materials based on zethrene is presented with particular attention to those systems having a central benzo-quinoidal core able to generate Kekulé biradicals whose stability is provided by the aromaticity recovery in this central unit. These Kekulé biradicals display singlet ground electronic states thanks to double spin polarization and have low-energy lying triplet excited states also featured by the aromaticity gain. Pro-aromatization is also the driving force for the stabilization of the ionized species. Moreover, the low energy lying singlet excited states also display a profound biradical fingerprint allowing to singlet exciton fission. These properties are discussed in the context of the size of the zethrene core and of its substitution. The work encompasses all known long zethrenes and makes use of a variety of experimental techniques, such as Raman, UV-Vis-NIR absorption, transient absorption, in situ spectroelectrochemistry and quantum chemical calculations. This study reveals how the insertion of suitable molecular modules (i.e., quinoidal) opens the door to new intriguing molecular properties exploitable in organic electronics.

  4. An efficient magic state approach to small angle rotations

    NASA Astrophysics Data System (ADS)

    Campbell, Earl T.; O'Gorman, Joe

    2016-12-01

    Standard error-correction techniques only provide a quantum memory and need extra gadgets to perform computation. Central to quantum algorithms are small angle rotations, which can be fault-tolerantly implemented given a supply of an unconventional species of magic state. We present a low-cost distillation routine for preparing these small angle magic states. Our protocol builds on the work of Duclos-Cianci and Poulin (2015 Phys. Rev. A 91 042315) by compressing their circuit. Additionally, we present a method of diluting magic states that reduces costs associated with very small angle rotations. We quantify performance by the expected number of noisy magic states consumed per rotation, and compare with other protocols. For modest-sized angles, our protocols offer a factor 24 improvement over the best-known gate synthesis protocols and a factor 2 over the Duclos-Cianci and Poulin protocol. For very small angle rotations, the dilution protocol dramatically reduces costs, giving several orders magnitude improvement over competitors. There also exists an intermediary regime of small, but not very small, angles where our approach gives a marginal improvement over gate synthesis. We discuss how different performance metrics may alter these conclusions.

  5. Rotational and rotationless states of weakly bound molecules

    SciTech Connect

    Lemeshko, Mikhail; Friedrich, Bretislav

    2009-05-15

    By making use of the quantization rule of Raab and Friedrich [Phys. Rev. A 78, 022707 (2008)], we derive simple and accurate formulae for the number of rotational states supported by a weakly bound vibrational level of a diatomic molecule and the rotational constants of any such levels up to the threshold, and provide a criterion for determining whether a given weakly bound vibrational level is rotationless. The results depend solely on the long-range part of the molecular potential and are applicable to halo molecules.

  6. Rotation-vibration states of H3+ at dissociation

    NASA Astrophysics Data System (ADS)

    Kostin, Maxim A.; Polyansky, Oleg L.; Tennyson, Jonathan; Mussa, Hamse Y.

    2003-02-01

    Calculations are presented which estimate energies for all the bound rotation-vibration energy levels of H3+ with rotation angular momentum J=0, 2 and 8. The calculations, which use Radau coordinates with z-axis of the molecule embedded perpendicular to the molecular plane, are performed on 128 nodes of a massively parallel computer. It is found that convergence with respect to basis set size of the higher J states is fairly slow and that further improvements are beyond the capabilities of the current computational set-up.

  7. A theoretical study of the ground state and lowest excited states of PuO0/+/+2 and PuO20/+/+2

    SciTech Connect

    Gibson, John K.; La Macchia, Giovanni; Infante, Ivan; Gagliardi, Laura; Raab, Juraj

    2008-12-08

    The ground and excited states of neutral and cationic PuO and PuO2 have been studied with multiconfigurational quantum chemical methods followed by second order perturbation theory, the CASSCF/CASPT2 method. Scalar relativistic effects and spin-orbit coupling have been included in the treatment. As literature values for the ionization energy of PuO2 are in the wide range of ~;;6.6 eV to ~;;10.1 eV, a central goal of the computations was to resolve these discrepancies; the theoretical results indicate that the ionization energy is near the lower end of this range. The calculated ionization energies for PuO, PuO+ and PuO2+ are in good agreement with the experimental values.

  8. Probable Rotation States of Rocket Bodies in Low Earth Orbit

    NASA Astrophysics Data System (ADS)

    Ojakangas, G.; Anz-Meador, P.; Cowardin, H.

    2012-09-01

    In order for Active Debris Removal to be accomplished, it is critically important to understand the probable rotation states of orbiting, spent rocket bodies (RBs). However, rotational dynamics is non-intuitive and misconceptions are common. Determinations of rotation and precession rates from light curves have been published that are inconsistent with the theory presented here. In a state of free precession, the total angular momentum of the object is constant, while kinetic energy decreases due to internal friction, approaching rotation about the axis of maximum inertia. For solid internal friction the timescale is hundreds to thousands of years for quality factors of ~100 and assuming metallic rigidities, but for friction in partially-filled liquid fuel tanks we predict that the preferred rotational state is approached rapidly, within days to months. However, history has shown that theoretical predictions of the timescale have been notoriously inaccurate. In free precession, the 3-1-3 Euler angle rates dphi/dt (precession rate of long axis about fixed angular momentum with cone angle theta) and dpsi/dt (roll rate around long axis) have comparable magnitudes until very close to theta=pi/2, so that otherwise the true rotation period is not simply twice the primary light curve period. Furthermore dtheta/dt, nonzero due to friction, becomes asymptotically smaller as theta=pi/2 is approached, so that theta can linger within several degrees of flat spin for a relatively long time. Such a condition is likely common, and cannot be distinguished from the wobble of a cylinder with a skewed inertia tensor unless the RB has non-axisymmetric reflectivity characteristics. For an RB of known dimensions, a given value of theta fixes the relative values of dpsi/dt and dphi/dt. In forced precession, the angular momentum precesses about a symmetry axis defined by the relevant torque. However, in LEO, only gravity gradient and magnetic eddy current torques are dominant, and these

  9. Using Jet Observations to Constrain Enceladus' Rotation State

    NASA Technical Reports Server (NTRS)

    Hurford, Terry A.; Porco, C. C.

    2011-01-01

    Observations of Enceladus have revealed active jets of material erupting from cracks on its surface. It has been proposed that diurnal tidal stress may open these cracks daily when they experience tensile stresses across them, allowing eruptions to occur. An analysis of the tidal stress on jet source regions, as identified by the triangulation of jet observations, finds that there is a correlation between observations and tensile stress on the cracks. However, not all regions are predicted to be in tension when jets were observed to be active. Enceladus' rotation state, such as a physical libration or obliquity, will affect the diurnal stresses on these cracks, changing when in its orbit they experience tension and compression. We will use observations of jet activity from 2005-2007 to place constraints on rotation states of Enceladus.

  10. Strongly Correlated States of Ultracold Rotating Dipolar Fermi Gases

    SciTech Connect

    Osterloh, Klaus; Barberan, Nuria; Lewenstein, Maciej

    2007-10-19

    We study strongly correlated ground and excited states of rotating quasi-2D Fermi gases constituted of a small number of dipole-dipole interacting particles with dipole moments polarized perpendicular to the plane of motion. As the number of atoms grows, the system enters an intermediate regime, where ground states are subject to a competition between distinct bulk-edge configurations. This effect obscures their description in terms of composite fermions and leads to the appearance of novel quasihole ground states. In the presence of dipolar interactions, the principal Laughlin state at filling {nu}=1/3 exhibits a substantial energy gap for neutral (total angular momentum conserving) excitations and is well-described as an incompressible Fermi liquid. Instead, at lower fillings, the ground state structure favors crystalline order.

  11. Rotational Energy Transfer in Metastable States of Heteronuclear Molecules

    DTIC Science & Technology

    1989-01-01

    developed by Polanyi and Woodall1 1 in their studies of HF(v) relaxation and has been applied to a number of other species. Pritchard and co-workers 12 ,13...Chemiluminescence from the3 F + 12F Reaction," J. Chem. Phys. 74, 6508 (1981). 8. Clyne, Michael A.A. and McDermid, I. Stuart, "B3 H(0+ ) States of IF, ICI, and...State of ICI," 1984. 11. Polanyi , J.E. and Woodall, K.B., "Mechanisms of Rotational Relaxation," J. Chem. Phys. 56, 1563 (1972). 12. Pritchard, D.E

  12. The Astrophysical Weeds: Rotational Transitions in Excited Vibrational States

    NASA Astrophysics Data System (ADS)

    Alonso, José L.; Kolesniková, Lucie; Alonso, Elena R.; Mata, Santiago

    2017-06-01

    The number of unidentified lines in the millimeter and submillimeter wave surveys of the interstellar medium has grown rapidly. The major contributions are due to rotational transitions in excited vibrational states of a relatively few molecules that are called the astrophysical weeds. necessary data to deal with spectral lines from astrophysical weeds species can be obtained from detailed laboratory rotational measurements in the microwave and millimeter wave region. A general procedure is being used at Valladolid combining different time and/or frequency domain spectroscopic tools of varying importance for providing the precise set of spectroscopic constants that could be used to search for this species in the ISM. This is illustrated in the present contribution through its application to several significant examples. Fortman, S. M., Medvedev, I. R., Neese, C.F., & De Lucia, F.C. 2010, ApJ,725, 1682 Rotational Spectra in 29 Vibrationally Excited States of Interstellar Aminoacetonitrile, L. Kolesniková, E. R. Alonso, S. Mata, and J. L. Alonso, The Astrophysical Journal Supplement Series 2017, (in press).

  13. The Rotation State of Comet 103P/Hartley 2

    NASA Astrophysics Data System (ADS)

    Farnham, Tony; Knight, Matthew M.; Schleicher, David G.

    2016-10-01

    On November 4, 2010, the Deep Impact (DI) spacecraft made its closest approach to comet 103P/Hartley 2, passing only 694 km from the nucleus. Observations of the coma produced a lightcurve that shows the nucleus is in a state of non-principal axis rotation that evolves with time, while other observations revealed a nucleus that has concentrated collimated jets driven by CO2 emission (A'Hearn et al., 2011), large variability in the production of H2O and CO2 (Besse et al. 2016), and ice patches on the surface (Sunshine et al. 2011). To properly interpret the significance of these phenomena, it is necessary to understand the rotation of the nucleus, so that its thermal history can be derived and properly modeled, while at the same time, it is likely that the comet's high activity levels play an important role in the nucleus dynamics.An analysis of the lightcurve by Belton et al (2013) described the comet's rotation state, with two periodicities (primary of 18 h, secondary of 28 or 55 h) that change with time. Although their solution describes the periodicities observed around closest approach, it is insufficient to reproduce the changes in coma morphology with time. We are performing an analysis of the structures in the coma (Farnham 2009), using Monte Carlo routines to model the outflowing dust produced by active sources on the nucleus, to derive a comprehensive solution for the nucleus' rotation.We are also obtaining new observations of Hartley 2 in June/July 2016 (r~3.2 AU) to measure the nucleus' primary component period before the comet becomes highly active. This will provide an end-state measure of the rotation from the 2010 apparition, as well as a starting value for the current apparition, to allow its continuing evolution to be monitored. We will present an update on the status and preliminary results of these analyses.This work is funded by NASA Grant NNX12AQ64G.A'Hearn, M.F., et al. (2011) Science 332, 1396-1400Belton M.J.S., et al. (2013) Icarus 222, 595

  14. Probable Rotation States of Rocket Bodies in Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Ojakangas, Gregory W.; Anz-Meador, P.; Cowardin, H.

    2012-01-01

    In order for Active Debris Removal to be accomplished, it is critically important to understand the probable rotation states of orbiting, spent rocket bodies. As compared to the question of characterizing small unresolved debris, in this problem there are several advantages: (1) objects are of known size, mass, shape and color, (2) they have typically been in orbit for a known period of time, (3) they are large enough that resolved images may be obtainable for verification of predicted orientation, and (4) the dynamical problem is simplified to first order by largely cylindrical symmetry. It is also nearly certain for realistic rocket bodies that internal friction is appreciable in the case where residual liquid or, to a lesser degree, unconsolidated solid fuels exist. Equations of motion have been developed for this problem in which internal friction as well as torques due to solar radiation, magnetic induction, and gravitational gradient are included. In the case of pure cylindrical symmetry, the results are compared to analytical predictions patterned after the standard approach for analysis of symmetrical tops. This is possible because solar radiation and gravitational torques may be treated as conservative. Agreement between results of both methods ensures their mutual validity. For monotone symmetric cylinders, solar radiation torque vanishes if the center of mass resides at the geometric center of the object. Results indicate that in the absence of solar radiation effects, rotation states tend toward an equilibrium configuration in which rotation is about the axis of maximum inertia, with the axis of minimum inertia directed toward the center of the earth. Solar radiation torque introduces a modification to this orientation. The equilibrium state is asymptotically approached within a characteristic timescale given by a simple ratio of relevant characterizing parameters for the body in question. Light curves are simulated for the expected asymptotic final

  15. Stability of splay states in globally coupled rotators.

    PubMed

    Calamai, Massimo; Politi, Antonio; Torcini, Alessandro

    2009-09-01

    The stability of dynamical states characterized by a uniform firing rate (splay states) is analyzed in a network of N globally pulse-coupled rotators (neurons) subject to a generic velocity field. In particular, we analyze short-wavelength modes that were known to be marginally stable in the infinite N limit and show that the corresponding Floquet exponent scale as 1/N2. Moreover, we find that the sign, and thereby the stability, of this spectral component is determined by the sign of the average derivative of the velocity field. For leaky-integrate-and-fire neurons, an analytic expression for the whole spectrum is obtained. In the intermediate case of continuous velocity fields, the Floquet exponents scale faster than 1/N2 (namely, as 1/N4) and we even find strictly neutral directions in a wider class than the sinusoidal velocity fields considered by Watanabe and Strogatz [Physica D 74, 197 (1994)].

  16. Lowest eigenvalues of random Hamiltonians

    SciTech Connect

    Shen, J. J.; Zhao, Y. M.; Arima, A.; Yoshinaga, N.

    2008-05-15

    In this article we study the lowest eigenvalues of random Hamiltonians for both fermion and boson systems. We show that an empirical formula of evaluating the lowest eigenvalues of random Hamiltonians in terms of energy centroids and widths of eigenvalues is applicable to many different systems. We improve the accuracy of the formula by considering the third central moment. We show that these formulas are applicable not only to the evaluation of the lowest energy but also to the evaluation of excited energies of systems under random two-body interactions.

  17. High-resolution infrared spectroscopy of the asymmetric NO stretch band of jet-cooled nitromethane and assignment of the lowest four torsional states

    DOE PAGES

    Dawadi, Mahesh B.; Degliumberto, Lou; Perry, David S.; ...

    2017-08-10

    We used a high-throughput CW slit-jet apparatus coupled to a high-resolution FTIR to record the asymmetric NO stretch band of nitromethane. The b-type band, including torsionally excited states with m ≤ 3, has been assigned for Ka" ≤ 10, J" ≤ 20. The ground state combination differences derived from these assigned levels were fit with the RAM36 program to give an RMS deviation of 0.0006 cm-1. The band origin is 1583.0 (±0.1) cm-1 and the torsional level spacing is nearly identical to that in the ground state. The upper state levels are split into multiplets by perturbations. We also fitmore » a subset of the available upper state combination differences for m = 0, Ka' ≤ 7, J' ≤ 10 with the same program, but with rather poorer precision (0.01 cm-1) than for the ground state.« less

  18. The electronic spectrum of AgBr 2: Ab initio benchmark vs. DFT calculations on the lowest ligand-field states including spin-orbit effects

    NASA Astrophysics Data System (ADS)

    Santoyo-Castillo, I.; Ramírez-Solís, A.

    2010-10-01

    The X 2Π g, 2Σ g+ and 2Δ g states of AgBr 2 have been studied through benchmark ab initio CASSCF + Averaged Coupled Pair Functional (ACPF) and DFT calculations using especially developed valence basis sets to study the transition energies, geometries, vibrational frequencies, Mulliken charges and spin densities. The spin-orbit (SO) effects were included through the effective hamiltonian formalism using the |ΛSΣ> ACPF energies as diagonal elements. At the ACPF level, the ground state is 2Π g, in contradiction with ligand-field theory and Hartree-Fock results. The ACPF adiabatic excitation energies of the 2Σ g+ and 2Δ g states are 3825 and 20 152 cm -1, respectively. The inclusion of the SO effects leads to a pure Ω = 3/2 ( 2Π g) ground state, a Ω = 1/2 (97% 2Π g + 3% 2Σ g+) A state, a Ω = 1/2 (3% 2Π g + 97% 2Σ g+) B state, a Ω = 5/2 ( 2Δ g) C state and a Ω = 3/2 (99% 2Δ g) D state. The B97, B3LYP and PBE0 functionals, which were shown to yield accurate transition energies for CuCl 2, overestimate the X 2Π g- 2Σ g+ T e by around 25% but provide a qualitative energetic ordering in agreement with CASSCF and ACPF results. The nature of the bonding in the X 2Π g ground state is different from that of AgCl 2 since the Mulliken charge on the metal is 0.95 while the spin density is only 0.39. DFT strongly delocalizes the spin density providing even smaller values of around 0.13 on Ag not only for the ground state, but also for the 2Σ g+ state.

  19. Electronic structure of C-Li, Si-H, and Si-Li in the lowest /sup 4/. sigma. /sup -/ and /sup 2/PI states

    SciTech Connect

    Mavridis, A.; Harrison, J.F.

    1982-05-27

    We have studied the electronic structure of C-Li, Si-Li, and Si-H in the /sup 4/..sigma../sup -/ and /sup 2/pI states using ab initio SCF, MCSCF, and CI techniques. We find that, while Si-H is similar to C-H, having a /sup 2/PI ground state with the /sup 4/..sigma../sup -/ approximately 36 kcal mol/sup -1/ higher, both C-Li and Si-Li have /sup 4/..sigma../sup -/ ground states with the /sup 2/II being 33 and 14 kcal mol/sup -1/ higher, respectively. Potential energy curves and spectroscopic constants are presented for the three title molecules, and some speculation as to the possible consequences of the /sup 4/..sigma../sup -/ ground state of Si-Li and C-Li is indulged in.

  20. Refurbishment of the Oregon State University rotating rack

    SciTech Connect

    Higginbotham, J.F. )

    1991-01-01

    TRIGA reactors have experienced operational difficulties with the rotating racks used for sample irradiation. The most common problem occurs when the rack seizes, and the corrective action taken is replacement of the rack assembly. This paper describes the symptoms leading to rack failure and a refurbishment procedure to correct the problem without replacing the rack at the Oregon State University TRIGA Reactor (OSTR) Facility. This procedure was accomplished with extraordinary results from an operational and a radiation protection standpoint. The refurbishment has extended the useful life of this reactor facility with minimal financial impact. Given the declining number of university-based research reactors, it is in the nation's best interest to maintain the currently operating research reactor facilities, and the described procedure can aid in achieving that goal.

  1. Rotations

    Treesearch

    John R. Jones; Wayne D. Shepperd

    1985-01-01

    The rotation, in forestry, is the planned number of years between formation of a crop or stand and its final harvest at a specified stage of maturity (Ford-Robertson 1971). The rotation used for many species is the age of culmination of mean usable volume growth [net mean annual increment (MAI)]. At that age, usable volume divided by age reaches its highest level. That...

  2. Formation of ultracold {sup 7}Li{sup 85}Rb molecules in the lowest triplet electronic state by photoassociation and their detection by ionization spectroscopy

    SciTech Connect

    Altaf, Adeel Dutta, Sourav; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P.; Elliott, D. S.

    2015-03-21

    We report the formation of ultracold {sup 7}Li{sup 85}Rb molecules in the a{sup 3}Σ{sup +} electronic state by photoassociation (PA) and their detection via resonantly enhanced multiphoton ionization (REMPI). With our dual-species Li and Rb magneto-optical trap apparatus, we detect PA resonances with binding energies up to ∼62 cm{sup −1} below the {sup 7}Li 2s {sup 2}S{sub 1/2} + {sup 85}Rb 5p {sup 2}P{sub 1/2} asymptote. In addition, we use REMPI spectroscopy to probe the a{sup 3}Σ{sup +} state and excited electronic 3{sup 3}Π and 4{sup 3}Σ{sup +} states and identify a{sup 3}Σ{sup +} (v″ = 7–13), 3{sup 3}Π (v{sub Π}′ = 0–10), and 4{sup 3}Σ{sup +} (v{sub Σ}′ = 0–5) vibrational levels. Our line assignments agree well with ab initio calculations. These preliminary spectroscopic studies on previously unobserved electronic states are crucial to discovering transition pathways for transferring ultracold LiRb molecules created via PA to deeply bound rovibrational levels of the electronic ground state.

  3. The transition from the open minimum to the ring minimum on the ground state and on the lowest excited state of like symmetry in ozone: A configuration interaction study.

    PubMed

    Theis, Daniel; Ivanic, Joseph; Windus, Theresa L; Ruedenberg, Klaus

    2016-03-14

    The metastable ring structure of the ozone 1(1)A1 ground state, which theoretical calculations have shown to exist, has so far eluded experimental detection. An accurate prediction for the energy difference between this isomer and the lower open structure is therefore of interest, as is a prediction for the isomerization barrier between them, which results from interactions between the lowest two (1)A1 states. In the present work, valence correlated energies of the 1(1)A1 state and the 2(1)A1 state were calculated at the 1(1)A1 open minimum, the 1(1)A1 ring minimum, the transition state between these two minima, the minimum of the 2(1)A1 state, and the conical intersection between the two states. The geometries were determined at the full-valence multi-configuration self-consistent-field level. Configuration interaction (CI) expansions up to quadruple excitations were calculated with triple-zeta atomic basis sets. The CI expansions based on eight different reference configuration spaces were explored. To obtain some of the quadruple excitation energies, the method of Correlation Energy Extrapolation by Intrinsic Scaling was generalized to the simultaneous extrapolation for two states. This extrapolation method was shown to be very accurate. On the other hand, none of the CI expansions were found to have converged to millihartree (mh) accuracy at the quadruple excitation level. The data suggest that convergence to mh accuracy is probably attained at the sextuple excitation level. On the 1(1)A1 state, the present calculations yield the estimates of (ring minimum-open minimum) ∼45-50 mh and (transition state-open minimum) ∼85-90 mh. For the (2(1)A1-(1)A1) excitation energy, the estimate of ∼130-170 mh is found at the open minimum and 270-310 mh at the ring minimum. At the transition state, the difference (2(1)A1-(1)A1) is found to be between 1 and 10 mh. The geometry of the transition state on the 1(1)A1 surface and that of the minimum on the 2(1)A1 surface

  4. The transition from the open minimum to the ring minimum on the ground state and on the lowest excited state of like symmetry in ozone: A configuration interaction study

    DOE PAGES

    Theis, Daniel; Ivanic, Joseph; Windus, Theresa L.; ...

    2016-03-10

    The metastable ring structure of the ozone 11A1 ground state, which theoretical calculations have shown to exist, has so far eluded experimental detection. An accurate prediction for the energy difference between this isomer and the lower open structure is therefore of interest, as is a prediction for the isomerization barrier between them, which results from interactions between the lowest two 1A1 states. In the present work, valence correlated energies of the 11A1 state and the 21A1 state were calculated at the 11A1 open minimum, the 11A1 ring minimum, the transition state between these two minima, the minimum of the 21A1more » state, and the conical intersection between the two states. The geometries were determined at the full-valence multi-configuration self-consistent-field level. Configuration interaction (CI) expansions up to quadruple excitations were calculated with triple-zeta atomic basis sets. The CI expansions based on eight different reference configuration spaces were explored. To obtain some of the quadruple excitation energies, the method of CorrelationEnergy Extrapolation by Intrinsic Scaling was generalized to the simultaneous extrapolation for two states. This extrapolation method was shown to be very accurate. On the other hand, none of the CI expansions were found to have converged to millihartree (mh) accuracy at the quadruple excitation level. The data suggest that convergence to mh accuracy is probably attained at the sextuple excitation level. On the 11A1 state, the present calculations yield the estimates of (ring minimum—open minimum) ~45–50 mh and (transition state—open minimum) ~85–90 mh. For the (21A1–1A1) excitation energy, the estimate of ~130–170 mh is found at the open minimum and 270–310 mh at the ring minimum. At the transition state, the difference (21A1–1A1) is found to be between 1 and 10 mh. The geometry of the transition state on the 11A1 surface and that of the minimum on the 21A1 surface nearly coincide

  5. Rotational state-dependent attachment of He atoms to cold molecular ions: An action spectroscopic scheme for rotational spectroscopy

    NASA Astrophysics Data System (ADS)

    Brünken, Sandra; Kluge, Lars; Stoffels, Alexander; Pérez-Ríos, Jesús; Schlemmer, Stephan

    2017-02-01

    We present a kinetics model description of a newly developed action spectroscopic method for rotational spectroscopy based on rotational state-dependent three-body attachment of He atoms to cold molecular ions stored in a cryogenic 22-pole ion trap. The model results from numerical simulations and an approximate analytical expression are compared to measurements of the J = 1- 0 rotational transition of CD+, for which we obtain a refined transition frequency of 453.5218509(7) GHz. From the analysis of the spectroscopic data recorded at varying experimental conditions, e.g. over a wide range of He number densities and excitation powers, we deduce that the ternary rate coefficient in the first excited rotational state of CD+ is reduced to (55 ± 5) % of the rotational ground state value. This decrease in the rate coefficient can be rationalized as an increase of the redissociation probability in the ternary collision process. A summary of rotational spectroscopy measurements of other molecular ions using the new method will be given, and its general applicability is discussed.

  6. Reversal of Hückel (anti)aromaticity in the lowest triplet states of hexaphyrins and spectroscopic evidence for Baird's rule

    NASA Astrophysics Data System (ADS)

    Sung, Young Mo; Yoon, Min-Chul; Lim, Jong Min; Rath, Harapriya; Naoda, Koji; Osuka, Atsuhiro; Kim, Dongho

    2015-05-01

    The reversal of (anti)aromaticity in a molecule's triplet excited state compared with its closed-shell singlet ground state is known as Baird's rule and has attracted the interest of synthetic, physical organic chemists and theorists because of the potential to modulate the fundamental properties of highly conjugated molecules. Here we show that two closely related bis-rhodium hexaphyrins (R26H and R28H) containing [26] and [28] π-electron peripheries, respectively, exhibit properties consistent with Baird's rule. In the ground state, R26H exhibits a sharp Soret-like band and distinct Q-like bands characteristic of an aromatic porphyrinoid, whereas R28H exhibits a broad absorption spectrum without Q-like bands, which is typical of an antiaromatic porphyrinoid. In contrast, the T-T absorption of R26H is broad, weak and featureless, whereas that of R28H displays an intense and sharp Soret-like band. These spectral signatures, in combination with quantum chemical calculations, are in line with qualitative expectations based on Baird's rule.

  7. Density functional theory calculations of the lowest energy quintet and triplet states of model hemes: role of functional, basis set, and zero-point energy corrections.

    PubMed

    Khvostichenko, Daria; Choi, Andrew; Boulatov, Roman

    2008-04-24

    We investigated the effect of several computational variables, including the choice of the basis set, application of symmetry constraints, and zero-point energy (ZPE) corrections, on the structural parameters and predicted ground electronic state of model 5-coordinate hemes (iron(II) porphines axially coordinated by a single imidazole or 2-methylimidazole). We studied the performance of B3LYP and B3PW91 with eight Pople-style basis sets (up to 6-311+G*) and B97-1, OLYP, and TPSS functionals with 6-31G and 6-31G* basis sets. Only hybrid functionals B3LYP, B3PW91, and B97-1 reproduced the quintet ground state of the model hemes. With a given functional, the choice of the basis set caused up to 2.7 kcal/mol variation of the quintet-triplet electronic energy gap (DeltaEel), in several cases, resulting in the inversion of the sign of DeltaEel. Single-point energy calculations with triple-zeta basis sets of the Pople (up to 6-311G++(2d,2p)), Ahlrichs (TZVP and TZVPP), and Dunning (cc-pVTZ) families showed the same trend. The zero-point energy of the quintet state was approximately 1 kcal/mol lower than that of the triplet, and accounting for ZPE corrections was crucial for establishing the ground state if the electronic energy of the triplet state was approximately 1 kcal/mol less than that of the quintet. Within a given model chemistry, effects of symmetry constraints and of a "tense" structure of the iron porphine fragment coordinated to 2-methylimidazole on DeltaEel were limited to 0.3 kcal/mol. For both model hemes the best agreement with crystallographic structural data was achieved with small 6-31G and 6-31G* basis sets. Deviation of the computed frequency of the Fe-Im stretching mode from the experimental value with the basis set decreased in the order: nonaugmented basis sets, basis sets with polarization functions, and basis sets with polarization and diffuse functions. Contraction of Pople-style basis sets (double-zeta or triple-zeta) affected the results

  8. The spectroscopy of AgF: CASSCF+CASPT2 calculations on the lowest 3Σ+, 1Σ+, 3Π, 1Π, 3Δ, and 1Δ excited states

    NASA Astrophysics Data System (ADS)

    Ramírez-Solís, A.; Daudey, J. P.

    2000-11-01

    The spectroscopic properties of the three lowest-lying (X,2 and 3)1Σ+, the first 3Σ+, the two lowest-lying (1 and 2)3Π, the first 1Π, and the 3,1Δ states of the AgF molecule have been studied through extensive CASSCF (complete active space self-consistent field)+CASPT2 (complete active space second-order perturbational) calculations, using a 19-active-electron relativistic effective core potential for Ag and large Gaussian basis sets for both atoms. Strong mixtures of the Ag+(4d95s1)F-(2s22p6) ionic and Ag(4d95s2)F(2s22p5) or Ag(4d105s1)F(2s22p5) neutral configurations were found for the 3Σ+, 2 1Σ+, and 1 3Π states between 4.0 and 4.4 a.u., while for the higher lying states no evident neutral-ionic crossings were found. This leads to curves that present local maxima at 4.3 a.u. for the 2 1Σ+ and 3Σ+ states as well as for the 1 3Π state at 4.0 a.u. The 2 3Π excited state shows the lowest ionic character of all the states. The calculated spectroscopic constants for all the studied states are reported and found in good accordance with available experimental data. The question of the nature of the electronic parent state of the observed B0+ state, responsible for the most intense transition and which is the shortest lived excited state of AgF, is thoroughly addressed in the light of the present results. They clearly indicate that the B0+ state is not correlated with the Rydberg Ag+(4d95p1)+F-(2s22p6) ionic structure, as previously proposed [J. Chem. Phys. 102, 4482 (1995)]. Since the 2 1Σ+ state has been shown to be the ΛSΣ electronic parent state of the fine-structure A0+ state (these results confirm this idea), and given the difference between the calculated Te (1513 cm-1) of the 2 1Σ+ and 1 3Π states, these calculations point to this latter state as the ΛSΣ parent of the experimental B0+ state. At this level of calculation, the next higher lying state that could contribute (3 1Σ+) through spin-orbit couplings to this B0+ state lies more than 8000

  9. Dimension of discrete variable representation for mixed quantum/classical computation of three lowest vibrational states of OH stretching in liquid water

    NASA Astrophysics Data System (ADS)

    Jeon, Kiyoung; Yang, Mino

    2017-02-01

    Three low-lying vibrational states of molecular systems are responsible for the signals of linear and third-order nonlinear vibrational spectroscopies. Theoretical studies based on mixed quantum/classical calculations provide a powerful way to analyze those experiments. A statistically meaningful result can be obtained from the calculations by solving the vibrational Schrödinger equation over many numbers of molecular configurations. The discrete variable representation (DVR) method is a useful technique to calculate vibrational eigenstates subject to an arbitrary anharmonic potential surface. Considering the large number of molecular configurations over which the DVR calculations are repeated, the calculations are desired to be optimized in balance between the cost and accuracy. We determine a dimension of the DVR method which appears to be optimum for the calculations of the three states of molecular vibrations with anharmonic strengths often found in realistic molecular systems. We apply the numerical technique to calculate the local OH stretching frequencies of liquid water, which are well known to be widely distributed due to the inhomogeneity in molecular configuration, and found that the frequencies of the 0-1 and 1-2 transitions are highly correlated. An empirical relation between the two frequencies is suggested and compared with the experimental data of nonlinear IR spectroscopies.

  10. Identification of the Lowest T =2 , Jπ=0+ Isobaric Analog State in 52Co and Its Impact on the Understanding of β -Decay Properties of 52Ni

    NASA Astrophysics Data System (ADS)

    Xu, X.; Zhang, P.; Shuai, P.; Chen, R. J.; Yan, X. L.; Zhang, Y. H.; Wang, M.; Litvinov, Yu. A.; Xu, H. S.; Bao, T.; Chen, X. C.; Chen, H.; Fu, C. Y.; Kubono, S.; Lam, Y. H.; Liu, D. W.; Mao, R. S.; Ma, X. W.; Sun, M. Z.; Tu, X. L.; Xing, Y. M.; Yang, J. C.; Yuan, Y. J.; Zeng, Q.; Zhou, X.; Zhou, X. H.; Zhan, W. L.; Litvinov, S.; Blaum, K.; Audi, G.; Uesaka, T.; Yamaguchi, Y.; Yamaguchi, T.; Ozawa, A.; Sun, B. H.; Sun, Y.; Dai, A. C.; Xu, F. R.

    2016-10-01

    Masses of 52g,52mCo were measured for the first time with an accuracy of ˜10 keV , an unprecedented precision reached for short-lived nuclei in the isochronous mass spectrometry. Combining our results with the previous β -γ measurements of 52Ni, the T =2 , Jπ=0+ isobaric analog state (IAS) in 52Co was newly assigned, questioning the conventional identification of IASs from the β -delayed proton emissions. Using our energy of the IAS in 52Co, the masses of the T =2 multiplet fit well into the isobaric multiplet mass equation. We find that the IAS in 52Co decays predominantly via γ transitions while the proton emission is negligibly small. According to our large-scale shell model calculations, this phenomenon has been interpreted to be due to very low isospin mixing in the IAS.

  11. Coherent control of molecular rotational state populations by periodic phase-step modulation

    SciTech Connect

    Zhang Shian; Wu Meizhen; Lu Chenhui; Jia Tianqing; Sun Zhenrong

    2011-10-15

    We theoretically demonstrate that the molecular rotational state populations through an impulsive nonresonant Raman process can be manipulated by shaping the femtosecond laser pulse with a periodic phase-step modulation. We show that, by precisely controlling these parameters characterizing the periodic phase-step modulation, both the odd and even rotational state populations can be completely suppressed or reconstructed as that induced by the transform-limited laser pulse, and the relative excitation between the odd and even rotational state populations can also be obtained. Furthermore, we show that the field-free molecular alignment can be manipulated due to the modulation of the odd and even rotational state populations.

  12. The transition from the open minimum to the ring minimum on the ground state and on the lowest excited state of like symmetry in ozone: A configuration interaction study

    SciTech Connect

    Theis, Daniel; Ivanic, Joseph; Windus, Theresa L.; Ruedenberg, Klaus

    2016-03-10

    The metastable ring structure of the ozone 11A1 ground state, which theoretical calculations have shown to exist, has so far eluded experimental detection. An accurate prediction for the energy difference between this isomer and the lower open structure is therefore of interest, as is a prediction for the isomerization barrier between them, which results from interactions between the lowest two 1A1 states. In the present work, valence correlated energies of the 11A1 state and the 21A1 state were calculated at the 11A1 open minimum, the 11A1 ring minimum, the transition state between these two minima, the minimum of the 21A1 state, and the conical intersection between the two states. The geometries were determined at the full-valence multi-configuration self-consistent-field level. Configuration interaction (CI) expansions up to quadruple excitations were calculated with triple-zeta atomic basis sets. The CI expansions based on eight different reference configuration spaces were explored. To obtain some of the quadruple excitation energies, the method of CorrelationEnergy Extrapolation by Intrinsic Scaling was generalized to the simultaneous extrapolation for two states. This extrapolation method was shown to be very accurate. On the other hand, none of the CI expansions were found to have converged to millihartree (mh) accuracy at the quadruple excitation level. The data suggest that convergence to mh accuracy is probably attained at the sextuple excitation level. On the 11A1 state, the present calculations yield the estimates of (ring minimum—open minimum) ~45–50 mh and (transition state—open minimum) ~85–90 mh. For the (21A11A1) excitation energy, the estimate of ~130–170 mh is found at the open minimum and 270–310 mh at the ring minimum. At the

  13. Rotationally inelastic scattering in CH4+He, Ne, and Ar: State-to-state cross sections via direct infrared laser absorption in crossed supersonic jets

    NASA Astrophysics Data System (ADS)

    Chapman, William B.; Schiffman, Aram; Hutson, Jeremy M.; Nesbitt, David J.

    1996-09-01

    Absolute integral state-to-state cross sections are reported for rotationally inelastic scattering in crossed jets of CH4 with the rare gases He, Ne, Ar, at center of mass collision energies of 460±90, 350±70, and 300±60 cm-1, respectively. CH4 seeded in Ar buffer gas is cooled in a pulsed supersonic expansion into the three lowest rotational levels allowed by nuclear spin statistics corresponding to A(J=0), F(J=1), and E(J=2) symmetry. Rotational excitation occurs in single collisions with rare gas atoms from a second pulsed supersonic jet. The column integrated densities of CH4 in both initial and final scattering states are subsequently probed in the jet intersection region via direct absorption of light from a narrow bandwidth (0.0001 cm-1), single mode color center laser. Total inelastic cross sections for collisional loss out of the J=0, 1, and 2 methane states are determined in absolute units from the linear decrease of infrared absorption signals as a function of collider gas concentration. Tuning of the ir laser source also permits probing of the collisionally excited rotational states with quantum state and velocity resolution; column integrated scattering densities are measured for all energetically accessible final states and used to infer absolute inelastic cross sections for state-to-state energy transfer. The observed trends are in good qualitative agreement with quantum state resolved pressure broadening studies; however, the dependences of the rotationally inelastic cross sections on nuclear spin modification (i.e., J) and rotational inelasticity (i.e., ΔJ) is not well predicted by conventional angular momentum or energy gap models. More rigorous comparison with the quantum state-resolved scattering data is obtained from full close coupled scattering calculations on trial potential energy surfaces by Buck and co-workers [Chem. Phys. Lett. 98, 199 (1983); Mol. Phys. 55, 1233, 1255 (1985)] for each of the three CH4+rare gas systems. Agreement

  14. Rotationally resolved state-to-state photoelectron study of niobium carbide radical

    SciTech Connect

    Luo, Zhihong; Huang, Huang; Zhang, Zheng; Chang, Yih-Chung; Ng, C. Y.

    2014-07-14

    By employing the two-color visible (VIS)-ultraviolet (UV) laser photoexcitation scheme and the pulsed field ionization-photoelectron (PFI-PE) detection, we have obtained rovibronically selected and resolved photoelectron spectra for niobium carbide cation (NbC{sup +}). The fully rotationally resolved state-to-state VIS-UV-PFI-PE spectra thus obtained allow the unambiguous assignments of rotational photoionization transitions, indicating that the electronic configuration and term symmetry of NbC{sup +}(X{sup ~}) ground state are …10σ{sup 2} 5π{sup 4} 11σ{sup 2} (X{sup ~1}Σ{sup +}). Furthermore, the rotational analysis of these spectra yields the ionization energy of NbC [IE(NbC)] to be 56 369.2 ± 0.8 cm{sup −1} (6.9889 ± 0.0001 eV) and the rotation constant B{sub 0}{sup +} = 0.5681 ± 0.0007 cm{sup −1}. The latter value allows the determination of the bond distance r{sub 0}{sup +} = 1.671 ± 0.001 Å for NbC{sup +}(X{sup ~1}Σ{sup +}). Based on conservation of energy, the IE(NbC) determined in the present study along with the known IE(Nb) gives the difference of 0 K bond dissociation energies (D{sub 0}’s) for NbC{sup +} and NbC, D{sub 0}(NbC{sup +}) − D{sub 0}(NbC) = −1855.4 ± 0.9 cm{sup −1} (−0.2300 ± 0.0001 eV). The energetic values and the B{sub 0}{sup +} constant determined in this work are valuable for benchmarking state-of-the-art ab initio quantum calculations of 4d transition metal-containing molecules.

  15. Vortex distribution in the lowest Landau level

    SciTech Connect

    Aftalion, Amandine; Blanc, Xavier; Nier, Francis

    2006-01-15

    We study the vortex distribution of the wave functions minimizing the Gross-Pitaevskii energy for a fast rotating condensate in the lowest Landau level (LLL): we prove that the minimizer cannot have a finite number of zeroes, thus the lattice is infinite, but not uniform. This uses the explicit expression of the projector onto the LLL. We also show that any slow varying envelope function can be approximated in the LLL by distorting the lattice. This is used in particular to approximate the inverted parabola and understand the role of 'invisible' vortices: the distortion of the lattice is very small in the Thomas-Fermi region but quite large outside, where the 'invisible' vortices lie.

  16. Evidence of enhanced radius of Hoyle rotational state in12C inelastic scattering

    NASA Astrophysics Data System (ADS)

    Ito, M.

    2017-06-01

    Nuclear radius of three α rotational state in12C with a life time of 10-21 second, which has been expected to have much more extended radius than the ground12C nucleus, is speculated from systematic analysis of the differential cross section of the α +12C inelastic scattering. Present analysis predicts about 0.6 ∼ 1.0 fm enhancement in the matter radius of the three α rotational state in comparison to the normal radius of the ground state. The spatial extension of the three α rotational state is comparable to the extended radius observed in the neutron halo phenomena.

  17. Using custom potentials to access quantum Hall states in rotating Bose gases

    NASA Astrophysics Data System (ADS)

    Morris, Alexis G.; Feder, David L.

    2007-03-01

    The exact ground states of zero-temperature rotating Bose gases confined in quasi-two-dimensional harmonic traps are studied numerically, for small numbers of alkali atoms. As the rotation frequency increases, the interacting Bose gas undergoes a series of transitions from one quantum Hall state to another. We have investigated the possibility of facilitating access to specific quantum Hall states through the addition of customized potentials to the existing trapping potential. For the right choice of potential, we show that creation of predetermined quantum Hall states in rotating Bose gases should be possible using current experimental setups. (Research supported by NSERC, iCORE and CFI)

  18. Mercury's rotational state from combined MESSENGER laser altimeter and image data

    NASA Astrophysics Data System (ADS)

    Stark, Alexander; Oberst, Jürgen; Preusker, Frank; Margot, Jean-Luc; Phillips, Roger J.; Neumann, Gregory A.; Smith, David E.; Zuber, Maria T.; Solomon, Sean C.

    2016-04-01

    With orbital data from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, we measured the rotational state of Mercury. We developed a novel approach that combined digital terrain models from stereo images (stereo DTMs) and laser altimeter data, and we applied it to 3 years of MESSENGER observations. We find a large libration amplitude, which in combination with the measured obliquity confirms that Mercury possesses a liquid outer core. Our results confirm previous Earth-based observations of Mercury's rotational state. However, we measured a rotation rate that deviates significantly from the mean resonant rotation rate. The larger rotation rate can be interpreted as the signature of a long-period libration cycle. From these findings we derived new constraints on the interior structure of Mercury. The measured rotational parameters define Mercury's body-fixed frame and are critical for the coordinate system of the planet as well as for planning the future BepiColombo spacecraft mission.

  19. Rotational spectra of the X 2Sigma(+) states of CaH and CaD

    NASA Technical Reports Server (NTRS)

    Frum, C. I.; Oh, J. J.; Cohen, E. A.; Pickett, H. M.

    1993-01-01

    The rotational spectra of the 2Sigma(2+) ground states of calcium monohydride and monodeuteride have been recorded in absorption between 250 and 700 GHz. The gas phase free radicals have been produced in a ceramic furnace by the reaction of elemental calcium with molecular hydrogen or deuterium in the presence of an electrical discharge. The molecular constants including the rotational constant, centrifugal distortion constants, spin-rotation constants, and magnetic hyperfine interaction constants have been extracted from the spectra.

  20. Rotational spectra of the X 2Sigma(+) states of CaH and CaD

    NASA Technical Reports Server (NTRS)

    Frum, C. I.; Oh, J. J.; Cohen, E. A.; Pickett, H. M.

    1993-01-01

    The rotational spectra of the 2Sigma(2+) ground states of calcium monohydride and monodeuteride have been recorded in absorption between 250 and 700 GHz. The gas phase free radicals have been produced in a ceramic furnace by the reaction of elemental calcium with molecular hydrogen or deuterium in the presence of an electrical discharge. The molecular constants including the rotational constant, centrifugal distortion constants, spin-rotation constants, and magnetic hyperfine interaction constants have been extracted from the spectra.

  1. Composite Fermi liquids in the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Wang, Chong; Senthil, T.

    2016-12-01

    We study composite Fermi liquid (CFL) states in the lowest Landau level (LLL) limit at a generic filling ν =1/n . We begin with the old observation that, in compressible states, the composite fermion in the lowest Landau level should be viewed as a charge-neutral particle carrying vorticity. This leads to the absence of a Chern-Simons term in the effective theory of the CFL. We argue here that instead a Berry curvature should be enclosed by the Fermi surface of composite fermions, with the total Berry phase fixed by the filling fraction ϕB=-2 π ν . We illustrate this point with the CFL of fermions at filling fractions ν =1 /2 q and (single and two-component) bosons at ν =1 /(2 q +1 ) . The Berry phase leads to sharp consequences in the transport properties including thermal and spin Hall conductances. We emphasize that these results only rely on the LLL limit and do not require particle-hole symmetry, which is present microscopically only for fermions at ν =1 /2 . Nevertheless, we show that the existing LLL theory of the composite Fermi liquid for bosons at ν =1 does have an emergent particle-hole symmetry. We interpret this particle-hole symmetry as a transformation between the empty state at ν =0 and the boson integer quantum hall state at ν =2 . This understanding enables us to define particle-hole conjugates of various bosonic quantum Hall states which we illustrate with the bosonic Jain and Pfaffian states. For bosons at ν =1 we construct paired non-Abelian states distinct from both the standard bosonic Pfaffian and its particle hole conjugate and show how they may arise naturally out of the neutral vortex composite Fermi liquid. The bosonic particle-hole symmetry can be realized exactly on the surface of a three-dimensional boson topological insulator. We also show that with the particle-hole and spin S U (2 ) rotation symmetries, there is no gapped topological phase for bosons at ν =1 . Finally we comment on systems that are not strictly in the

  2. State-Space Modeling, System Identification and Control of a 4th Order Rotational Mechanical System

    DTIC Science & Technology

    2009-12-01

    SYSTEM IDENTIFICATION AND CONTROL OF A 4th ORDER ROTATIONAL MECHANICAL SYSTEM by Jeremiah P. Anderson December 2009 Thesis Advisor...DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE State-space Modeling, System Identification and Control of a 4th Order Rotational Mechanical...Educational Control Products is modeled from first principles and represented in state-space form. Identification of the state-space parameters was

  3. The lowest ionization potentials of Al2

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Barnes, Leslie A.; Taylor, Peter R.

    1988-01-01

    Potential curves for the lowest two electronic states (X 2 sigma g + and A 2 pi u) of Al2(+) were computed using complete active space SCF/multireference CI wave functions and large Gaussian basis sets. The lowest observable vertical ionization potential (to Al2(+) X 2 sigma g +) of the Al2 X 3 pi u ground state is calculated to occur around 6.1 eV, in excellent agreement with the experimental range of 6.0 to 6.42 eV obtained in recent cluster ionization studies by Cox and co-workers. The second vertical ionization potential (to Al2(+) A 2 pi u) occurs near 6.4 eV, also within the experimental range. The adiabatic IP of 5.90 eV is in good agreement with the value of 5.8 to 6.1 eV deduced by Hanley and co-workers from the difference in thresholds between collision induced dissociation processes of Al3(+). The computed IP values are somewhat larger than those deduced from branching ratios in cluster fragmentation experiments by Jarrold and co-workers. The observation of an ionization threshold below 6.42 eV is shown to be incompatible with an Al2 ground electronic state assignment of 3 sigma g -, but the separation between the two lowest states of Al2 is so small that it is likely that both are populated in the experiments, so that this does not provide unambiguous support for the recent theoretical assignment of the ground state as 3 pi u.

  4. Rotationally resolved state-to-state photoelectron study of zirconium monoxide cation (ZrO+)

    NASA Astrophysics Data System (ADS)

    Luo, Zhihong; Chang, Yih-Chung; Zhang, Zheng; Ng, C. Y.

    2015-08-01

    Using two-colour visible (Vis)-ultraviolet (UV) photoionisation and pulsed field ionisation-photoelectron (PFI-PE) methods, we have obtained cleanly rotationally resolved photoelectron spectra for ZrO+(X 2Δ3/2,5/2; v+ = 0, 1, and 2). The rotation assignment of these state-to-state Vis-UV-PFI-PE spectra has allowed the unambiguous determination of the ground state term symmetry for ZrO+(X) to be 2Δ3/2, and the adiabatic ionisation energy of 90Zr16O, IE(90Zr16O) = 54,948.3(8) cm-1 [6.81272(10) eV]. The symmetry of the ionic ZrO+(X 2Δ3/2) ground state determined here disagrees with that reported in previous experiments. The rotational and vibrational constants determined in this experiment for the ionic 90Zr16O+(X 2Δ3/2) ground state are: Be+ = 0.4343(8) cm-1 and αe+ = 0.0019(5) cm-1, and ωe+ = 991.2(8) cm-1 and ωe+xe+ = 3.5(8) cm-1; and those for the ionic 90Zr16O+(X 2Δ5/2) excited spin-orbit state are: Be+ = 0.4357(6) cm-1 and αe+ = 0.0022(4) cm-1, and ωe+ = 991.9(8) cm-1 and ωe+xe+ = 3.6(8) cm-1, respectively. Based on the latter Be+ value, the equilibrium bond distances are determined to be re+ = 1.691(2) Å for 90Zr16O+(X 2Δ3/2) and re+ = 1.688(1) Å for 90Zr16O+(X 2Δ5/2). The IE(ZrO) along with the spectroscopic constants obtained here are valuable for benchmarking the ab initio quantum chemical calculations for energetic and structural predictions of ZrO/ZrO+.

  5. Lifetimes of superdeformed rotational states in {sup 36}Ar.

    SciTech Connect

    Svensson, C. E.; Macchiavelli, A. O.; Juodagalvis, A.; Poves, A.; Ragnarsson, I.; Aberg, S.; Appelbe, D. E.; Austin, R. A. E.; Ball, G. C.; Carpenter, M. P.; Caurier, E.; Clark, R. M.; Cromaz, M.; Deleplanque, M. A.; Diamond, R. M.; Fallon, P.; Janssens, R. V. F.; Lane, G. J.; Lee, I. Y.; Nowacki, F.; Sarantites, D. G.; Stephens, F. S.; Vetter, K.; Ward, D.; Physics; LBNL; Lund Inst. of Tech.; Univ. Autonoma de Madrid; McMaster Univ.; TRIUMF; Univ. Louis Pasteur; Washington Univ.

    2001-06-01

    Lifetimes have been measured in a superdeformed rotational band recently identified in the N=Z nucleus {sup 36}Ar. A large low-spin quadrupole deformation ({beta}{sub 2}=0.46{+-}0.03) is confirmed and a decrease in the collectivity is observed as the high-spin band termination at I{sup {pi}}=16{sup +} is approached. Detailed comparisons of the experimental B(E2) values with the results of cranked Nilsson-Strutinsky and large-scale (s{sub 1/2}d{sub 3/2})-pf spherical shell model calculations indicate the need for a more refined treatment of transition matrix elements close to termination in the former, and the inclusion of the complete sd-pf model space in the latter description of this highly-collective rotational band.

  6. Analytic continuation of the rotating black hole state counting

    NASA Astrophysics Data System (ADS)

    Achour, Jibril Ben; Noui, Karim; Perez, Alejandro

    2016-08-01

    In loop quantum gravity, a spherical black hole can be described in terms of a Chern-Simons theory on a punctured 2-sphere. The sphere represents the horizon. The punctures are the edges of spin-networks in the bulk which cross the horizon and carry quanta of area. One can generalize this construction and model a rotating black hole by adding an extra puncture colored with the angular momentum J in the 2-sphere. We compute the entropy of rotating black holes in this model and study its semi-classical limit. After performing an analytic continuation which sends the Barbero-Immirzi parameter to γ = ± i,weshowthattheleadingorderterminthesemi-classicalexpansionoftheentropy reproduces the Bekenstein-Hawking law independently of the value of J.

  7. Equation of State Dependence of Gravitational Waves from Rapidly Rotating Core-Collapse

    NASA Astrophysics Data System (ADS)

    Richers, Sherwood; Ott, Christian D.; Abdikamalov, Ernazar

    2016-03-01

    We carry out axisymmetric simulations of rotating core-collapse, exploring over 92 precollapse rotational configurations and 18 different finite-temperature microphysical equations of state (EOS) using the general-relativistic hydrodynamical code CoCoNuT. Our focus is on gravitational wave (GW) emission. We find that the GW wave signature depends systematically on the rotation rate of the inner core at bounce and the compactness of the protoneutron star (PNS), set by the EOS and rotation. The GW signal from core bounce is almost independent of the EOS. However, the frequency of the post-bounce ring down signal from the fundamental quadrupole oscillation mode of the PNS is dependent on both rotation and the EOS, increasing with rotation rate and compactness. We will discuss the origin of the EOS-dependent f-mode frequency variation and its potential observability with Advanced LIGO.

  8. QED effects in molecules: test on rotational quantum states of H2.

    PubMed

    Salumbides, E J; Dickenson, G D; Ivanov, T I; Ubachs, W

    2011-07-22

    Quantum electrodynamic effects have been systematically tested in the progression of rotational quantum states in the X 1Σ(g)(+), v=0 vibronic ground state of molecular hydrogen. High-precision Doppler-free spectroscopy of the EF 1Σ(g)(+)-X 1Σ(g)(+) (0,0) band was performed with 0.005  cm(-1) accuracy on rotationally hot H2 (with rotational quantum states J up to 16). QED and relativistic contributions to rotational level energies as high as 0.13  cm(-1) are extracted, and are in perfect agreement with recent calculations of QED and high-order relativistic effects for the H2 ground state.

  9. The asymptotic state of rotating homogeneous turbulence at high Reynolds numbers

    NASA Technical Reports Server (NTRS)

    Squires, Kyle D.; Chasnov, Jeffrey R.; Mansour, Nagi N.; Cambon, Claude

    1994-01-01

    The long-time, asymptotic state of rotating homogeneous turbulence at high Reynolds numbers has been examined using large-eddy simulation of the incompressible Navier-Stokes equations. The simulations were carried out using 128 x 128 x 512 collocation points in a computational domain that is four times longer along the rotation axis than in the other directions. Subgrid-scale motions in the simulations were parameterized using a spectral eddy viscosity modified for system rotation. Simulation results show that in the asymptotic state the turbulence kinetic energy undergoes a power-law decay with an exponent which is independent of rotation rate, depending only on the low-wavenumber form of the initial energy spectrum. Integral lengthscale growth in the simulations is also characterized by power-law growth; the correlation length of transverse velocities exhibiting much more rapid growth than observed in non-rotating turbulence.

  10. Modelling the bacterial photosynthetic reaction center. VI. Use of density-functional theory to determine the nature of the vibronic coupling between the four lowest-energy electronic states of the special-pair radical cation

    NASA Astrophysics Data System (ADS)

    Reimers, Jeffrey R.; Shapley, Warwick A.; Rendell, Alistair P.; Hush, Noel S.

    2003-08-01

    It is now over ten years since the first FTIR spectra were recorded of the radical cation of the special-pair, a dimer of bacteriochlorophyll molecules that forms the primary electron donor responsible for primary charge separation in bacterial photosynthesis. While spectra of this type promise to reveal much concerning the role of the special pair electron donor in photosynthesis, attempts to model and interpret them have been limited by poor knowledge of the vibrationally specific aspects of the electron-phonon coupling and have thus been restricted to crude model calculations only. We develop techniques through which density-functional theory can be employed to evaluate most of the unknown properties. This includes symmetric-mode displacements, antisymmetric-mode vibronic coupling constants, and interstate electronic couplings evaluated for interactions between the four lowest-energy states of the special-pair cation radical: the ground state, the primary hole-transfer state, and states involving these two combined with SHOMO to HOMO transitions. Geometry optimizations are performed for all four states of the dimer while vibrational analyses are obtained for the first two; vibronic coupling constants are extracted from analysis of stolen infrared transition moments using Herzberg-Teller theory. Quantitatively, these results are employed in the subsequent paper in this series to simulate the observed spectra. Qualitatively, these results indicate that: (1) vibronic coupling occurs through a large number of antisymmetric modes of the dimer rather than through a small number of strongly active modes, (2) the role of symmetric vibrational motions of the dimer is only minor, (3) that the active symmetric modes are significant in number and low in frequency, (4) that vibronic coupling between the hole-transfer state and the SHOMO to HOMO state is relatively weak and influences spectra only near resonance, and (5) that the calculated electronic couplings are

  11. Investigation of the asymptotic state of rotating turbulence using large-eddy simulation

    NASA Technical Reports Server (NTRS)

    Squires, Kyle D.; Chasnov, Jeffrey R.; Mansour, Nagi N.; Cambon, Claude

    1993-01-01

    Study of turbulent flows in rotating reference frames has long been an area of considerable scientific and engineering interest. Because of its importance, the subject of turbulence in rotating reference frames has motivated over the years a large number of theoretical, experimental, and computational studies. The bulk of these previous works has served to demonstrate that the effect of system rotation on turbulence is subtle and remains exceedingly difficult to predict. A rotating flow of particular interest in many studies, including the present work, is examination of the effect of solid-body rotation on an initially isotropic turbulent flow. One of the principal reasons for the interest in this flow is that it represents the most basic turbulent flow whose structure is altered by system rotation but without the complicating effects introduced by mean strains or flow inhomogeneities. The assumption of statistical homogeneity considerably simplifies analysis and computation. The principal objective of the present study has been to examine the asymptotic state of solid-body rotation applied to an initially isotropic, high Reynolds number turbulent flow. Of particular interest has been to determine the degree of two-dimensionalization and the existence of asymptotic self-similar states in homogeneous rotating turbulence.

  12. Rotating machinery prognostics: State of the art, challenges and opportunities

    NASA Astrophysics Data System (ADS)

    Heng, Aiwina; Zhang, Sheng; Tan, Andy C. C.; Mathew, Joseph

    2009-04-01

    Machinery prognosis is the forecast of the remaining operational life, future condition, or probability of reliable operation of an equipment based on the acquired condition monitoring data. This approach to modern maintenance practice promises to reduce downtime, spares inventory, maintenance costs, and safety hazards. Given the significance of prognostics capabilities and the maturity of condition monitoring technology, there have been an increasing number of publications on rotating machinery prognostics in the past few years. These publications covered a wide spectrum of prognostics techniques. This review article first synthesises and places these individual pieces of information in context, while identifying their merits and weaknesses. It then discusses the identified challenges, and in doing so, alerts researchers to opportunities for conducting advanced research in the field. Current methods for predicting rotating machinery failures are summarised and classified as conventional reliability models, condition-based prognostics models and models integrating reliability and prognostics. Areas in need of development or improvement include the integration of condition monitoring and reliability, utilisation of incomplete trending data, consideration of effects from maintenance actions and variable operating conditions, derivation of the non-linear relationship between measured data and actual asset health, consideration of failure interactions, practicability of requirements and assumptions, as well as development of performance evaluation frameworks.

  13. Predissociation mechanism and spin-rotation constant of the HCO B˜ 2A' state

    NASA Astrophysics Data System (ADS)

    Lee, Shih-Huang; Chen, I.-Chia

    1995-07-01

    Formyl radicals produced from photolysis of acetaldehyde at 310 nm were supersonically cooled and detected via the B˜-X˜ transition using the laser-induced fluorescence (LIF) technique. Spectra at 0.16 cm-1 resolution and fluorescence lifetimes of HCO B˜(0,0,0), (0,0,1), and (0,1,0) levels were measured. The observed lifetimes decrease rapidly with variation of the rotational quantum number Ka from 0 to 2 but slowly with the rotational quantum number N from 0 to 8. Experimental data indicate that the B˜ state is coupled to a predissociating state via an a-type Coriolis interaction to account for the rotationally dependent lifetime for the low vibrational levels of the HCO B˜ state. Correction of the fluorescence quantum yield for individual rotational states is necessary to obtain accurate ground state populations by LIF when using the B˜-X˜ transitions. The intensity distribution of the two spin states observed implies a negative value of the spin-rotation parameter for the B˜ state, in contrast with the ground electronic state.

  14. Effects of rotational states on the c/a ratio in solid hydrogens

    DOE PAGES

    Strzhemechny, Mikhail A.; Hemley, Russell J.

    2015-04-08

    We propose an approach to the problem of lattice distortions at low temperatures and ambient pressure in the solid hydrogens in their rotational ground states that explicitly accounts for the molecular nature of the constituent particles. The model is based on the idea that the second-order rotation-related correction to the ground-state energy depends on the lattice parameters. The calculated ground-state rotation-related contributions, δgs = c/a–(8/3)1/2, are negative for all species, amounting to about –1.5×10–5 for H2 and D2, whereas for HD this contribution is about –0.6×10–3, which is roughly 50 times larger. This substantial difference stems from the fact thatmore » the rotational dynamics in the homonuclear solids and in HD differ appreciably. Furthermore, the approach can be generalized to high pressures.« less

  15. The Millimeter-Wave Spectrum of Methacrolein. Torsion-Rotation Effects in the Excited States

    NASA Astrophysics Data System (ADS)

    Zakharenko, Olena; Motiyenko, R. A.; Aviles Moreno, Juan-Ramon; Huet, T. R.

    2015-06-01

    Last year we reported the analysis of the rotational spectrum of s-trans conformer of methacrolein CH2=C(CH3)CHO in the ground vibrational state. In this talk we report the study of its low lying excited vibrational states. The study is based on room-temperature absorption spectra of methacrolein recorded in the frequency range 150 - 465 GHz using the spectrometer in Lille. The new results include assignment of the first excited torsional state (131 cm-1), and the joint analysis of the vt = 0 and vt = 1 states, that allowed us to improve the model in the frame of Rho-Axis-Method (RAM) Hamiltonian and to remove some strong correlations between parameters. Also we assigned the first excited vibrational state of the skeletal torsion mode (170 cm-1). The inverse sequence of A and E tunneling substates as well as anomalous A-E splittings observed for the rotational lines of vsk = 1 state clearly indicate a coupling between methyl torsion and skeletal torsion. However we were able to fit within experimental accuracy the rotational lines of vsk = 1 state using the RAM Hamiltonian. Because of the inversion of the A and E tunneling substates the rotational lines of the vsk = 1 states were assumed to belong to a virtual first excited torsional state. Finally, we assigned several low-Ka rotational transitions of the excited vibrational states above 200 cm-1 but their analysis is complicated by different rotation-vibration interactions. In particular there is an evidence of the Fermi-type resonance between the second excited torsional state and the first excited state of the in-plane skeletal bending mode (265 cm-1). Support from the French Laboratoire d'Excellence CaPPA (Chemical and Physical Properties of the Atmosphere) through contract ANR-10-LABX-0005 of the Programme d'Investissements d'Avenir is acknowledged. Zakharenko O. et al., 69th ISMS, 2014, TI01

  16. Nuclear structure beyond the neutron drip line. The lowest energy states in 9He via their T=5/2 isobaric analogs in 9Li

    SciTech Connect

    Uberseder, E.; Rogachev, G. V.; Goldberg, V. Z.; Koshchiy, E.; Roeder, B. T.; Alcorta, M.; Chubarian, G.; Davids, B.; Fu, C.; Hooker, J.; Jayatissa, H.; Melconian, D.; Tribble, R. E.

    2016-03-01

    The level structure of the very neutron rich and unbound 9He nucleus has been the subject of significant experimental and theoretical study. Many recent works have claimed that the two lowest energy 9He states exist with spins Jπ=1/2+and Jπ=1/2-and widths on the order of 100–200 keV. These find-ings cannot be reconciled with our contemporary understanding of nuclear structure. Our present work is the first high-resolution study with low statistical uncertainty of the relevant excitation energy range in the 8He+n system, performed via a search for the T =5/2 isobaric analog states in 9Li populated through 8He+p elastic scattering. Moreover, the present data show no indication of any narrow structures. Instead, we find evidence for a broad Jπ=1/2+state in 9He located approximately 3 MeV above the neutron decay threshold.

  17. Periodicity Signatures of Lightcurves of Active Comets in Non-Principal-Axis Rotational States

    NASA Astrophysics Data System (ADS)

    Samarasinha, Nalin H.; Mueller, Beatrice E. A.; Barrera, Jose G.

    2016-10-01

    There are two comets (1P/Halley, 103P/Hartley 2) that are unambiguously in non-principal-axis (NPA) rotational states in addition to a few more comets that are candidates for NPA rotation. Considering this fact, and the ambiguities associated with how to accurately interpret the periodicity signatures seen in lightcurves of active comets, we have started an investigation to identify and characterize the periodicity signatures present in simulated lightcurves of active comets. We carried out aperture photometry of simulated cometary comae to generate model lightcurves and analyzed them with Fourier techniques to identify their periodicity signatures. These signatures were then compared with the input component periods of the respective NPA rotational states facilitating the identification of how these periodicity signatures are related to different component periods of the NPA rotation. Ultimately, we also expect this study to shed light on why only a small fraction of periodic comets is in NPA rotational states, whereas theory indicates a large fraction of them should be in NPA states (e.g., Jewitt 1999, EMP, 79, 35). We explore the parameter space with respect to different rotational states, different orientations for the total rotational angular momentum vector, and different locations on the nucleus for the source region(s). As for special cases, we also investigate potential NPA rotational states representative of comet 103P/Hartley2, the cometary target of the EPOXI mission. The initial results from our investigation will be presented at the meeting. The NASA DDAP Program supports this work through grant NNX15AL66G.

  18. Rotational bands and isomeric states in 175Lu

    SciTech Connect

    Garrett, P E; Archer, D E; Becker, J A; Bernstein, L A; Hauschild, K; Henry, E A; McNabb, D P; Stoyer, M A; Younes, W; Johns, G D; Nelson, R O; Wilburn, W S

    2003-10-15

    Rotational bands in {sup 175}Lu have been extended through investigation with the (n,n{prime}{gamma}) reaction. Spallation neutrons bombarded Lu samples, and the resulting {gamma} rays were detected in a large-scale Compton-suppressed Ge detector array. Prompt- and delayed-{gamma}{gamma} coincidences have been used to extend most of the existing known bands, and to tentatively assign a new band, based on the 7/2{sup -}[523] configuration, from its band head to spin 13/2. The 3-quasiparticle K{sup {pi}} = 19/2{sup +} isomer is confirmed and its half life determined to be 984 {+-} 13(stat.) {+-} 30(sys.) {micro}s, in agreement with previous results.

  19. Spectroscopy of molecules in very high rotational states using an optical centrifuge.

    PubMed

    Yuan, Liwei; Toro, Carlos; Bell, Mack; Mullin, Amy S

    2011-01-01

    We have developed a high power optical centrifuge for measuring the spectroscopy of molecules in extreme rotational states. The optical centrifuge has a pulse energy that is more than 2 orders of magnitude greater than in earlier instruments. The large pulse energy allows us to drive substantial number densities of molecules to extreme rotational states in order to measure new spectroscopic transitions that are not accessible with traditional methods. Here we demonstrate the use of the optical centrifuge for measuring IR transitions of N2O from states that have been inaccessible until now. In these studies, the optical centrifuge drives N2O molecules into states with J ~ 200 and we use high resolution transient IR probing to measure the appearance of population in states with J = 93-99 that result from collisional cooling of the centrifuged molecules. High resolution Doppler broadened line profile measurements yield information about the rotational and translational energy distributions in the optical centrifuge.

  20. Rotating entangled states of an exchange-coupled dimer of single-molecule magnets

    SciTech Connect

    Owerre, S. A.

    2014-04-21

    An antiferromagnetically exchange-coupled dimer of single molecule magnets which possesses a large spin tunneling has been investigated. For this system, the ground and first excited states are entangled states, and the Hamiltonian is effectively similar to that of a two-state system at 2sth order in perturbation theory; thus this system can be mapped to an entangled pseudospin 1/2 particles. We study the effects of interaction and rotation of this system about its staggered easy-axis direction. The corresponding Hamiltonian of a rotated two-state entangled spin system is derived with its exact low-energy eigenstates and eigenvalues. We briefly discuss the effect of a dissipative environment on this rotated two-state system.

  1. State-to-state chemistry and rotational excitation of CH+ in photon-dominated regions

    NASA Astrophysics Data System (ADS)

    Faure, A.; Halvick, P.; Stoecklin, T.; Honvault, P.; Epée Epée, M. D.; Mezei, J. Zs.; Motapon, O.; Schneider, I. F.; Tennyson, J.; Roncero, O.; Bulut, N.; Zanchet, A.

    2017-07-01

    We present a detailed theoretical study of the rotational excitation of CH+ due to reactive and non-reactive collisions involving C+(2P), H2, CH+, H and free electrons. Specifically, the formation of CH+ proceeds through the reaction between C+(2P) and H_2(ν _H_2 = 1, 2), while the collisional (de)excitation and destruction of CH+ is due to collisions with hydrogen atoms and free electrons. State-to-state and initial-state-specific rate coefficients are computed in the kinetic temperature range 10-3000 K for the inelastic, exchange, abstraction and dissociative recombination processes using accurate potential energy surfaces and the best scattering methods. Good agreement, within a factor of 2, is found between the experimental and theoretical thermal rate coefficients, except for the reaction of CH+ with H atoms at kinetic temperatures below 50 K. The full set of collisional and chemical data are then implemented in a radiative transfer model. Our non-LTE calculations confirm that the formation pumping due to vibrationally excited H2 has a substantial effect on the excitation of CH+ in photon-dominated regions. In addition, we are able to reproduce, within error bars, the far-infrared observations of CH+ towards the Orion Bar and the planetary nebula NGC 7027. Our results further suggest that the population of ν _H_2 = 2 might be significant in the photon-dominated region of NGC 7027.

  2. Rotationally Inelastic Scattering of Quantum-State-Selected ND3 with Ar.

    PubMed

    Tkáč, Ondřej; Saha, Ashim K; Loreau, Jérôme; Parker, David H; van der Avoird, Ad; Orr-Ewing, Andrew J

    2015-06-11

    Rotationally inelastic scattering of ND3 with Ar is studied at mean collision energies of 410 and 310 cm(–1). In the experimental component of the study, ND3 molecules are prepared by supersonic expansion and subsequent hexapole state selection in the ground electronic and vibrational levels and in the jk(±) = 1(1) rotational level. A beam of state-selected ND3 molecules is crossed with a beam of Ar, and scattered ND3 molecules are detected in single final j′k′(±) quantum states using resonance enhanced multiphoton ionization spectroscopy. State-to-state differential cross sections for rotational-level changing collisions are obtained by velocity map imaging. The experimental measurements are compared with close-coupling quantum-mechanical scattering calculations performed using an ab initio potential energy surface. The computed DCSs agree well with the experimental measurements, confirming the high quality of the potential energy surface. The angular distributions are dominated by forward scattering for all measured final rotational and vibrational inversion symmetry states. This outcome is in contrast to our recent results for inelastic scattering of ND3 with He, where we observed significant amount of sideways and backward scattering for some final rotational levels of ND3. The differences between He and Ar collision partners are explained by differences in the potential energy surfaces that govern the scattering dynamics.

  3. Rotational Spectrum of 1,1-Difluoroethane: Internal Rotation Analysis and Structure

    NASA Astrophysics Data System (ADS)

    Villamanan, R. M.; Chen, W. D.; Wlodarczak, G.; Demaison, J.; Lesarri, A. G.; Lopez, J. C.; Alonso, J. L.

    1995-05-01

    The rotational spectrum of CH3CHF2 in its ground state was measured up to 653 GHz. Accurate rotational and centrifugal distortion constants were determined. The internal rotation splittings were analyzed using the internal axis method. An ab initio structure has been calculated and a near-equilibrium structure has been estimated using offsets derived empirically. This structure was compared to an experimental r0 structure. The four lowest excited states (including the methyl torsion) have also been assigned.

  4. State-to-state rotational phase coherence effect on the vibration-rotation band shape - An accurate quantum calculation for CO-He

    NASA Technical Reports Server (NTRS)

    Boissoles, J.; Boulet, C.; Robert, D.; Green, S.

    1989-01-01

    Accurate coupled state calculations of line coupling are performed for infrared lines of carbon monoxide perturbed by helium. Such calculations lead to both real and imaginary line couplings. For the first time, the effect of this imaginary line couplings, connected with state-to-state rotational phase coherences, on infrared band shape, is analyzed. An extension of detailed balance principle to the complex plane is suggested from the present computed off-diagonal cross sections. This allows us to understand the physical mechanism underlying the weak effect of phase coherences on CO-He infrared band shape.

  5. Collisional metastability of high rotational states of CN(X 2Σ +, ? = 0)

    NASA Astrophysics Data System (ADS)

    Hay, S.; Shokoohi, F.; Callister, S.; Wittig, C.

    1985-07-01

    CN(X 2Σ +, v'' = 0) high rotational states relax slowly via 300 K collisions with Ar and Kr. Relaxation decreases with increasing rotation, and the partially relaxed distributions are bimodal, with low N'' thermalized (300 K), and N'' = 80 unrelaxed after 1000 collisions. Relaxation by N 2, CO, and Xe is similar to Ar and Kr, but more efficient. He and NO remove many quanta in a single collision.

  6. Some questions on the Coriolis force, the structure of rotational states and the IBM

    SciTech Connect

    Khoo, T.L.

    1980-01-01

    Participants in the Round Table Discussion at the International Conference on Band Structure and Nuclear Dynamics were to make editorial comments on what transpired during the conference. This paper contains comments of one panel member on questions which he feels were not addressed during the meeting. His comments concern the Coriolis force in rotating nuclei and its relation to the nucleon-nucleon interaction, the microscopic origin of rotational states, and the interacting boson model. (RWR)

  7. The infrared rotation-vibration spectrum of dicyanoacetylene: The ground and v9 = 1 state rotational constants

    NASA Astrophysics Data System (ADS)

    Winther, F.; Schönhoff, M.; LePrince, R.; Guarnieri, A.; Bruget, D. N.; McNaughton, D.

    1992-03-01

    The bands ν5, ν6 + ν8, ν7 + ν8, ν6 + ν9, and ν8 of NCCCCN have been investigated in the gas phase with a resolution of 0.003 cm -1. The ground state rotational constants B0 = 0.04458699(10) cm -1 and D0 = 1.049(4) × 10 -9 cm -1 have been determined, together with the constants and the vibrational frequencies for the above bands. Several hot bands from the v9 = 1 state were analyzed to give B9 = 0.04468316(18) cm -1, D9 = 1.117(5) × 10 -9 cm -1, q9 = 3.85(2) × 10 -5 cm -1, and q9 J = 2.4(7) × 10 -11 cm -1. The bond lengths of NCCCCN correspond very closely to those of HCCCCCN.

  8. Using a Spreadsheet to Solve the Schro¨dinger Equations for the Energies of the Ground Electronic State and the Two Lowest Excited States of H[subscript2

    ERIC Educational Resources Information Center

    Ge, Yingbin; Rittenhouse, Robert C.; Buchanan, Jacob C.; Livingston, Benjamin

    2014-01-01

    We have designed an exercise suitable for a lab or project in an undergraduate physical chemistry course that creates a Microsoft Excel spreadsheet to calculate the energy of the S[subscript 0] ground electronic state and the S[subscript 1] and T[subscript 1] excited states of H[subscript 2]. The spreadsheet calculations circumvent the…

  9. Using a Spreadsheet to Solve the Schro¨dinger Equations for the Energies of the Ground Electronic State and the Two Lowest Excited States of H[subscript2

    ERIC Educational Resources Information Center

    Ge, Yingbin; Rittenhouse, Robert C.; Buchanan, Jacob C.; Livingston, Benjamin

    2014-01-01

    We have designed an exercise suitable for a lab or project in an undergraduate physical chemistry course that creates a Microsoft Excel spreadsheet to calculate the energy of the S[subscript 0] ground electronic state and the S[subscript 1] and T[subscript 1] excited states of H[subscript 2]. The spreadsheet calculations circumvent the…

  10. Comments on the Rotational State and Non-Gravitational Forces of Comet 46/WIRTANEN. Revised

    NASA Technical Reports Server (NTRS)

    Samarasinha, Nalin H.; Mueller, Beatrice E. A.; Belton, Michael J. S.

    1995-01-01

    We apply our experience of modeling the rotational state and non-gravitational forces of comet 1 P/Halley and other comets to comet 46P/Wirtanen. While the paucity of physical data on 46P/Wirtanen makes this process somewhat speculative, this comet's place as target for the important Rosetta mission gives significance to such a study. Our arguments are based on the summary of observational data provided by Jorda and Rickman (1995) and a comparative study of the behavior of other periodic comets. We find 46P/Wirtanen to have a level of surface activity relative to its mass that is dynamically more akin to that found in comet 1 P/Halley than in a typical periodic comet. We show through an illustrative numerical example that this apparent fact should likely lead to an excited spin state for this comet and that significant changes in the spin period could occur in a single pass through perihelion. We argue that the available observations are not sufficient to substantiate the claim of Jorda and Rickman (1995) that the nucleus is undergoing retrograde rotation and it is possible that the rotation is either prograde as well as retrograde. The substantial requirements that must be placed on any future observing program necessary to determine the precise rotational state are outlined. We advocate an extended (approx. two month) southern hemisphere observing campaign to determine the nuclear rotational state in 1996 if possible before activity turns on.

  11. Rotation vibration energy level clustering in the XB1 ground electronic state of PH2

    NASA Astrophysics Data System (ADS)

    Yurchenko, S. N.; Thiel, W.; Jensen, Per; Bunker, P. R.

    2006-10-01

    We use previously determined potential energy surfaces for the Renner-coupled XB1 and AA1 electronic states of the phosphino (PH 2) free radical in a calculation of the energies and wavefunctions of highly excited rotational and vibrational energy levels of the X˜ state. We show how spin-orbit coupling, the Renner effect, rotational excitation, and vibrational excitation affect the clustered energy level patterns that occur. We consider both 4-fold rotational energy level clustering caused by centrifugal distortion, and vibrational energy level pairing caused by local mode behaviour. We also calculate ab initio dipole moment surfaces for the X˜ and A˜ states, and the X˜-A˜ transition moment surface, in order to obtain spectral intensities.

  12. Effect of the equation of state on the maximum mass of differentially rotating neutron stars

    NASA Astrophysics Data System (ADS)

    Studzińska, A. M.; Kucaba, M.; Gondek-Rosińska, D.; Villain, L.; Ansorg, M.

    2016-12-01

    Knowing the value of the maximum mass of a differentially rotating relativistic star is a key step towards the understanding of the signals to be expected from the merger of binary neutron stars, one of the most awaited alternative sources of gravitational waves after binary black holes. In this paper, we study the effects of differential rotation and of the equation of state on the maximum mass of rotating neutron stars modelled as relativistic polytropes with various adiabatic indices. Calculations are performed using a highly accurate numerical code, based on a multidomain spectral method. We thoroughly explore the parameter space and determine how the maximum mass depends on the stiffness, on the degree of differential rotation and on the maximal density, taking into account all the types of solutions that were proven to exist in a preceding paper. The highest increase with respect to the maximum mass for non-rotating stars with the same equation of state is reached for a moderate stiffness. With differential rotation, the maximum mass can even be 3-4 times higher than it is for static stars. This result may have important consequences for the gravitational wave signal from coalescing neutron star binaries or for some supernovae events.

  13. Microwave lens effect for the J = 0 rotational state of CH3CN

    NASA Astrophysics Data System (ADS)

    Spieler, Steffen; Zhong, Wei; Djuricanin, Pavle; Nourbakhsh, Omid; Gerhardt, Ilja; Enomoto, Katsunari; Stienkemeier, Frank; Momose, Takamasa

    2013-07-01

    We demonstrate the manipulation of the translational motion of a polar molecule in its J = 0 rotational ground state by the microwave (MW) dipole force combined with a counter-rotating nozzle. A cold molecular beam of CH3CN seeded in Kr with a longitudinal velocity of about 100 m s-1 was created by a pulsed counter-rotating nozzle. The cold beam was then introduced into a cylindrical MW cavity, in which a standing wave, TM01p mode MW field, nearly resonant to the |J, K> = |1, 0> ← |0, 0> rotational transition of CH3CN was created. By choosing an appropriate MW frequency, we successfully observed focusing and deflection of the cold beam of CH3CN due to the lens effect of the MW standing wave. The present result indicates that the combination of a counter-rotating nozzle and an MW cavity will be a versatile method for making cold and ultracold ensembles of various polar molecules in their rotational ground state.

  14. The rotational state of Mercury after four years of MESSENGER observations

    NASA Astrophysics Data System (ADS)

    Stark, Alexander; Oberst, Jürgen; Preusker, Frank; Hussmann, Hauke

    2017-04-01

    We measured the rotational state of Mercury with orbital data from NASA's MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. We use accurate co-registration of digital terrain models from stereo images (stereo DTMs) and laser altimeter data to measure the orientation of the rotation axis, the libration amplitude and the mean rotation rate with improved precision. In contrast to our previous study, we use the full four years of near-continuous Mercury Laser Altimeter (MLA) observations and stereo DTMs with a higher spatial coverage. We confirm a large libration amplitude and a mean rotation rate which is significantly higher than the assumed resonant rotation rate based on a perfect 3:2 spin orbit resonance. The estimated orientation of the rotation axis is consistent with the assumption that Mercury occupies a Cassini state. We compare our estimates with values based on Earth-based observations and MESSENGER radio science. Our results confirm that Mercury possesses a liquid outer core and we discuss further implications of our estimates on the interior structure of the planet.

  15. Pure quantum states of a neutrino with rotating spin in dense magnetized matter

    NASA Astrophysics Data System (ADS)

    Arbuzova, E. V.; Lobanov, A. E.; Murchikova, E. M.

    2010-02-01

    The problem of neutrino spin rotation in dense matter and in strong electromagnetic fields is solved in accordance with the basic principles of quantum mechanics. We obtain a complete system of wave functions for a massive Dirac neutrino with an anomalous magnetic moment which are the eigenfunctions of the kinetic momentum operator and have the form of nonspreading wave packets. These wave functions enable one to consider the states of neutrino with rotating spin as pure quantum states and can be used for calculating probabilities of various processes with the neutrino in the framework of the Furry picture.

  16. The {ital T}{sub 1}({ital n}{pi}{asterisk}){l_arrow}{ital S}{sub 0} laser induced phosphorescence excitation spectrum of acetaldehyde in a supersonic free jet: Torsion and wagging potentials in the lowest triplet state

    SciTech Connect

    Liu, H.; Lim, E.C.; Munoz-Caro, C.; Nino, A.; Judge, R.H.; Moule, D.C.

    1996-08-01

    The laser induced {ital T}{sub 1}({ital n}{pi}{asterisk}){l_arrow}{ital S}{sub 0} phosphorescence excitation spectrum of jet-cooled acetaldehyde has been observed for the first time with a rotating slit nozzle excitation system. The vibronic origins were fitted to a set of levels that were obtained from a Hamiltonian that employed flexible torsion-wagging large amplitude coordinates. The potential surface extracted from the fitting procedure yielded barriers to torsion and inversion of 609.68 and 869.02 cm{sup {minus}1}, respectively. Minima in the potential hypersurface at {theta}=61.7{degree} and {alpha}=42.2{degree} defined the equilibrium positions for the torsion and wagging coordinates. A comparison to the corresponding {ital S}{sub 1}-state parameters showed that the torsion barrier (in cm{sup {minus}1}) does not greatly change, {ital S}{sub 1}/{ital T}{sub 1}=710.8/609.7, whereas the barrier height for the wagging-inversion barrier increases dramatically, 574.4/869.0. {copyright} {ital 1996 American Institute of Physics.}

  17. The rotational dynamics of Mercury and the state of its core

    NASA Technical Reports Server (NTRS)

    Peale, S. J.

    1988-01-01

    Data on the rotational dynamics of Mercury are examined together with possible events that could lead to the current state of rotation. It is shown that the dynamical evolution of Mercury's spin angular momentum controlled by the dissipative processes of tidal friction and relative motion between a solid mantle and a liquid core would lead naturally to the current state of rotation of the Mercury planet. To investigate the possibility that Mercury has a molten core, an experiment is designed for the measurement of the core properties of Mercury. It is shown that it is technically feasible to measure the four parameters necessary for the determination of the existence and the extent of a Mercurian molten core, including the amplitude of the physical vibration about the resonance spin rate, the obliquity, and the gravitational harmonic coefficients.

  18. Simultaneous Evaluation of Multiple Rotationally Excited States of Floppy Molecules Using Diffusion Monte Carlo

    NASA Astrophysics Data System (ADS)

    McCoy, Anne B.; Ford, Jason E.; Marlett, Melanie L.; Petit, Andrew S.

    2014-06-01

    In this work, an extension to diffusion Monte Carlo (DMC) is proposed, allowing for the simultaneous calculation of the energy and wave function of multiple rotationally excited states of floppy molecules. The total wave function is expanded into a set of Dirac δ-functions called walkers, while the rotational portion of the wave function is expanded in a symmetric top basis set. Each walker is given a rotational state vector containing coefficients for all states of interest. The positions of the atoms and the coefficients in the state vector evolve according to the split operator approximation of the quantum propagator. The method was benchmarked by comparing calculated rotation-vibration energies for H_3^+, H_2D^+, and H_3O^+ to experimental values. For low to moderate values of J, the resulting energies are within the statistical uncertainty of the calculation. Rotation-vibration coupling is captured through flexibility introduced in the form of the vibrational wave function. This coupling is found to increase with increasing J-values. Based on the success achieved through these systems, the method was applied to CH_5^+ and its deuterated isotopologues for v = 0, J ≥ 10. Based on these calculations, the energy level structure of CH_5^+ is found to resemble that for a of a spherical top, and excitations up to J = 10 displayed insignificant rotation-vibration coupling. Extensions of this approach that explicitly account for vibrations will also be discussed. ` A. S. Petit, J. E. Ford and A. B. McCoy, J. Phys. Chem. A, in press, K. D. Jordan Festschrift, DOI: 10.1021/jp408821a

  19. Rotationally Resolved Photoelectron Spectroscopic Study of the tilde{A}^+ State of H_2O^+

    NASA Astrophysics Data System (ADS)

    Lauzin, Clément; Gans, Berenger; Jacovella, Ugo; Merkt, Frederic

    2016-06-01

    This talk will present the analysis of the rotationally resolved pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE) photoelectron spectrum of H_2O and will be focussed on the tilde{A}^+←tilde{X} transitions. H_2O^+ in the tilde{A}^+ state is predicted to be linear. The sensitivity and the high resolution of PFI- ZEKE photoelectron spectroscopy allowed us to observe the rotational structure of low bending vibrational levels of the tilde{A}^+ state of H_2O^+ from the tilde{X} ground electronic state of H_2O. The assignment of the rotational structure of ionic levels previously observed by optical spectroscopy of the tilde{A}^+ - tilde{X}^+ band system of H_2O^+ will be presented and the intensity distribution of the photoelectron spectrum will be discussed in terms of the even or odd nature of the orbital angular momentum quantum number l of the photoelectron. Tentative assignments will be presented for several low-lying vibrational levels of the tilde{A}^+ state and compared with theoretical predictions ^c. They will also be discussed in terms of the rotational structure of higher tilde{A}^+ vibrational levels of the same symmetry. M. Brommer, B. Weis, B. Follmeg, P. Rosmus, S. Carter, N. C. Handy, H. J. Werner, and P. J. Knowles, J. Chem. Phys. 98, 5222 (1993) H. Lew, Can. J. Phys. 54, 2028 (1976).

  20. Adsorbate-induced absorption redshift in an organic-inorganic cluster conjugate: Electronic effects of surfactants and organic adsorbates on the lowest excited states of a methanethiol-CdSe conjugate

    NASA Astrophysics Data System (ADS)

    Liu, Christopher; Chung, Sang-Yoon; Lee, Sungyul; Weiss, Shimon; Neuhauser, Daniel

    2009-11-01

    Bioconjugated CdSe quantum dots are promising reagents for bioimaging applications. Experimentally, the binding of a short peptide has been found to redshift the optical absorption of nanoclusters [J. Tsay et al., J. Phys. Chem. B 109, 1669 (2005)]. This study examines this issue by performing density functional theory (DFT) and time-dependent-DFT calculations to study the ground state and low-lying excited states of (CdSe)6[SCH3]-, a transition metal complex built by binding methanethiolate to a CdSe molecular cluster. Natural bond orbital results show that the redshift is caused by ligand-inorganic cluster orbital interaction. The highest occupied molecular orbital (HOMO) of (CdSe)6 is dominated by selenium 4p orbitals; in contrast, the HOMO of (CdSe)6[SCH3]- is dominated by sulfur 3p orbitals. This difference shows that [SCH3]- binding effectively introduces filled sulfur orbitals above the selenium 4p orbitals of (CdSe)6. The resulting smaller HOMO-LUMO gap of (CdSe)6[SCH3]- indeed leads to redshifts in its excitation energies compared to (CdSe)6. In contrast, binding of multiple NH3 destabilizes cadmium 5p orbitals, which contribute significantly to the lowest unoccupied molecular orbital (LUMO) of (CdSe)6, while leaving the selenium 4p orbitals near the HOMO relatively unaffected. This has the effect of widening the HOMO-LUMO gap of (CdSe)6ṡ6NH3 compared to (CdSe)6. As expected, the excitation energies of the passivated (CdSe)6ṡ6NH3 are also blueshifted compared to (CdSe)6. As far as NH3 is a faithful representation of a surfactant, the results clearly illustrate the differences between the electronic effects of an alkylthiolate versus those of surfactant molecules. Surface passivation of (CdSe)6[SCH3]- is then simulated by coating it with multiple NH3 molecules. The results suggest that the [SCH3]- adsorption induces a redshift in the excitation energies in a surfactant environment.

  1. Adsorbate-induced absorption redshift in an organic-inorganic cluster conjugate: Electronic effects of surfactants and organic adsorbates on the lowest excited states of a methanethiol-CdSe conjugate.

    PubMed

    Liu, Christopher; Chung, Sang-Yoon; Lee, Sungyul; Weiss, Shimon; Neuhauser, Daniel

    2009-11-07

    Bioconjugated CdSe quantum dots are promising reagents for bioimaging applications. Experimentally, the binding of a short peptide has been found to redshift the optical absorption of nanoclusters [J. Tsay et al., J. Phys. Chem. B 109, 1669 (2005)]. This study examines this issue by performing density functional theory (DFT) and time-dependent-DFT calculations to study the ground state and low-lying excited states of (CdSe)(6)[SCH(3)](-), a transition metal complex built by binding methanethiolate to a CdSe molecular cluster. Natural bond orbital results show that the redshift is caused by ligand-inorganic cluster orbital interaction. The highest occupied molecular orbital (HOMO) of (CdSe)(6) is dominated by selenium 4p orbitals; in contrast, the HOMO of (CdSe)(6)[SCH(3)](-) is dominated by sulfur 3p orbitals. This difference shows that [SCH(3)](-) binding effectively introduces filled sulfur orbitals above the selenium 4p orbitals of (CdSe)(6). The resulting smaller HOMO-LUMO gap of (CdSe)(6)[SCH(3)](-) indeed leads to redshifts in its excitation energies compared to (CdSe)(6). In contrast, binding of multiple NH(3) destabilizes cadmium 5p orbitals, which contribute significantly to the lowest unoccupied molecular orbital (LUMO) of (CdSe)(6), while leaving the selenium 4p orbitals near the HOMO relatively unaffected. This has the effect of widening the HOMO-LUMO gap of (CdSe)(6)6NH(3) compared to (CdSe)(6). As expected, the excitation energies of the passivated (CdSe)(6)6NH(3) are also blueshifted compared to (CdSe)(6). As far as NH(3) is a faithful representation of a surfactant, the results clearly illustrate the differences between the electronic effects of an alkylthiolate versus those of surfactant molecules. Surface passivation of (CdSe)(6)[SCH(3)](-) is then simulated by coating it with multiple NH(3) molecules. The results suggest that the [SCH(3)](-) adsorption induces a redshift in the excitation energies in a surfactant environment.

  2. Superposition states of ultracold bosons in rotating rings with a realistic potential barrier

    SciTech Connect

    Nunnenkamp, Andreas; Rey, Ana Maria; Burnett, Keith

    2011-11-15

    In a recent paper [Phys. Rev. A 82, 063623 (2010)] Hallwood et al. argued that it is feasible to create large superposition states with strongly interacting bosons in rotating rings. Here we investigate in detail how the superposition states in rotating-ring lattices depend on interaction strength and barrier height. With respect to the latter we find a trade-off between energy gap and quality of the superposition state. Most importantly, we go beyond the {delta}-function approximation for the barrier potential and show that the energy gap decreases exponentially with the number of particles for weak barrier potentials of finite width. These are crucial issues in the design of experiments to realize superposition states.

  3. Direct measurements of rotation-specific, state-to-state vibrational energy transfer in highly vibrationally excited acetylene

    NASA Astrophysics Data System (ADS)

    Tobiason, J. D.; Utz, A. L.; Crim, F. F.

    1994-07-01

    Vibrational overtone excitation followed by laser-induced fluorescence detection allows the direct measurement of rotationally resolved vibrational energy transfer rates in highly vibrationally excited acetylene molecules. We detect transfer from the initial, even rotational states Ji=0-22 of 3ν3 (ν˜0=9640 cm-1) to the nearly isoenergetic final state Jf=4 of ν1+ν2+ν3+2ν4, l=0 (ν˜0=9668 cm-1). For these pathways, we observe changes in energy of up to ‖ΔE‖=530 cm-1 (≊2.5 kT) and in angular momentum quantum number of up to ‖ΔJ‖=18 in a single collision, and we measure state-to-state rate constants of about 0.1 μs-1Torr-1 (160 collisions). Measurements under single collision conditions ensure that the vibrational relaxation is free of any rotational equilibration. By applying detailed balance and summing the resulting reverse rate constants, we obtain a total rate constant of 1.3 μs-1Torr-1 (13 collisions) for transfer from ν1+ν2+ν3+2ν4, l=0, Jf=4 to all final rotational states in 3ν3. The energy transfer rate between two specific rovibrational states decreases exponentially with increasing energy difference. The vibrational relaxation does not have a strong angular momentum dependence in general, but transfer from the initial rotational states 3ν3, J=16, and J=20 is anomalously fast. The Fermi resonance of 3ν3 and ν1+ν2+ν3+2ν4, l=0 appears to enhance collisional transfer between the pair by a factor of 10 or more over that for uncoupled levels, and the anomalously fast transfer from initial states 3ν3, J=16 and 20 is probably due to their relatively strong, rotation-specific intramolecular coupling with other nearby, unobserved vibrational states.

  4. Mathematical modeling of electroless nickel deposition at steady state using rotating disk electrode

    SciTech Connect

    Kim, Y.S.; Sohn, H.J.

    1996-02-01

    Mathematical modeling of electroless nickel deposition was performed to predict the phosphorus content in Ni-P alloy film at steady state using the rotating disk system. The model consists of steady-state convective diffusion equations with nonlinear boundary conditions and overpotential equations satisfying the mixed potential theory. The weight percent of phosphorus predicted in Ni-P alloy agrees well with the experimental values within the experimental conditions carried out.

  5. Diffraction pattern by rotated conical tracks in solid state nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Stevanovic, N.; Markovic, V. M.

    2016-06-01

    The method for determination of diffraction pattern for irregular 3D objects with application on rotated conical tracks in solid state nuclear track detector (SSNTD) wasdescribed in this paper. The model can be applied for different types of the diffraction (Fresnel, Fraunhofer) and arbitrary shapes of the obstacle. By applying the developed model on conical tracks it was fond that diffraction pattern strongly depends from radius, length and rotation angle of the conical tracks. These dependences were investigated in this paper and results can be applied for determination of inner tracks structure via diffraction pattern.

  6. Calcific tendinitis of the rotator cuff: state of the art in diagnosis and treatment.

    PubMed

    Merolla, Giovanni; Singh, Sanjay; Paladini, Paolo; Porcellini, Giuseppe

    2016-03-01

    Calcific tendinitis is a painful shoulder disorder characterised by either single or multiple deposits in the rotator cuff tendon. Although the disease subsides spontaneously in most cases, a subpopulation of patients continue to complain of pain and shoulder dysfunction and the deposits do not show any signs of resolution. Although several treatment options have been proposed, clinical results are controversial and often the indication for a given therapy remains a matter of clinician choice. Herein, we report on the current state of the art in the pathogenesis, diagnosis and treatment of calcific tendinitis of the rotator cuff.

  7. Simple solutions of fireball hydrodynamics for rotating and expanding triaxial ellipsoids and final state observables

    NASA Astrophysics Data System (ADS)

    Nagy, M. I.; Csörgő, T.

    2016-12-01

    We present a class of analytic solutions of nonrelativistic fireball hydrodynamics for a fairly general class of equation of state. The presented solution describes the expansion of a triaxial ellipsoid that rotates around one of its principal axes. We calculate the hadronic final state observables such as single-particle spectra, directed, elliptic, and third flows, as well as two-particle Bose-Einstein (also named HBT) correlations and corresponding radius parameters, utilizing simple analytic formulas. The final tilt angle of the fireball, an important observable quantity, is shown to be not independent of its exact definition: one gets different tilt angles from the geometrical anisotropies, from the single-particle spectra, and from HBT measurements. Taken together, the tilt angle in the momentum space and in the relative momentum or HBT variable may be sufficient for the determination of the magnitude of the rotation of the fireball. We argue that observing this rotation and its dependence on collision energy could characterize the softest point of the equation of state. Thus determining the rotation may be a powerful tool for the experimental search for the critical point in the phase diagram of strongly interacting matter.

  8. Equation of state effects on gravitational waves from rotating core collapse

    NASA Astrophysics Data System (ADS)

    Richers, Sherwood; Ott, Christian D.; Abdikamalov, Ernazar; O'Connor, Evan; Sullivan, Chris

    2017-03-01

    Gravitational waves (GWs) generated by axisymmetric rotating collapse, bounce, and early postbounce phases of a galactic core-collapse supernova are detectable by current-generation gravitational wave observatories. Since these GWs are emitted from the quadrupole-deformed nuclear-density core, they may encode information on the uncertain nuclear equation of state (EOS). We examine the effects of the nuclear EOS on GWs from rotating core collapse and carry out 1824 axisymmetric general-relativistic hydrodynamic simulations that cover a parameter space of 98 different rotation profiles and 18 different EOS. We show that the bounce GW signal is largely independent of the EOS and sensitive primarily to the ratio of rotational to gravitational energy, T /|W | , and at high rotation rates, to the degree of differential rotation. The GW frequency (fpeak˜600 - 1000 Hz ) of postbounce core oscillations shows stronger EOS dependence that can be parametrized by the core's EOS-dependent dynamical frequency √{G ρ¯ c } . We find that the ratio of the peak frequency to the dynamical frequency fpeak/√{G ρc ¯ } follows a universal trend that is obeyed by all EOS and rotation profiles and that indicates that the nature of the core oscillations changes when the rotation rate exceeds the dynamical frequency. We find that differences in the treatments of low-density nonuniform nuclear matter, of the transition from nonuniform to uniform nuclear matter, and in the description of nuclear matter up to around twice saturation density can mildly affect the GW signal. More exotic, higher-density physics is not probed by GWs from rotating core collapse. We furthermore test the sensitivity of the GW signal to variations in the treatment of nuclear electron capture during collapse. We find that approximations and uncertainties in electron capture rates can lead to variations in the GW signal that are of comparable magnitude to those due to different nuclear EOS. This emphasizes the

  9. A novel experiment using rotating magnetic fields to study the pumping spin states in molecular magnets

    NASA Astrophysics Data System (ADS)

    Hernandez-Minguez, Alberto; Macia, Ferran; Hernandez, Joan Manel; Carbonell, Carla; Amigó, Roger; Tejada, Javier

    2008-03-01

    We report here a new experimental technique to monitor spin population dynamics in molecular magnets. This deals with a huge rotating magnetic field initially applied along the easy magnetization direction, z--axis, that rotates with components parallel and perpendicular to the z axis. This technique allows us to probe spin relaxation on reasonably fast time scales detecting the inversion of the whole spin states. The population of spin levels depends on the frequency of the rotating magnetic field. This very new technique could help to carry out new experiments in a number of different fields, broadening substantially the scope of their use until now. A Hern'andez-M'inguez et al., Appl. Phys. Lett. 91, 202502 (2007)

  10. Hindered and modulated rotational states and spectra of adsorbed diatomic molecules

    NASA Astrophysics Data System (ADS)

    Shih, Y. T.; Chuu, D. S.; Mei, W. N.

    1996-10-01

    Both vertical and horizontal adsorption configurations of a diatomic molecule were modeled as the rigid rotor with which the spatial motion was confined by a finite conical well. In addition to the polar hindering potential, a sinusoidal azimuthal modulation, which bears the local symmetry of the adsorption site, was incorporated. Eigenfunctions for different models were expressed analytically in terms of the hypergeometric functions, and eigenvalues were solved numerically. We found that the rotational energy levels exhibit oscillatory behavior when plotted as functions of the hindrance angle. This particular phenomenon was interpreted as the occurrence of resonance transmission of the rotor wave function at certain hindrance condition. We also found that the rotational levels were grouped into bands when the azimuthal modulation strength was increased. The solutions were used to calculate the rotational-state distribution of desorbed molecules, and agreement with the previous experiment was obtained.

  11. Hindered and modulated rotational states and spectra of adsorbed diatomic molecules

    SciTech Connect

    Shih, Y.T.; Chuu, D.S.; Mei, W.N.

    1996-10-01

    Both vertical and horizontal adsorption configurations of a diatomic molecule were modeled as the rigid rotor with which the spatial motion was confined by a finite conical well. In addition to the polar hindering potential, a sinusoidal azimuthal modulation, which bears the local symmetry of the adsorption site, was incorporated. Eigenfunctions for different models were expressed analytically in terms of the hypergeometric functions, and eigenvalues were solved numerically. We found that the rotational energy levels exhibit oscillatory behavior when plotted as functions of the hindrance angle. This particular phenomenon was interpreted as the occurrence of resonance transmission of the rotor wave function at certain hindrance condition. We also found that the rotational levels were grouped into bands when the azimuthal modulation strength was increased. The solutions were used to calculate the rotational-state distribution of desorbed molecules, and agreement with the previous experiment was obtained. {copyright} {ital 1996 The American Physical Society.}

  12. Rotational spectrum of the AgS radical in the X2Πi state

    NASA Astrophysics Data System (ADS)

    Okabayashi, Toshiaki; Oya, Atsushi; Yamamoto, Takuya; Mizuguchi, Den-ichiro; Tanimoto, Mitsutoshi

    2016-11-01

    The rotational spectrum of the AgS radical in the X2Πi state was observed using a source-modulation microwave spectrometer. This radical was generated in a free-space cell by a DC glow discharge under Ar-diluted H2S. Silver atoms were supplied by sputtering from silver sheets placed on the inner surface of the stainless steel cathode. Rotational transitions from J = 7.5 - 6.5 to 39.5 - 38.5 were measured in the 58-310 GHz region. Rotational, centrifugal distortion, and several fine- and hyperfine-structure constants were determined by least-squares analysis. Other spectroscopic parameters such as the dissociation energy, vibrational wavenumber, and equilibrium bond length were also derived from the determined molecular constants. In addition, some electronic properties were estimated from the fine- and hyperfine-structure constants.

  13. Infrared spectroscopy of molecular ions in selected rotational and spin-orbit states

    NASA Astrophysics Data System (ADS)

    Jacovella, U.; Agner, J. A.; Schmutz, H.; Deiglmayr, J.; Merkt, F.

    2016-07-01

    First results are presented obtained with an experimental setup developed to record IR spectra of rotationally state-selected ions. The method we use is a state-selective version of a method developed by Schlemmer et al. [Int. J. Mass Spectrom. 185, 589 (1999); J. Chem. Phys. 117, 2068 (2002)] to record IR spectra of ions. Ions are produced in specific rotational levels using mass-analyzed-threshold-ionization spectroscopy. The state-selected ions generated by pulsed-field ionization of Rydberg states of high principal quantum number (n ≈ 200) are extracted toward an octupole ion guide containing a neutral target gas. Prior to entering the octupole, the ions are excited by an IR laser. The target gas is chosen so that only excited ions react to form product ions. These product ions are detected mass selectively as a function of the IR laser wavenumber. To illustrate this method, we present IR spectra of C 2 H2 + in selected rotational levels of the 2Πu,3/2 and 2Πu,1/2 spin-orbit components of the vibronic ground state.

  14. Coulomb excitation of ground band rotational states in /sup 249/Bk

    SciTech Connect

    Bemis, C.E. Jr.; McGowan, F.K.; Ford, J.L.C. Jr.; Milner, W.T.; Robinson, R.L.; Stelson, P.H.

    1982-03-01

    Coulomb-excitation probabilities for the first few members of the 7/2/sup +/(633up-arrow) ground-state rotational band in /sup 249/Bk have been determined with 17.06-MeV /sup 4/He ions. These previously know excited states include the 9/2/sup +/ (41.8-keV), 11/2/sup +/ (93.7-keV), and 13/2/sup +/ (155.8-keV) members of the 7/2/sup +/(633up-arrow) band. Within experimental uncertainties, the Coulomb-excitation probabilities for these rotational states are reproduced by calculated values when only E2 excitations are considered with an intrinsic quadrupole moment, Q/sub 20/, of 12.70 +- 0.24 eb in the rigid rotor limit. The deduced ground-state spectroscopic quadrupole moment is 5.93 +- 0.11 eb. Intraband M1 transition rates have been deduced by combining the Q/sub 20/ result with other experimental data. Within the rotational model, a ground-state magnetic moment of +3.45 +- 0.10 ..mu../sub N/ is indicated.

  15. Semiclassical description of quantum rotator in terms of SU(2) coherent states

    NASA Astrophysics Data System (ADS)

    Gitman, D. M.; Petrusevich, D. A.; Shelepin, A. L.

    2013-10-01

    We introduce coordinates of the rigid body (rotator) using mutual positions between body-fixed and space-fixed reference frames. Wave functions that depend on such coordinates can be treated as scalar functions of the group SU(2). Irreducible representations of the group SU(2) × SU(2) in the space of such functions describe their possible transformations under independent rotations of the both reference frames. We construct sets of the corresponding group SU(2) × SU(2) Perelomov coherent states (CS) with a fixed angular momentum j of the rotator as special orbits of the latter group. Minimization of different uncertainty relations is discussed. The classical limit corresponds to the limit j → ∞. Considering Hamiltonians of rotators with different characteristics, we study the time evolution of the constructed CS. In some cases, the CS time evolution is completely or partially reduced to their parameter time evolution. If these parameters are chosen as Euler angles, then they obey the Euler equations in the classical limit. Quantum corrections to the motion of the quantum rotator can be found from exact equations on the CS parameters.

  16. ROTATION STATE OF COMET 103P/HARTLEY 2 FROM RADIO SPECTROSCOPY AT 1 mm

    SciTech Connect

    Drahus, Michal; Jewitt, David; Guilbert-Lepoutre, Aurelie; Waniak, Waclaw; Hoge, James; Lis, Dariusz C.; Yoshida, Hiroshige; Peng, Ruisheng; Sievers, Albrecht

    2011-06-10

    The nuclei of active comets emit molecules anisotropically from discrete vents. As the nucleus rotates, we expect to observe periodic variability in the molecular emission line profiles, which can be studied through millimeter/submillimeter spectroscopy. Using this technique we investigated the HCN atmosphere of comet 103P/Hartley 2, the target of NASA's EPOXI mission, which had an exceptionally favorable apparition in late 2010. We detected short-term evolution of the spectral line profile, which was stimulated by the nucleus rotation, and which provides evidence for rapid deceleration and excitation of the rotation state. The measured rate of change in the rotation period is +1.00 {+-} 0.15 minutes day{sup -1} and the period itself is 18.32 {+-} 0.03 hr, both applicable at the epoch of the EPOXI encounter. Surprisingly, the spin-down efficiency is lower by two orders of magnitude than the measurement in comet 9P/Tempel 1 and the best theoretical prediction. This secures rotational stability of the comet's nucleus during the next few returns, although we anticipate a catastrophic disruption from spin-up as its ultimate fate.

  17. Training echo state networks for rotation-invariant bone marrow cell classification.

    PubMed

    Kainz, Philipp; Burgsteiner, Harald; Asslaber, Martin; Ahammer, Helmut

    2017-01-01

    The main principle of diagnostic pathology is the reliable interpretation of individual cells in context of the tissue architecture. Especially a confident examination of bone marrow specimen is dependent on a valid classification of myeloid cells. In this work, we propose a novel rotation-invariant learning scheme for multi-class echo state networks (ESNs), which achieves very high performance in automated bone marrow cell classification. Based on representing static images as temporal sequence of rotations, we show how ESNs robustly recognize cells of arbitrary rotations by taking advantage of their short-term memory capacity. The performance of our approach is compared to a classification random forest that learns rotation-invariance in a conventional way by exhaustively training on multiple rotations of individual samples. The methods were evaluated on a human bone marrow image database consisting of granulopoietic and erythropoietic cells in different maturation stages. Our ESN approach to cell classification does not rely on segmentation of cells or manual feature extraction and can therefore directly be applied to image data.

  18. Lowest matric potential in quartz: Metadynamics evidence

    NASA Astrophysics Data System (ADS)

    Zhang, Chao; Dong, Yi; Liu, Zhen

    2017-02-01

    The lowest matric potential is an important soil property characterizing the strength of retaining water molecules and a key parameter in defining a complete soil water retention curve. However, the exact value of the lowest matric potential is still unclear and cannot be measured due to the limitation of current experimental technology. In this study, a general theoretical framework based on metadynamics was proposed to determine the lowest matric potential in quartz minerals. The matric potential was derived from partial volume free energy and can be further calculated by the difference between the adsorption free energy and self-hydration free energy. Metadynamics was employed to enhance molecular dynamics for determination of the adsorption free energy. In addition to the water-mineral interaction, the adsorptive water layer structure was identified as an important mechanism that may lower the free energy of water molecules. The lowest matric potential for quartz mineral was found as low as -2.00 GPa.

  19. Bergman kernel from the lowest Landau level

    NASA Astrophysics Data System (ADS)

    Klevtsov, S.

    2009-07-01

    We use path integral representation for the density matrix, projected on the lowest Landau level, to generalize the expansion of the Bergman kernel on Kähler manifold to the case of arbitrary magnetic field.

  20. Short rotation woody crops: Using agroforestry technology for energy in the United States

    SciTech Connect

    Wright, L L; Ranney, J W

    1991-01-01

    Agroforestry in the United States is being primarily defined as the process of using trees in agricultural systems for conservation purposes and multiple products. The type of agroforestry most commonly practiced in many parts of the world, that is the planting of tree crops in combination with food crops or pasture, is the type least commonly practiced in the United States. One type of agroforestry technique, which is beginning now and anticipated to expand to several million acres in the United States, is the planting of short-rotation woody crops (SRWCs) primarily to provide fiber and fuel. Research on SRWC's and environmental concerns are described.

  1. Rotational State Microwave Mixing for Laser Cooling of Complex Diatomic Molecules

    NASA Astrophysics Data System (ADS)

    Yeo, Mark; Hummon, Matthew T.; Collopy, Alejandra L.; Yan, Bo; Hemmerling, Boerge; Chae, Eunmi; Doyle, John M.; Ye, Jun

    2015-06-01

    We demonstrate the mixing of rotational states in the ground electronic state using microwave radiation to enhance optical cycling in the molecule yttrium (II) monoxide (YO). This mixing technique is used in conjunction with a frequency modulated and chirped continuous wave laser to slow longitudinally a cryogenic buffer-gas beam of YO. We generate a flux of YO below 10 m /s , directly loadable into a three-dimensional magneto-optical trap. This technique opens the door for laser cooling of diatomic molecules with more complex loss channels due to intermediate states.

  2. Infrared Spectroscopy of Ions in Selected Rotational and Spin-Orbit States

    NASA Astrophysics Data System (ADS)

    Jacovella, Ugo; Agner, Josef A.; Schmutz, Hansjürg; Merkt, Frederic

    2016-06-01

    First results are presented obtained using an experimental setup developed to record IR spectra of rotationally state-selected ions. The method we use is a state-selective version of a method developed by Schlemmer et al. to record IR spectra of ions. Ions are produced in specific rotational levels using mass-analysed threshold ionisation (MATI) spectroscopy combined with single-photon excitation of neutral molecules in supersonic expansions with a vacuum-ultraviolet laser. The ions generated by pulsed-field ionisation of Rydberg states of high principal quantum number (n ≈ 200) are extracted toward an octupole ion guide containing a neutral target gas. Prior to entering the octupole the ions are excited by an IR laser. The target gas is chosen so that only excited ions react to form product ions. These product ions are detected mass selectively as function of the IR laser wavenumber. To illustrate this method, we present IR spectra of C_2H_2^+ in selected rotational levels of the ^2Π3/2 and ^2Π1/2 spin-orbit components of the electronic ground state. Schlemmer et al., J. Chem. Phys. 117, 2068 (2002)

  3. Enhanced optical cycling and slowing of YO through rotational state microwave mixing

    NASA Astrophysics Data System (ADS)

    Yan, Bo; Hummon, Matthew; Yeo, Mark; Collopy, Alejandra; Hemmerling, Boerge; Chae, Eunmi; Anderegg, Loic; Ravi, Aakash; Doyle, John; Ye, Jun

    2015-05-01

    In order to address rotational dark states in the molecule yttrium (II) monoxide (YO) and to enhance optical cycling, we demonstrate the remixing of ground electronic state rotational levels using microwave radiation. This mixing technique, in conjunction with a broadband modulated and frequency chirped laser, is used to decelerate a beam of YO from a cryogenic buffer gas cell. The result is a population of molecules with velocities less than 10 m/s, which are sufficiently slow to be loaded into a magneto-optical trap. With two vibrational repump lasers, the cycling transition is closed to the 10-6 level. Additionally, we present progress towards a three dimensional implementation of a magneto-optical trap for YO. This work was supported in part by the Gordon and Betty Moore Foundation through Grant GBMF3852. We also acknowledge support from ARO, AFOSR (MURI), NIST, and NSF.

  4. Rotational spectra of isotopic species of methyl cyanide, CH3CN, in their v8 = 1 excited vibrational states

    NASA Astrophysics Data System (ADS)

    Müller, Holger S. P.; Drouin, Brian J.; Pearson, John C.; Ordu, Matthias H.; Wehres, Nadine; Lewen, Frank

    2016-02-01

    Context. Methyl cyanide is an important trace molecule in space, especially in star-forming regions where it is one of the more common molecules used to derive kinetic temperatures. Aims: We want to obtain accurate spectroscopic parameters of minor isotopologs of methyl cyanide in their lowest excited ν8 = 1 vibrational states to support astronomical observations, in particular, with interferometers such as ALMA. Methods: The laboratory rotational spectrum of methyl cyanide in natural isotopic composition has been recorded from the millimeter to the terahertz regions. Results: Transitions with good signal-to-noise ratios could be identified for the three isotopic species CH313CN, 13CH3CN, and CH3C15N up to about 1.2 THz (J'' ≤ 66). Accurate spectroscopic parameters were obtained for all three species. Conclusions: The present data were already instrumental in identifying ν8 = 1 lines of methyl cyanide with one 13C in IRAM 30 m and ALMA data toward Sagittarius B2(N).

  5. Global Properties of Rotating Neutron Stars with QCD Equations of State

    NASA Astrophysics Data System (ADS)

    Gorda, Tyler

    2016-11-01

    We numerically investigate global properties of rotating neutron stars (NSs) using the allowed band of QCD equations of state derived by Kurkela et al. This band is constrained by chiral effective theory at low densities and perturbative QCD at high densities, and is thus, in essence, a controlled constraint from first-principles physics. Previously, this band of equations of state was used to investigate non-rotating NSs only; in this work, we extend these results to any rotation frequency below the mass-shedding limit. We investigate mass–radius curves, allowed mass–frequency regions, radius–frequency curves for a typical 1.4{M}ȯ star, and the values of the moment of inertia of the double pulsar PSR J0737-3039A, a pulsar for which the moment of inertia may be constrained observationally in a few years. We present limits on observational data coming from these constraints, and identify values of observationally relevant parameters that would further constrain the allowed region for the QCD equation of state. We also discuss how much this region would be constrained by a measurement of the moment of inertia of the double pulsar PSR J0737-3039A.

  6. Symmetry Beyond Perturbation Theory: Floppy Molecules and Rotation-Vibration States

    NASA Astrophysics Data System (ADS)

    Schmiedt, Hanno; Schlemmer, Stephan; Jensen, Per

    2015-06-01

    In the customary approach to the theoretical description of the nuclear motion in molecules, the molecule is seen as a near-static structure rotating in space. Vibrational motion causing small structural deformations induces a perturbative treatment of the rotation-vibration interaction, which fails in fluxional molecules, where all vibrational motions are large compared to the linear extension of the molecule. An example is protonated methane (CH_5^+). For this molecule, customary theory fails to simulate reliably even the low-energy spectrum. Within the traditional view of rotation and vibration being near-separable, rotational and vibrational wavefunctions can be symmetry classified separately in the molecular symmetry (MS) group. In the present contribution we discuss a fundamental group theoretical approach to the problem of determining the symmetries of molecular rotation-vibration states. We will show that all MS groups discussed so far are subgroups of the special orthogonal group in three dimensions SO(3) This leads to a group theoretical foundation of the technique of equivalent rotations. The MS group of protonated methane (G240) represents, to the best of our knowledge, the first example of an MS group which is not a subgroup of SO(3) (nor of O(3) nor of SU(2)). Because of this, a separate symmetry classification of vibrational and rotational wavefunctions becomes impossible in this MS group, consistent with the fact that a decoupling of vibrational and rotational motion is impossible. We want to discuss the consequences of this. In conclusion, we show that the prototypical floppy molecule CH_5^+ represents a new class of molecules, where usual group theoretical methods for determining selection rules and spectral assignments fail so that new methods have to be developed. P. Kumar and D. Marx, Physical Chemistry Chemical Physics 8, 573 (2006) Z. Jin, B. J. Braams, and J. M. Bowman, The Journal of Physical Chemistry A 110, 1569 (2006) A. S. Petit, J. E

  7. Symmetry of extremely floppy molecules: Molecular states beyond rotation-vibration separation

    NASA Astrophysics Data System (ADS)

    Schmiedt, Hanno; Schlemmer, Stephan; Jensen, Per

    2015-10-01

    Traditionally, molecules are theoretically described as near-static structures rotating in space. Vibrational motion causing small structural deformations induces a perturbative treatment of the rotation-vibration interaction, which fails in highly fluxional molecules, where all vibrational motions have amplitudes comparable in size to the linear dimensions of the molecule. An example is protonated methane (CH 5+ ) [P. Kumar and D. Marx, Phys. Chem. Chem. Phys. 8, 573 (2006); Z. Jin et al., J. Phys. Chem. A 110, 1569 (2006); and A. S. Petit et al., J. Phys. Chem. A 118, 7206 (2014)]. For these molecules, customary theory fails to simulate reliably even the low-energy spectrum [T. Oka, Science 347, 1313-1314 (2015) and O. Asvany et al., Science 347, 1346-1349 (2015)]. Within the traditional view of rotation and vibration being near-separable, rotational and vibrational wavefunctions can be symmetry classified separately in the molecular symmetry (MS) group [P. Bunker and P. Jensen, Molecular Symmetry and Spectroscopy, NRC Monograph Publishing Program (NRC Research Press, 2006)]. In this article, we discuss a fundamental group theoretical approach to the problem of determining the symmetries of molecular rotation-vibration states. We will show that all MS groups discussed so far are isomorphic to subgroups of the special orthogonal group in three dimensions SO(3). This leads to a group theoretical foundation of the technique of equivalent rotations [H. Longuet-Higgins, Mol. Phys. 6, 445 (1963)]. The group G240 (the MS group of protonated methane) represents, to the best of our knowledge, the first example of a MS group which is not isomorphic to a subgroup of SO(3) (nor of O(3) or of SU(2)). Because of this, a separate symmetry classification of vibrational and rotational wavefunctions becomes impossible in this MS group, consistent with the fact that a decoupling of vibrational and rotational motion is impossible. We discuss here the consequences of this. In

  8. Toward Rotational State-Selective Photoionization of ThF+ Ions

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Ng, Kia Boon; Gresh, Dan; Cairncross, William; Grau, Matt; Ni, Yiqi; Cornell, Eric; Ye, Jun

    2016-06-01

    ThF+ has been chosen to replace HfF+ for a second-generation measurement of the electric dipole moment of the electron (eEDM). Compared to the currently running HfF+ eEDM experiment, ThF+ has several advantages: (i) the eEDM-sensitive state (3Δ1) is the ground state, which facilitates a long coherence time [1]; (ii) its effective electric field (35 GV/cm) is 50% larger than that of HfF+, which promises a direct increase of the eEDM sensitivity [2]; and (iii) the ionization energy of neutral ThF is lower than its dissociation energy, which introduces greater flexibility in rotational state-selective photoionization via core-nonpenetrating Rydberg states [3]. In this talk, we first present our strategy of preparing and utilizing core-nonpenetrating Rydberg states for rotational state-selective ionization. Then, we report spectroscopic data of laser-induced fluorescence of neutral ThF, which provides critical information for multi-photon ionization spectroscopy. [1] D. N. Gresh, K. C. Cossel, Y. Zhou, J. Ye, E. A. Cornell, Journal of Molecular Spectroscopy, 319 (2016), 1-9 [2] M. Denis, M. S. Nørby, H. J. A. Jensen, A. S. P. Gomes, M. K. Nayak, S. Knecht, T. Fleig, New Journal of Physics, 17 (2015) 043005. [3] Z. J. Jakubek, R. W. Field, Journal of Molecular Spectroscopy 205 (2001) 197-220.

  9. Probabilistic rotational state preparation of a single molecular ion though consecutive partial projection measurements

    NASA Astrophysics Data System (ADS)

    Drewsen, Michael

    2016-05-01

    Fully quantum state prepared molecular ions are of interest for a wide range of research fields, including ultra-cold chemistry, ultra-high resolution spectroscopy for test of fundamental physics, and quantum information science. Cooling of the translational degrees of freedom of trapped molecular ions into the millikelvin range has become routine through Coulomb interactions with simultaneously trapped and Doppler laser-cooled atomic ions, and recently it has even become possible to prepare a single molecular ion in its absolute ground state with respect to its quantized motion in the external trapping potential. With respect to the internal rovibrational degrees of freedom, significant progress towards single quantum state preparation has as well recently been realized by a series of complementary methods. In the talk, a novel method for probabilistic rotational state preparation of polar molecular ions based on consecutive partial projection measurements will be discussed. Results of state preparation of vibrational cold single MgH+ ions in the rotational ground or first excited state with maximum likelihood estimated populations of 0.98 and 0.95, respectively, will be presented.

  10. Design of tailored microwave pulses to create rotational coherent states for an asymmetric-top molecule

    NASA Astrophysics Data System (ADS)

    Ortigoso, Juan

    1998-06-01

    Tailored microwave pulses, to guide asymmetric-top molecules from selected rotational states belonging to the vibronic ground state to generalized angular-momentum coherent states, are designed by using optimal control theory. Characteristics that the molecules have to fulfill in order to achieve the goal with feasible pulses are discussed. Properties of the pulses are discussed as well. The further dephasing among the components of the wave packet which, for the simplest coherent state, is a form of dynamical tunneling, can be locked by exploiting the changes that energy levels and eigenfunctions undergo in the presence of an external static electric field with appropriate intensity. For the special case with M=0, periodic fields are more flexible in avoiding dephasing. This is shown by examining properties of quasienergies and dressed states resulting from the diagonalization of a truncated Floquet matrix.

  11. Coherent libration to coherent rotational dynamics via chimeralike states and clustering in a Josephson junction array

    NASA Astrophysics Data System (ADS)

    Mishra, Arindam; Saha, Suman; Hens, Chittaranjan; Roy, Prodyot K.; Bose, Mridul; Louodop, Patrick; Cerdeira, Hilda A.; Dana, Syamal K.

    2017-01-01

    An array of excitable Josephson junctions under a global mean-field interaction and a common periodic forcing shows the emergence of two important classes of coherent dynamics, librational and rotational motion, in the weaker and stronger coupling limits, respectively, with transitions to chimeralike states and clustered states in the intermediate coupling range. In this numerical study, we use the Kuramoto complex order parameter and introduce two measures, a libration index and a clustering index, to characterize the dynamical regimes and their transitions and locate them in a parameter plane.

  12. Rotational Spectrum of SO_3 and Theoretical Evidence for the Formation of Rotational Energy Level Clusters in its Vibrational Ground State

    NASA Astrophysics Data System (ADS)

    Underwood, Daniel S.; Yurchenko, Sergei N.; Tennyson, Jonathan; Jensen, Per

    2014-06-01

    The structure of the purely rotational spectrum of sulphur trioxide SO_3 is investigated using a new synthetic line list. The list combines line positions from an empirical model with line intensities determined, in the form of Einstein coefficients, from variationally computed ro-vibrational wavefunctions in conjunction with an ab initio dipole moment surface. The empirical model providing the line positions involves an effective, Watsonian-type rotational Hamiltonian with literature parameter values resulting from least-squares fittings to observed transition frequencies. The formation of so-called rotational energy clusters at high rotational excitation are investigated. The SO_3 molecule is planar at equilibrium and exhibits a unique type of rotational-energy clustering associated with unusual stabilization axes perpendicular to the S--O bonds. This behaviour is characterized theoretically in the J range from 100 through 250. The wavefunctions for these cluster states are analysed, and the results are compared to those of a classical analysis in terms of the rotational-energy-surface formalism.

  13. Using Diffusion Monte Carlo to Probe the Rotationally Excited States of H_3^+ and its Isotopologues

    NASA Astrophysics Data System (ADS)

    Wellen, Bethany A.; Petit, Andrew S.; McCoy, Anne B.

    2011-06-01

    H3-ND_n^+ are among the most abundant polyatomic ions in the universe. Moreover, the deuterated isotopologues are thought to play a key role in the astrochemical reactions governing the H/D fractionation of "metallic" species in the interstellar medium. An accurate quantum mechanical treatment of these species, as well as any reactions involving them, requires a methodology capable of capturing their large fluxionality as well as the constraints, due to particle exchange symmetries, on their physically allowed rovibrational states. Diffusion Monte Carlo (DMC) has been shown to be a highly successful technique for treating quantum zero-point effects of very floppy molecules and clusters and our group has recently developed a fixed-node DMC methodology capable of including the effects of rotational excitation. Here, we report the results of DMC calculations of the rotationally excited states of H_3^+ and its isotopologues. In particular, comparison with converged variational calculations involving states with J ≤ 20 provides the most thorough test yet of the range of quantum states over which the assumptions underlying our rotationally excited state DMC methodology can be reliably applied. Finally, the implications of this work on our overall goal of using DMC based methodologies to map out the energetics of the reaction of H3-ND_n^+ with HD will be discussed. T. R. Geballe and T. Oka, Science 312, 1610 (2006) E. Hugo, O. Asvany, and S. Schlemmer, J. Chem. Phys. 130, 164302 (2009) A. S. Petit and A. B. McCoy, J. Phys. Chem. A 113, 12706 (2009)

  14. Steady-State Computation of Constant Rotational Rate Dynamic Stability Derivatives

    NASA Technical Reports Server (NTRS)

    Park, Michael A.; Green, Lawrence L.

    2000-01-01

    Dynamic stability derivatives are essential to predicting the open and closed loop performance, stability, and controllability of aircraft. Computational determination of constant-rate dynamic stability derivatives (derivatives of aircraft forces and moments with respect to constant rotational rates) is currently performed indirectly with finite differencing of multiple time-accurate computational fluid dynamics solutions. Typical time-accurate solutions require excessive amounts of computational time to complete. Formulating Navier-Stokes (N-S) equations in a rotating noninertial reference frame and applying an automatic differentiation tool to the modified code has the potential for directly computing these derivatives with a single, much faster steady-state calculation. The ability to rapidly determine static and dynamic stability derivatives by computational methods can benefit multidisciplinary design methodologies and reduce dependency on wind tunnel measurements. The CFL3D thin-layer N-S computational fluid dynamics code was modified for this study to allow calculations on complex three-dimensional configurations with constant rotation rate components in all three axes. These CFL3D modifications also have direct application to rotorcraft and turbomachinery analyses. The modified CFL3D steady-state calculation is a new capability that showed excellent agreement with results calculated by a similar formulation. The application of automatic differentiation to CFL3D allows the static stability and body-axis rate derivatives to be calculated quickly and exactly.

  15. Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state

    NASA Astrophysics Data System (ADS)

    Okada, Ken N.; Takahashi, Youtarou; Mogi, Masataka; Yoshimi, Ryutaro; Tsukazaki, Atsushi; Takahashi, Kei S.; Ogawa, Naoki; Kawasaki, Masashi; Tokura, Yoshinori

    2016-07-01

    Electrodynamic responses from three-dimensional topological insulators are characterized by the universal magnetoelectric term constituent of the Lagrangian formalism. The quantized magnetoelectric coupling, which is generally referred to as topological magnetoelectric effect, has been predicted to induce exotic phenomena including the universal low-energy magneto-optical effects. Here we report the experimental indication of the topological magnetoelectric effect, which is exemplified by magneto-optical Faraday and Kerr rotations in the quantum anomalous Hall states of magnetic topological insulator surfaces by terahertz magneto-optics. The universal relation composed of the observed Faraday and Kerr rotation angles but not of any material parameters (for example, dielectric constant and magnetic susceptibility) well exhibits the trajectory towards the fine structure constant in the quantized limit.

  16. Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state

    PubMed Central

    Okada, Ken N.; Takahashi, Youtarou; Mogi, Masataka; Yoshimi, Ryutaro; Tsukazaki, Atsushi; Takahashi, Kei S.; Ogawa, Naoki; Kawasaki, Masashi; Tokura, Yoshinori

    2016-01-01

    Electrodynamic responses from three-dimensional topological insulators are characterized by the universal magnetoelectric term constituent of the Lagrangian formalism. The quantized magnetoelectric coupling, which is generally referred to as topological magnetoelectric effect, has been predicted to induce exotic phenomena including the universal low-energy magneto-optical effects. Here we report the experimental indication of the topological magnetoelectric effect, which is exemplified by magneto-optical Faraday and Kerr rotations in the quantum anomalous Hall states of magnetic topological insulator surfaces by terahertz magneto-optics. The universal relation composed of the observed Faraday and Kerr rotation angles but not of any material parameters (for example, dielectric constant and magnetic susceptibility) well exhibits the trajectory towards the fine structure constant in the quantized limit. PMID:27436710

  17. Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state.

    PubMed

    Okada, Ken N; Takahashi, Youtarou; Mogi, Masataka; Yoshimi, Ryutaro; Tsukazaki, Atsushi; Takahashi, Kei S; Ogawa, Naoki; Kawasaki, Masashi; Tokura, Yoshinori

    2016-07-20

    Electrodynamic responses from three-dimensional topological insulators are characterized by the universal magnetoelectric term constituent of the Lagrangian formalism. The quantized magnetoelectric coupling, which is generally referred to as topological magnetoelectric effect, has been predicted to induce exotic phenomena including the universal low-energy magneto-optical effects. Here we report the experimental indication of the topological magnetoelectric effect, which is exemplified by magneto-optical Faraday and Kerr rotations in the quantum anomalous Hall states of magnetic topological insulator surfaces by terahertz magneto-optics. The universal relation composed of the observed Faraday and Kerr rotation angles but not of any material parameters (for example, dielectric constant and magnetic susceptibility) well exhibits the trajectory towards the fine structure constant in the quantized limit.

  18. Quantum non-equilibrium effects in rigidly-rotating thermal states

    NASA Astrophysics Data System (ADS)

    Ambruş, Victor E.

    2017-08-01

    Based on known analytic results, the thermal expectation value of the stress-energy tensor (SET) operator for the massless Dirac field is analysed from a hydrodynamic perspective. Key to this analysis is the Landau decomposition of the SET, with the aid of which we find terms which are not present in the ideal SET predicted by kinetic theory. Moreover, the quantum corrections become dominant in the vicinity of the speed of light surface (SOL). While rigidly-rotating thermal states cannot be constructed for the Klein-Gordon field, we perform a similar analysis at the level of quantum corrections previously reported in the literature and we show that the Landau frame is well-defined only when the system is enclosed inside a boundary located inside or on the SOL. We discuss the relevance of these results for accretion disks around rapidly-rotating pulsars.

  19. New clues on the interior of Titan from its rotation state

    NASA Astrophysics Data System (ADS)

    Noyelles, Benoît; Nimmo, Francis

    2014-07-01

    The Saturnian satellite Titan is one of the main targets of the Cassini-Huygens mission, which revealed in particular Titan's shape, gravity field, and rotation state. The shape and gravity field suggest that Titan is not in hydrostatic equilibrium, that it has a global subsurface ocean, and that its ice shell is both rigid (at tidal periods) and of variable thickness. The rotational state of Titan consists of an expected synchronous rotation rate and an unexpectedly high obliquity (0.3○) explained by Baland et al. (2011) to be a resonant behavior. We here combine a realistic model of the ice shell and interior and a 6-degrees of freedom rotational model, in which the librations, obliquity and polar motion of the rigid core and of the shell are modelled, to constrain the structure of Titan from the observations. We consider the gravitational pull of Saturn on the 2 rigid layers, the gravitational coupling between them, and the pressure coupling at the liquid-solid interfaces. We confirm the influence of the resonance found by Baland et al., that affects between 10 and 13% of the possible Titans. It is due to the 29.5-year periodic annual forcing. The resonant Titans can be obtained in situations in which a mass anomaly at the shell-ocean boundary (bottom loading) is from 80 to 92% compensated. This suggests a 250 to 280 km thick ocean below a 130 to 140 km thick shell, and is consistent with the degree-3 analysis of Hemingway 26 et al. (2013).

  20. Rotational Spectrum of Sarin

    NASA Astrophysics Data System (ADS)

    Walker, A. R. Hight; Suenram, R. D.; Samuels, Alan; Jensen, James; Ellzy, Michael W.; Lochner, J. Michael; Zeroka, Daniel

    2001-05-01

    As part of an effort to examine the possibility of using molecular-beam Fourier-transform microwave spectroscopy to unambiguously detect and monitor chemical warfare agents, we report the first observation and assignment of the rotational spectrum of the nerve agent Sarin (GB) (Methylphosphonofluoridic acid 1-methyl-ethyl ester, CAS #107-44-8) at frequencies between 10 and 22 GHz. Only one of the two low-energy conformers of this organophosphorus compound (C4H10FO2P) was observed in the rotationally cold (Trot<2 K) molecular beam. The experimental asymmetric-rotor ground-state rotational constants of this conformer are A=2874.0710(9) MHz, B=1168.5776(4) MHz, C=1056.3363(4) MHz (Type A standard uncertainties are given, i.e., 1σ), as obtained from a least-squares analysis of 74 a-, b-, and c-type rotational transitions. Several of the transitions are split into doublets due to the internal rotation of the methyl group attached to the phosphorus. The three-fold-symmetry barrier to internal rotation estimated from these splittings is 677.0(4) cm-1. Ab initio electronic structure calculations using Hartree-Fock, density functional, and Moller-Plesset perturbation theories have also been made. The structure of the lowest-energy conformer determined from a structural optimization at the MP2/6-311G** level of theory is consistent with our experimental findings.

  1. W∞-ALGEBRA for Fermions in the Lowest Landau Level

    NASA Astrophysics Data System (ADS)

    Myung, Yun Soo

    We derive the W∞-algebra directly from the cocycle (translational) transformation of fermions in the lowest Landau level. This happens whenever the translational symmetry is unbroken in the ground state. Under the cocycle transformations, the lowest Landau level condition and fermion number are preserved. In the droplet approximation, the algebra of this system is reduced to the classical w∞-algebra (area-preserving deformations) and is related to condensed matter physics. This describes the edge modes of the fractional quantum Hall effect.

  2. Calculation of Ground State Rotational Populations for Kinetic Gas Homonuclear Diatomic Molecules including Electron-Impact Excitation and Wall Collisions

    SciTech Connect

    David R. Farley

    2010-08-19

    A model has been developed to calculate the ground-state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with non-equilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.

  3. Spectroscopic analysis of transition state energy levels - Bending-rotational spectrum and lifetime analysis of H3 quasibound states

    NASA Technical Reports Server (NTRS)

    Zhao, Meishan; Mladenovic, Mirjana; Truhlar, Donald G.; Schwenke, David W.; Sharafeddin, Omar

    1989-01-01

    Converged quantum mechanical calculations of scattering matrices and transition probabilities are reported for the reaction of H with H2 with total angular momentum 0, 1, and 4 as functions of total energy in the range 0.85-1.15 eV on an accurate potential energy surface. The resonance structure is illustrated with Argand diagrams. State-to-state reactive collision delay times and lifetimes are presented. For J = 0, 1, and 4, the lowest-energy H3 resonance is at total energies of 0.983, 0.985, and 1.01 eV, respectively, with lifetimes of about 16-17 fs. For J = 1 and 4 there is a higher-energy resonance at 1.10-1.11 eV. For J = 1 the lifetime is about 4 fs and for J = 4 it is about 1 fs.

  4. Transition from vibrational to rotational character in low-lying states of hypernuclei

    NASA Astrophysics Data System (ADS)

    Mei, H.; Hagino, K.; Yao, J. M.; Motoba, T.

    2017-07-01

    In order to clarify the nature of hypernuclear low-lying states, we carry out a comprehensive study of the structure of Λ 145-155Sm hypernuclei, which exhibit a transition from vibrational to rotational character as the neutron number increases. To this end, we employ a microscopic particle-core coupling scheme based on a covariant density functional theory. We find that the positive-parity ground-state band in the hypernuclei shares a similar structure to that of the corresponding core nucleus. That is, regardless of whether the core nucleus is spherical or deformed, each hypernuclear state is dominated by the single configuration of the Λ particle in the s1 /2 state (Λ s1 /2 ) coupled to one core state of the ground band. In contrast, the low-lying negative-parity states mainly consist of Λ p1 /2 and Λ p3 /2 configurations coupled to plural nuclear core states. We show that, while the mixing amplitude between these configurations is negligibly small in spherical and weakly deformed nuclei, it strongly increases as the core nucleus undergoes a transition to a well deformed shape, which is consistent with the Nilsson wave functions. We demonstrate that the structure of these negative-parity states with spin I can be well understood based on a naive L S coupling scheme, with total orbital angular momentum L =[I ⊗1 ] and spin angular momentum S =1 /2 .

  5. Lowest Landau level diamagnetic fluctuations in niobium

    NASA Astrophysics Data System (ADS)

    Salem-Sugui, Said; Friesen, M.; Alvarenga, A. D.; Schilling, Osvaldo F.; Gandra, F. G.; Doria, M. M.

    2004-08-01

    We have performed a magnetic study of a bulk metallic sample of Nb with critical temperature Tc = 8.5 K. Magnetization measurements taken for magnetic fields greater than 1 kOe show a superconducting transition that becomes broader as the field is increased. The data are well described by lowest Landau level (LLL) fluctuation theory. A scaling analysis yields values for the superconducting transition temperature under field Tc( H) which are consistent with Hc2( T).

  6. Quantum state tomography for quadrupolar nuclei using global rotations of the spin system.

    PubMed

    Teles, J; deAzevedo, E R; Auccaise, R; Sarthour, R S; Oliveira, I S; Bonagamba, T J

    2007-04-21

    In this paper, we describe a quantum state tomography method based on global rotations of the spin system which, together with a coherence selection scheme, enables the complete density matrix reconstruction. The main advantage of this technique, in respect to previous proposals, is the use of much shorter rf pulses, which decreases significantly the time necessary for algorithm quantum state tomography. In this case, under adequate experimental conditions, the rf pulses correspond to simple spatial rotations of the spin states, and its analytical description is conveniently given in the irreducible tensor formalism. Simulated results show the feasibility of the method for a single spin 72 nucleus. As an experimental result, we exemplify the application of this method by tomographing the steps during the implementation of the Deutsch algorithm. The algorithm was implemented in a (23)Na quadrupole nucleus using the strongly modulated pulses technique. We also extended the tomography method for a 3-coupled homonuclear spin 12 system, where an additional evolution under the internal Hamiltonian is necessary for zero order coherences evaluation.

  7. Rotational 2+ states of superheavy elements in the Skyrme-Hartree-Fock-Bogoliubov model

    NASA Astrophysics Data System (ADS)

    Baran, A.; Staszczak, A.

    2013-05-01

    The Skyrme-Hartree-Fock-Bogoliubov calculations of the energies of first 2+ rotational states of deformed superheavy (SH) elements in the region of 108 ⩽ Z ⩽ 126 and 148 ⩽ N ⩽ 180 are reported. The results agree well in the case of fermium isotopes after a proper scaling of the moment of inertia. The scaling factor equals 1.3. The extension of the model to the region of SH elements gives a possibility of better estimation of the Q-values of α-decay, which is a dominant decay mode of SH elements.

  8. Terahertz rotational spectra of NH 2OH in the ground and some low excited vibrational states

    NASA Astrophysics Data System (ADS)

    Morino, I.; Yamada, K. M. T.; Klein, H.; Belov, S. P.; Winnewisser, G.; Bocquet, R.; Wlodarczak, G.; Lodyga, W.; Kreglewski, M.

    2000-02-01

    The rotational spectra of hydroxylamine, NH2OH, have been measured for the ground and some excited vibrational states, with high precision in the mmW (millimeter wave) and sub-mmW region, up to 1.8 THz, using BWO based spectrometers and a laser-side-band FIR spectrometer. No tunnel splitting has been observed and it is concluded that the barrier to the tunneling motion is very high. The observed line positions have been analyzed with Watson's S-reduced Hamiltonian with extension to higher order terms up to J10 order.

  9. Synchrotron far-infrared spectroscopy of the two lowest fundamental modes of 1,1-difluoroethane

    NASA Astrophysics Data System (ADS)

    Wong, Andy; Thompson, Christopher D.; Appadoo, Dominique R. T.; Plathe, Ruth; Roy, Pascale; Manceron, Laurent; Barros, Joanna; McNaughton, Don

    2013-08-01

    The far-infrared (FIR) spectrum (50-600 cm-1) of 1,1-difluoroethane was recorded using the high-resolution infrared AILES beamline at the Soleil synchrotron. A ro-vibrational assignment was performed on the lowest wavenumber, low intensity 181 0 and 171 0 modes, yielding band centres of 224.241903 (10) cm-1 and 384.252538 (13) cm-1, respectively. A total of 965 and 2031 FIR transitions were assigned to the 181 0 and 171 0 fundamentals, respectively. Previously measured pure rotational transitions from the upper states were included into the respective fits to yield improved rotational and centrifugal distortion constants. The 182 1 hot band was observed within the fundamental band, with 369 FIR transitions assigned and co-fitted with the fundamental to give a band centre of 431.956502 (39) cm-1 for ν 18 = 2. The 182 0 overtone was observed with 586 transitions assigned and fitted to give a band centre of 431.952763 (23) cm-1 for ν 18 = 2. The difference in energy is attributed to a torsional splitting of 0.003740 (45) cm-1 in the ν 18 = 2 state. Two hot bands originating from the ν 18 = 1 and ν 17 = 1 states were observed within the 171 0 fundamental.

  10. Intercept-resend attack on six-state quantum key distribution over collective-rotation noise channels

    NASA Astrophysics Data System (ADS)

    Kevin, Garapo; Mhlambululi, Mafu; Francesco, Petruccione

    2016-07-01

    We investigate the effect of collective-rotation noise on the security of the six-state quantum key distribution. We study the case where the eavesdropper, Eve, performs an intercept-resend attack on the quantum communication between Alice, the sender, and Bob, the receiver. We first derive the collective-rotation noise model for the six-state protocol and then parameterize the mutual information between Alice and Eve. We then derive quantum bit error rate for three intercept-resend attack scenarios. We observe that the six-state protocol is robust against intercept-resend attacks on collective rotation noise channels when the rotation angle is kept within certain bounds. Project supported by the South African Research Chair Initiative of the Department of Science and Technology and National Research Foundation.

  11. Submillimeter-wave rotational spectra of DNC in highly excited vibrational states observed in an extended negative glow discharge

    NASA Astrophysics Data System (ADS)

    Amano, T.

    2011-05-01

    Rotational transitions of DNC have been observed in the submillimeter-wave region in an extended negative glow discharge in a gas mixture of CD 4 and N 2. The dissociative recombination reaction of DCND + with electrons is thought to be a dominant channel to produce DNC in highly excited vibrational states. The vibrational temperature for the ν3 vibrational mode is found to be about 4000 K, and the rotational lines in levels up to (0 0 8) are observed. The rotational and centrifugal distortion constants are determined for these states along with those for the (1 0 0) state. The measurement accuracy is high enough to determine some higher order vibration-rotation interaction constants.

  12. The electronic spectrum of AgCl2: Ab initio benchmark versus density-functional theory calculations on the lowest ligand-field states including spin-orbit effects

    NASA Astrophysics Data System (ADS)

    Ramírez-Solís, A.; Poteau, R.; Daudey, J. P.

    2006-01-01

    The XΠg2, Σg+2, and Δg2 states of AgCl2 have been studied through benchmark ab initio complete active space self-consistent field plus second-order complete active space multireference Möller-Plesset algorithm (CASSCF +CASPT2) and complete active space self-consistent field plus averaged coupled pair functional (CASSCF +ACPF) and density-functional theory (DFT) calculations using especially developed basis sets to study the transition energies, geometries, vibrational frequencies, Mulliken charges, and spin densities. The spin-orbit (SO) effects were included through the effective Hamiltonian formalism using the ΛSΣ ACPF energies as diagonal elements. At the ACPF level, the ground state is Πg2 in contradiction with ligand-field theory, SCF, and large CASSCF; the adiabatic excitation energies for the Σg+2 and Δg2 states are 1640 and 18230cm-1, respectively. The inclusion of the SO effects leads to a pure Ω =3/2(Πg2) ground state, a Ω =1/2 (66%Πg2 and 34%Σg+2) A state, a Ω =1/2 (34%Πg2 and 66%Σg+2) B state, a Ω =5/2(Δg2)C state, and a Ω =3/2(99%Δg2)D state. The X-A, X-B, X-C, and X-D transition energies are 485, 3715, 17 246, and 20110cm-1, respectively. The B97-2, B3LYP, and PBE0 functionals overestimate by ≈100% the XΠg2-Σg+2Te but provide a qualitative energetic ordering in good agreement with ACPF results. B3LYP with variable exchange leads to a 42% optimal Hartree-Fock exchange for transition energies but all equilibrium geometries get worsened. Asymptotic corrections to B3LYP do not provide improved values. The nature of the bonding in the XΠg2 state is very different from that of CuCl2 since the Mulliken charge on the metal is 1.1 while the spin density is only 0.35. DFT strongly delocalizes the spin density providing even smaller values of around 0.18 on Ag not only for the ground state, but also for the Σg+2 state.

  13. The lowest Landau level in QCD

    NASA Astrophysics Data System (ADS)

    Bruckmann, Falk; Endrőodi, Gergely; Giordano, Matteo; Katz, Sándor D.; Kovács, Tamás G.; Pittler, Ferenc; Wellnhofer, Jacob

    2017-03-01

    The thermodynamics of Quantum Chromodynamics (QCD) in external (electro-)magnetic fields shows some unexpected features like inverse magnetic catalysis, which have been revealed mainly through lattice studies. Many effective descriptions, on the other hand, use Landau levels or approximate the system by just the lowest Landau level (LLL). Analyzing lattice configurations we ask whether such a picture is justified. We find the LLL to be separated from the rest by a spectral gap in the two-dimensional Dirac operator and analyze the corresponding LLL signature in four dimensions. We determine to what extent the quark condensate is LLL dominated at strong magnetic fields.

  14. Rotational and neutron-hole states in {sup 43}S via the neutron knockout and fragmentation reactions

    SciTech Connect

    Riley, L. A.; Hosier, K. E.; Adrich, P.; Baugher, T. R.; Bazin, D.; Diget, C. A.; Weisshaar, D.; Brown, B. A.; Cook, J. M.; Gade, A.; Garland, D. A.; Glasmacher, T.; Ratkiewicz, A.; Siwek, K. P.; Cottle, P. D.; Kemper, K. W.; Tostevin, J. A.

    2009-09-15

    The recent assertion that shape coexistence occurs in the neutron-rich isotope {sup 43}S implies that a state observed at 940 keV in a previous study is a rotational excitation of the deformed ground state. Here we use results from two intermediate-energy reactions to demonstrate that this state--assigned an energy of 971 keV in the present work--is indeed a rotational state. This result strengthens the case for shape coexistence in {sup 43}S.

  15. A MCSCF method for ground and excited states based on full optimizations of successive Jacobi rotations.

    PubMed

    Ivanic, Joseph; Ruedenberg, Klaus

    2003-07-30

    A new multiconfigurational self-consistent field (MCSCF) method based on successive optimizations of Jacobi rotation angles is presented. For given one- and two-particle density matrices and an initial set of corresponding integrals, a technique is developed for the determination of a Jacobi angle for the mixing of two orbitals, such that the exact energy, written as a function of the angle, is fully minimized. Determination of the energy-minimizing orbitals for given density matrices is accomplished by successive optimization and updating of Jacobi angles and integrals. The total MCSCF energy is minimized by alternating between CI and orbital optimization steps. Efficiency is realized by optimizing CI and orbital vectors quasi-simultaneously by not fully optimizing each in each improvement step. On the basis of the Jacobi-rotation based approach, a novel MCSCF procedure is formulated for excited states, which avoids certain shortcomings of traditional excited-state MCSCF methods. Applications to specific systems show the practicability of the developed methods.

  16. Effects of Rotational State Excitations on the Dissociative Adsorption Dynamics of D2/Cu(111)

    NASA Astrophysics Data System (ADS)

    Diño, Wilson; Kasai, Hideaki; Okiji, Ayao

    1995-07-01

    Recent time-of-flight experiments show a non-monotonous dependence of the dissociative adsorption/sticking* probability of D2(H2)/Cu(111) on the initial rotational state. There is an observed decrease in the sticking probability with a slight increase in the initial rotational state quantum number j. As j is increased further, the sticking probability eventually increases. We show that, to account for this interesting behaviour, there are two opposing factors working for and against the adsorption process: STEERING EFFECT and ENERGY TRANSFER EFFECT. The first is dueto a dynamical reorientation of the molecule, and the latter is due to the coupling of therotational motion to the translational motion along the reaction path. To illustrate these two effects, we performed quantum mechanical model calculations using a variation of the coupled-channel method, a physically realistic model potential based on available potential energy (hyper-) surface plots for D2(H2)/Cu for two different orientations-parallel and perpendicular to the surface, and the concept of a reaction path.

  17. Rotational state selection and orientation of diatomic and asymmetric top molecules via the electric hexapole technique

    NASA Astrophysics Data System (ADS)

    Hain, Toby Douglas

    2000-11-01

    The hexapole rotational state selection of 2∏ Ω diatomic and asymmetric top molecules is investigated. Classical molecular trajectory simulations are shown to reproduce experimental focusing spectra in these large classes of molecules. Deviations from linear Stark effects introduce significant effects in the focusing behavior of both the 2∏ and asymmetric rotor species. The laboratory frame distributions of orientations of the state-selected molecules are quantified by quantum mechanical orientational probability distribution functions (opdf's). Chapter 1 introduces preliminary data for the hexapole focusing of hydroxyl radicals and shows the deviation of the structured focusing curves from the first-order Stark effect. In Chapter 2, the focusing theory is developed for 2∏ diatomics, and the focusing spectra presented in Chapter 1 are analyzed using the theory. The Λ-doublet splitting is found to be the important parameter for simulating the measured focusing spectra. The high field limit opdf's are calculated, and highly anisotropic orientational distributions for the selected states are shown. Chapter 3 shows the laboratory orientation of 2∏ molecules is tunable via the electric field strength of an orienting field for post- hexapole selected rotational states. A laser induced fluorescence experiment is detailed allowing experimental validation of the theoretical opdf's. Chapter 4 explores the scattering of hexapole selected OD rotational states with various target gases. Elastic scattering cross sections are reported for OD + M (M = He, Ar, H2O, CO2, NH3, and CH3F). Hexapole focusing and the subsequent orientation of asymmetric rotors are the subjects of Chapter 5. Matrix treatments are used to calculate the field-free and Stark energies exactly. Perturbation and intermediate Stark effect approximations are compared to the exact matrix method, yielding several general rules useful in analyzing and predicting experimental focusing spectra. The theory

  18. Stationary State After a Quench to the Lieb-Liniger from Rotating BECs

    NASA Astrophysics Data System (ADS)

    Bucciantini, Leda

    2016-08-01

    We study long-time dynamics of a bosonic system after suddenly switching on repulsive delta-like interactions. As initial states, we consider two experimentally relevant configurations: a rotating BEC and two counter-propagating BECs with opposite momentum, both on a ring. In the first case, the rapidity distribution function for the stationary state is derived analytically and it is given by the distribution obtained for the same quench starting from a BEC, shifted by the momentum of each boson. In the second case, the rapidity distribution function is obtained numerically for generic values of repulsive interaction and initial momentum. The significant differences for the case of large versus small quenches are discussed.

  19. Cryo-EM structures of the autoinhibited E. coli ATP synthase in three rotational states.

    PubMed

    Sobti, Meghna; Smits, Callum; Wong, Andrew Sw; Ishmukhametov, Robert; Stock, Daniela; Sandin, Sara; Stewart, Alastair G

    2016-12-21

    A molecular model that provides a framework for interpreting the wealth of functional information obtained on the E. coli F-ATP synthase has been generated using cryo-electron microscopy. Three different states that relate to rotation of the enzyme were observed, with the central stalk's ε subunit in an extended autoinhibitory conformation in all three states. The Fo motor comprises of seven transmembrane helices and a decameric c-ring and invaginations on either side of the membrane indicate the entry and exit channels for protons. The proton translocating subunit contains near parallel helices inclined by ~30° to the membrane, a feature now synonymous with rotary ATPases. For the first time in this rotary ATPase subtype, the peripheral stalk is resolved over its entire length of the complex, revealing the F1 attachment points and a coiled-coil that bifurcates toward the membrane with its helices separating to embrace subunit a from two sides.

  20. Measurement-Induced State Transitions in a Superconducting Qubit: Beyond the Rotating Wave Approximation

    NASA Astrophysics Data System (ADS)

    Sank, Daniel; Chen, Zijun; Khezri, Mostafa; Kelly, J.; Barends, R.; Campbell, B.; Chen, Y.; Chiaro, B.; Dunsworth, A.; Fowler, A.; Jeffrey, E.; Lucero, E.; Megrant, A.; Mutus, J.; Neeley, M.; Neill, C.; O'Malley, P. J. J.; Quintana, C.; Roushan, P.; Vainsencher, A.; White, T.; Wenner, J.; Korotkov, Alexander N.; Martinis, John M.

    2016-11-01

    Many superconducting qubit systems use the dispersive interaction between the qubit and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce state transitions in the qubit if the number of photons in the resonator is too high. We investigate these transitions and find that they can push the qubit out of the two-level subspace, and that they show resonant behavior as a function of photon number. We develop a theory for these observations based on level crossings within the Jaynes-Cummings ladder, with transitions mediated by terms in the Hamiltonian that are typically ignored by the rotating wave approximation. We find that the most important of these terms comes from an unexpected broken symmetry in the qubit potential. We confirm the theory by measuring the photon occupation of the resonator when transitions occur while varying the detuning between the qubit and resonator.

  1. Blueberry Galaxies: The Lowest Mass Young Starbursts

    NASA Astrophysics Data System (ADS)

    Yang, Huan; Malhotra, Sangeeta; Rhoads, James E.; Wang, Junxian

    2017-09-01

    Searching for extreme emission line galaxies allows us to find low-mass metal-poor galaxies that are good analogs of high redshift Lyα emitting galaxies. These low-mass extreme emission line galaxies are also potential Lyman-continuum leakers. Finding them at very low redshifts (z≲ 0.05) allows us to be sensitive to even lower stellar masses and metallicities. We report on a sample of extreme emission line galaxies at z≲ 0.05 (blueberry galaxies). We selected them from SDSS broadband images on the basis of their broadband colors and studied their properties with MMT spectroscopy. From the entire SDSS DR12 photometric catalog, we found 51 photometric candidates. We spectroscopically confirm 40 as blueberry galaxies. (An additional seven candidates are contaminants, and four remain without spectra.) These blueberries are dwarf starburst galaxies with very small sizes (<1 kpc) and very high ionization ([O iii]/[O ii] ∼ 10–60). They also have some of the lowest stellar masses ({log}(M/{M}ȯ )∼ 6.5{--}7.5) and lowest metallicities (7.1< 12+{log}({{O}}/{{H}})< 7.8) of starburst galaxies. Thus, they are small counterparts to green pea galaxies and high redshift Lyα emitting galaxies.

  2. An experiment on Lowest Unique Integer Games

    NASA Astrophysics Data System (ADS)

    Yamada, Takashi; Hanaki, Nobuyuki

    2016-12-01

    We experimentally study Lowest Unique Integer Games (LUIGs) to determine if and how subjects self-organize into different behavioral classes. In a LUIG, N(≥ 3) players submit a positive integer up to M and the player choosing the smallest number not chosen by anyone else wins. LUIGs are simplified versions of real systems such as Lowest/Highest Unique Bid Auctions that have been attracting attention from scholars, yet experimental studies are scarce. Furthermore, LUIGs offer insights into choice patterns that can shed light on the alleviation of congestion problems. Here, we consider four LUIGs with N = { 3 , 4 } and M = { 3 , 4 } . We find that (a) choices made by more than 1/3 of subjects were not significantly different from what a symmetric mixed-strategy Nash equilibrium (MSE) predicts; however, (b) subjects who behaved significantly differently from what the MSE predicts won the game more frequently. What distinguishes subjects was their tendencies to change their choices following losses.

  3. Is rotating between static and dynamic work beneficial for our fatigue state?

    PubMed

    Luger, Tessy; Bosch, Tim; Hoozemans, Marco J M; Veeger, DirkJan H E J; de Looze, Michiel P

    2016-06-01

    Shoulder disorders comprise a large part of work-related musculoskeletal disorders. Risk factors, such as repetitiveness and monotony, may cause muscle fatigue and be attenuated by task rotation. We investigated rotation between a dynamic box-lifting task and a relatively static pick-and-place task and aimed to determine whether (1) a high rotation frequency leads to less fatigue development than a low rotation frequency, and (2) a self-selected rotation frequency leads to less fatigue development than imposed rotation frequencies. Ten participants performed four one-hour rotation schedules: two low frequency rotation schedules rotating at 30min, one high frequency rotation schedule rotating every sixth minute, and a self-selected rotation schedule. Borg, SOFI and electromyography of Trapezius and Deltoid subparts served as fatigue indicators. We found significant signs of fatigue for most schedules regarding the Borg and SOFI ratings and the M. Trapezius pars Descendens. Task rotation frequency had no significant effect on any of the outcome parameters, whereas the self-selected rotation schedule clearly resulted in less development of perceived fatigue than imposed schedules. In conclusion, we think that freedom of rotation has the greatest potential to attenuate potential development of musculoskeletal disorders and we require due caution with the use and interpretation of EMG indicators of fatigue.

  4. Integrated optical modulator manipulating the polarization and rotation handedness of Orbital Angular Momentum states.

    PubMed

    Mousavi, S Faezeh; Nouroozi, Rahman; Vallone, Giuseppe; Villoresi, Paolo

    2017-06-19

    Recent studies demonstrated that the optical channels encoded by Orbital Angular Momentum (OAM) are capable candidates for improving the next generation of communication systems. OAM states can enhance the capacity and security of high-dimensional communication channels in both classical and quantum regimes based on optical fibre and free space. Hence, fast and precise control of the beams encoded by OAM can provide their commercial applications in the compatible communication networks. Integrated optical devices are good miniaturized options to perform this issue. This paper proposes a numerically verified integrated high-frequency electro-optical modulator for manipulation of the guided modes encoded in both OAM and polarization states. The proposed modulator is designed as an electro-optically active Lithium Niobate (LN) core photonic wire with silica as its cladding in a LN on Insulator (LNOI) configuration. It consists of two successive parts; a phase shifter to reverse the rotation handedness of the input OAM state and a polarization converter to change the horizontally polarized OAM state to the vertically polarized one. It is shown that all four possible output polarization-OAM encoded states can be achieved with only 6 V and 7 V applied voltages to the electrodes in the two parts of the modulator.

  5. Stability of Steady-State Motion of an Isolated System Consisting of a Rotating Body and Two Pendulums

    NASA Astrophysics Data System (ADS)

    Filimonikhin, G. B.; Filimonikhina, I. I.; Pirogov, V. V.

    2014-07-01

    An isolated mechanical system consisting of a rotating body and two pendulums fit on its longitudinal axis is studied. This system models how pendulum, ball, or fluid (ring) dampers decrease or increase the nutation angle of a spin-stabilized artificial satellite. The conditions of origin, existence, and cessation of the steady-state motion of the system, depending on its parameters, and the stability conditions for the primary motion (the body rotates about the longitudinal axis and the pendulums lie on the same line) and secondary motions (the body does not rotate around the longitudinal axis) are established. The residual nutation angle is estimated

  6. Orbital-Angular-Momentum Mode Selection by Rotationally Symmetric Superposition of Chiral States with Application to Electron Vortex Beams

    NASA Astrophysics Data System (ADS)

    Yang, Yuanjie; Thirunavukkarasu, G.; Babiker, M.; Yuan, Jun

    2017-09-01

    A general orbital-angular-momentum (OAM) mode selection principle is put forward involving the rotationally symmetric superposition of chiral states. This principle is not only capable of explaining the operation of vortex generating elements such as spiral zone plate holograms, but more importantly, it enables the systematic and flexible generation of structured OAM waves in general. This is demonstrated both experimentally and theoretically in the context of electron vortex beams using rotationally symmetric binary amplitude chiral sieve masks.

  7. Orbital-Angular-Momentum Mode Selection by Rotationally Symmetric Superposition of Chiral States with Application to Electron Vortex Beams.

    PubMed

    Yang, Yuanjie; Thirunavukkarasu, G; Babiker, M; Yuan, Jun

    2017-09-01

    A general orbital-angular-momentum (OAM) mode selection principle is put forward involving the rotationally symmetric superposition of chiral states. This principle is not only capable of explaining the operation of vortex generating elements such as spiral zone plate holograms, but more importantly, it enables the systematic and flexible generation of structured OAM waves in general. This is demonstrated both experimentally and theoretically in the context of electron vortex beams using rotationally symmetric binary amplitude chiral sieve masks.

  8. Post-Transition State Dynamics in Gas Phase Reactivity: Importance of Bifurcations and Rotational Activation.

    PubMed

    Martín-Sómer, Ana; Yáñez, Manuel; Hase, William L; Gaigeot, Marie-Pierre; Spezia, Riccardo

    2016-03-08

    Beyond the established use of thermodynamic vs kinetic control to explain chemical reaction selectivity, the concept of bifurcations on a potential energy surface (PES) is proving to be of pivotal importance with regard to selectivity. In this article, we studied by means of post-transition state (TS) direct dynamics simulations the effect that vibrational and rotational excitation at the TS may have on selectivity on a bifurcating PES. With this aim, we studied the post-TS unimolecular reactivity of the [Ca(formamide)](2+) ion, for which Coulomb explosion and neutral loss reactions compete. The PES exhibits different kinds of nonintrinsic reaction coordinate (IRC) dynamics, among them PES bifurcations, which direct the trajectories to multiple reaction paths after passing the TS. Direct dynamics simulations were used to distinguish between the bifurcation non-IRC dynamics and non-IRC dynamics arising from atomistic motions directing the trajectories away from the IRC. Overall, we corroborated the idea that kinetic selectivity often does not reduce to a simple choice between paths with different barrier heights and instead dynamical behavior after passing the TS may be crucial. Importantly, rotational excitation may play a pivotal role on the reaction selectivity favoring nonthermodynamic products.

  9. Rapidly rotating neutron stars in general relativity: Realistic equations of state

    NASA Technical Reports Server (NTRS)

    Cook, Gregory B.; Shapiro, Stuart L.; Teukolsky, Saul A.

    1994-01-01

    We construct equilibrium sequences of rotating neutron stars in general relativity. We compare results for 14 nuclear matter equations of state. We determine a number of important physical parameters for such stars, including the maximum mass and maximum spin rate. The stability of the configurations to quasi-radial perturbations is assessed. We employ a numerical scheme particularly well suited to handle rapid rotation and large departures from spherical symmetry. We provide an extensive tabulation of models for future reference. Two classes of evolutionary sequences of fixed baryon rest mass and entropy are explored: normal sequences, which behave very much like Newtonian sequences, and supramassive sequences, which exist for neutron stars solely because of general relativistic effects. Adiabatic dissipation of energy and angular momentum causes a star to evolve in quasi-stationary fashion along an evolutionary sequence. Supramassive sequences have masses exceeding the maximum mass of a nonrotating neutron star. A supramassive star evolves toward eventual catastrophic collapse to a black hole. Prior to collapse, the star actually spins up as it loses angular momentum, an effect that may provide an observable precursor to gravitational collapse to a black hole.

  10. Unconventional superconductors under a rotating magnetic field. I. Density of states and specific heat

    NASA Astrophysics Data System (ADS)

    Vorontsov, A. B.; Vekhter, I.

    2007-06-01

    We develop a fully microscopic theory for the calculations of the angle-dependent properties of unconventional superconductors under a rotated magnetic field. We employ the quasiclassical Eilenberger equations and use a variation of the Brandt-Pesch-Tewordt (BPT) method to obtain a closed-form solution for the Green’s function. The equations are solved self-consistently for quasi-two-dimensional dx2-y2(dxy) superconductors with the field rotated in the basal plane. The solution is used to determine the density of states and the specific heat. We find that applying the field along the gap nodes may result in minima or maxima in the angle-dependent specific heat, depending on the location in the T-H plane. This variation is attributed to the scattering of the quasiparticles on vortices, which depends on both the field and the quasiparticle energy, and is beyond the reach of the semiclassical approximation. We investigate the anisotropy across the T-H phase diagram and compare our results with the experiments on heavy fermion CeCoIn5 .

  11. Magnetic states of MnP: muon-spin rotation studies

    NASA Astrophysics Data System (ADS)

    Khasanov, R.; Amato, A.; Bonfà, P.; Guguchia, Z.; Luetkens, H.; Morenzoni, E.; De Renzi, R.; Zhigadlo, N. D.

    2017-04-01

    Muon-spin rotation data collected at ambient pressure (p) and at p  =  2.42 GPa in MnP were analyzed to check their consistency with various low- and high-pressure magnetic structures reported in the literature. Our analysis confirms that in MnP the low-temperature and low-pressure helimagnetic phase is characterised by an increased value of the average magnetic moment compared to the high-temperature ferromagnetic phase. An elliptical double-helical structure with a propagation vector \\mathbf{Q}=(0,0,0.117) , an a-axis moment elongated by approximately 18% and an additional tilt of the rotation plane towards c-direction by ≃ 4 –8° leads to a good agreement between the theory and the experiment. The analysis of the high-pressure μSR data reveals that the new magnetic order appearing for pressures exceeding 1.5 GPa can not be described by keeping the propagation vector \\mathbf{Q}\\parallel c . Even the extreme case—decoupling the double-helical structure into four individual helices—remains inconsistent with the experiment. It is shown that the high-pressure magnetic phase which is a precursor of superconductivity is an incommensurate helical state with \\mathbf{Q}\\parallel b .

  12. Rapidly rotating neutron stars in general relativity: Realistic equations of state

    NASA Technical Reports Server (NTRS)

    Cook, Gregory B.; Shapiro, Stuart L.; Teukolsky, Saul A.

    1994-01-01

    We construct equilibrium sequences of rotating neutron stars in general relativity. We compare results for 14 nuclear matter equations of state. We determine a number of important physical parameters for such stars, including the maximum mass and maximum spin rate. The stability of the configurations to quasi-radial perturbations is assessed. We employ a numerical scheme particularly well suited to handle rapid rotation and large departures from spherical symmetry. We provide an extensive tabulation of models for future reference. Two classes of evolutionary sequences of fixed baryon rest mass and entropy are explored: normal sequences, which behave very much like Newtonian sequences, and supramassive sequences, which exist for neutron stars solely because of general relativistic effects. Adiabatic dissipation of energy and angular momentum causes a star to evolve in quasi-stationary fashion along an evolutionary sequence. Supramassive sequences have masses exceeding the maximum mass of a nonrotating neutron star. A supramassive star evolves toward eventual catastrophic collapse to a black hole. Prior to collapse, the star actually spins up as it loses angular momentum, an effect that may provide an observable precursor to gravitational collapse to a black hole.

  13. Rotational Spectra of Urea in its Ground and First Excited Vibrational States

    NASA Astrophysics Data System (ADS)

    Thomas, Jessica; Medvedev, Ivan; Kisiel, Zbigniew

    2014-06-01

    Urea is an important terrestrial bio-molecule, which has been tentatively detected in the interstellar medium. To match the much improved range and sensitivities of modern sub-millimeter telescopes a broad laboratory assay of rotational transitions needs to be recorded in order to aid in the definitive identification of this molecule. This paper focuses on the spectroscopic assignment of the rotational transitions of urea in the 207-500 GHz range which belong to its ground and first excited vibrational states. Remijan, A.J., L.E. Snyder, B.A. McGuire, H.-L. Kuo, L.W. Looney, D.N. Friedel, G.Y. Golubiatnikov, F.J. Lovas, V.V. Ilyushin, E.A. Alekseev, S.F. Dyubko, B.J. McCall, and J.M. Hollis, Observational Results of a Multi-Telescope Campaign in Search of Interstellar Urea [NH22CO]. The Astrophysical Journal, 2014. 783(2): p. 77

  14. Rotational state-changing cold collisions of hydroxyl ions with helium

    NASA Astrophysics Data System (ADS)

    Hauser, Daniel; Lee, Seunghyun; Carelli, Fabio; Spieler, Steffen; Lakhmanskaya, Olga; Endres, Eric S.; Kumar, Sunil S.; Gianturco, Franco; Wester, Roland

    2015-06-01

    Cold molecules are important for many applications, from fundamental precision measurements, quantum information processing, quantum-controlled chemistry, to understanding the cold interstellar medium. Molecular ions are known to be cooled efficiently in sympathetic collisions with cold atoms or ions. However, little knowledge is available on the elementary cooling steps, because the determination of quantum state-to-state collision rates at low temperature is very challenging for both experiment and theory. Here we present a method to manipulate molecular quantum states by non-resonant photodetachment. Based on this we provide absolute quantum scattering rate coefficients under full quantum state control for the rotationally inelastic collision of hydroxyl anions with helium. Experiment and quantum scattering theory show excellent agreement without adjustable parameters. Very similar rate coefficients are obtained for two different isotopes, which is linked to several quantum scattering resonances appearing at different energies. The presented method is also applicable to polyatomic systems and will help elucidate non-radiative processes in polyaromatic hydrocarbons and protein chromophores.

  15. Fully relativistic rovibrational energies and spectroscopic constants of the lowest X:(1)0(+)g, A':(1)2( u ), A:(1)1 ( u ), B':(1)0(-)u and B:(1)0(+)u states of molecular chlorine.

    PubMed

    Machado, Daniel F S; Silva, Valter H C; Esteves, Cristiano S; Gargano, Ricardo; Macedo, Luiz G M; Mundim, Kleber C; de Oliveira, Heibbe C B

    2012-09-01

    The main goal of this paper is to present the rovibrational energies and spectroscopic constants of the Cl(2) molecular system in the relativistic states [Formula: see text], A':(1)2( u ), A:(1)1( u ), [Formula: see text] and [Formula: see text]. More precisely, we have evaluated the Cl(2) ω ( e ), ω ( e ) x ( e ), ω ( e ) y ( e ), α ( e ), γ ( e ) and B ( e ) rovibrational spectroscopic constants using two different procedures. The first was obtained by combining the rovibrational energies, calculated through solving Schrödinger's nuclear equation and the diatomic rovibrational energy equation. The second was obtained by using the Dunham method. The calculated properties are in good agreement with available experimental data.

  16. Optically induced rotation of Rayleigh particles by vortex beams with different states of polarization

    NASA Astrophysics Data System (ADS)

    Li, Manman; Yan, Shaohui; Yao, Baoli; Liang, Yansheng; Lei, Ming; Yang, Yanlong

    2016-01-01

    Optical vortex beams carry optical orbital angular momentum (OAM) and can induce an orbital motion of trapped particles in optical trapping. We show that the state of polarization (SOP) of vortex beams will affect the details of this optically induced orbital motion to some extent. Numerical results demonstrate that focusing the vortex beams with circular, radial or azimuthal polarizations can induce a uniform orbital motion on a trapped Rayleigh particle, while in the focal field of the vortex beam with linear polarization the particle experiences a non-uniform orbital motion. Among the formers, the vortex beam with circular polarization induces a maximum optical torque on the particle. Furthermore, by varying the topological charge of the vortex beams, the vortex beam with circular polarization gives rise to an optimum torque superior to those given by the other three vortex beams. These facts suggest that the circularly polarized vortex beam is more suitable for rotating particles.

  17. Asteroid 2867 Steins. II. Multi-telescope visible observations, shape reconstruction, and rotational state

    NASA Astrophysics Data System (ADS)

    Lamy, P. L.; Kaasalainen, M.; Lowry, S.; Weissman, P.; Barucci, M. A.; Carvano, J.; Choi, Y.-J.; Colas, F.; Faury, G.; Fornasier, S.; Groussin, O.; Hicks, M. D.; Jorda, L.; Kryszczynska, A.; Larson, S.; Toth, I.; Warner, B.

    2008-09-01

    Context: Asteroid 2867 Steins is the first target of the Rosetta space mission with a flyby scheduled in September 2008. Aims: An early physical characterization is needed to optimize the flyby parameters and the science operations, and to maximize the scientific return. The aim of this article is to characterize the shape and rotational state of this asteroid. Methods: We compile a set of 26 visible light curves whose phase angle coverage extends from 7.5° to 41.7°, and perform their simultaneous inversion relying on convex modeling. Results: The full three-dimensional solution for asteroid 2867 Steins is rather spherical with axial ratios a/b=1.17 and a/c=1.25. The rotational state is characterized by a sidereal period of 6.04681 ± 0.00002 h, and the pole direction defined by its ecliptic coordinates λ ≈ 250° and β ≈ - 89° has an uncertainty of about 5°. It is therefore almost exactly perpendicular to the ecliptic plane, and the viewing geometries are thus restricted to only ±20° about Steins' equator. Consequently, the shape model is not strongly constrained, and the polar flattening has an uncertainty of about 10%. Inversion is basically scale-free, and absolute scaling comes from a measurement of its thermal emission with the Spitzer Space Telescope (Lamy et al. 2008, A&A, 487, 1187), yielding overall dimensions of 5.73 ± 0.52, 4.95±0.45, and 4.58 ± 0.41 km.

  18. Accurate study on the quantum dynamics of the He + HeH(+) (X1Σ+) reaction on a new ab initio potential energy surface for the lowest 1(1)A' electronic singlet state.

    PubMed

    Xu, Wenwu; Zhang, Peiyu

    2013-02-21

    A time-dependent quantum wave packet method is used to investigate the dynamics of the He + HeH(+)(X(1)Σ(+)) reaction based on a new potential energy surface [Liang et al., J. Chem. Phys.2012, 136, 094307]. The coupled channel (CC) and centrifugal-sudden (CS) reaction probabilities as well as the total integral cross sections are calculated. A comparison of the results with and without Coriolis coupling revealed that the number of K states N(K) (K is the projection of the total angular momentum J on the body-fixed z axis) significantly influences the reaction threshold. The effective potential energy profiles of each N(K) for the He + HeH(+) reaction in a collinear geometry indicate that the barrier height gradually decreased with increased N(K). The calculated time evolution of CC and CS probability density distribution over the collision energy of 0.27-0.36 eV at total angular momentum J = 50 clearly suggests a lower reaction threshold of CC probabilities. The CC cross sections are larger than the CS results within the entire energy range, demonstrating that the Coriolis coupling effect can effectively promote the He + HeH(+) reaction.

  19. Stress-free states of continuum dislocation fields: Rotations, grain boundaries, and the Nye dislocation density tensor

    NASA Astrophysics Data System (ADS)

    Limkumnerd, Surachate; Sethna, James P.

    2007-06-01

    We derive general relations between grain boundaries, rotational deformations, and stress-free states for the mesoscale continuum Nye dislocation density tensor. Dislocations generally are associated with long-range stress fields. We provide the general form for dislocation density fields whose stress fields vanish. We explain that a grain boundary (a dislocation wall satisfying Frank’s formula) has vanishing stress in the continuum limit. We show that the general stress-free state can be written explicitly as a (perhaps continuous) superposition of flat Frank walls. We show that the stress-free states are also naturally interpreted as configurations generated by a general spatially dependent rotational deformation. Finally, we propose a least-squares definition for the spatially dependent rotation field of a general (stressful) dislocation density field.

  20. Deterministic multi-step rotation of magnetic single-domain state in Nickel nanodisks using multiferroic magnetoelastic coupling

    NASA Astrophysics Data System (ADS)

    Sohn, Hyunmin; Liang, Cheng-yen; Nowakowski, Mark E.; Hwang, Yongha; Han, Seungoh; Bokor, Jeffrey; Carman, Gregory P.; Candler, Robert N.

    2017-10-01

    We demonstrate deterministic multi-step rotation of a magnetic single-domain (SD) state in Nickel nanodisks using the multiferroic magnetoelastic effect. Ferromagnetic Nickel nanodisks are fabricated on a piezoelectric Lead Zirconate Titanate (PZT) substrate, surrounded by patterned electrodes. With the application of a voltage between opposing electrode pairs, we generate anisotropic in-plane strains that reshape the magnetic energy landscape of the Nickel disks, reorienting magnetization toward a new easy axis. By applying a series of voltages sequentially to adjacent electrode pairs, circulating in-plane anisotropic strains are applied to the Nickel disks, deterministically rotating a SD state in the Nickel disks by increments of 45°. The rotation of the SD state is numerically predicted by a fully-coupled micromagnetic/elastodynamic finite element analysis (FEA) model, and the predictions are experimentally verified with magnetic force microscopy (MFM). This experimental result will provide a new pathway to develop energy efficient magnetic manipulation techniques at the nanoscale.

  1. Vibration-rotation-tunneling states of the benzene dimer: an ab initio study.

    PubMed

    van der Avoird, Ad; Podeszwa, Rafał; Szalewicz, Krzysztof; Leforestier, Claude; van Harrevelt, Rob; Bunker, P R; Schnell, Melanie; von Helden, Gert; Meijer, Gerard

    2010-08-01

    An improved intermolecular potential surface for the benzene dimer is constructed from interaction energies computed by symmetry-adapted perturbation theory, SAPT(DFT), with the inclusion of third-order contributions. Twelve characteristic points on the surface have been investigated also using the coupled-cluster method with single, double, and perturbative triple excitations, CCSD(T), and triple-zeta quality basis sets with midbond functions. The SAPT and CCSD(T) results are in close agreement and provide the best representation of these points to date. The potential was used in calculations of vibration-rotation-tunneling (VRT) levels of the dimer by a method appropriate for large amplitude intermolecular motions and tunneling between multiple equivalent minima in the potential. The resulting VRT levels were analyzed with the use of the permutation-inversion full cluster tunneling (FCT) group G(576) and a chain of subgroups that starts from the molecular symmetry group C(s)(M) of the rigid dimer at its equilibrium C(s) geometry and leads to G(576) if all possible intermolecular tunneling mechanisms are feasible. Further information was extracted from the calculated wave functions. It was found, in agreement with the experimental data, that for all of the 54 G(576) symmetry species (with different nuclear spin statistical weights) the lower VRT states have a tilted T-shape (TT) structure; states with the parallel-displaced structure are higher in energy than the ground state of A symmetry by at least 30 cm(-1). The dissociation energy D(0) equals 870 cm(-1), while the depth D(e) of the TT minimum in the potential is 975 cm(-1). Hindered rotation of the cap in the TT structure and tilt tunneling lead to level splittings on the order of 1 cm(-1). Also intermolecular vibrations with excitation energies starting at a few cm(-1) were identified. A further small, but probably significant, level splitting was assigned to cap turnover, although in scans of the potential

  2. Thermalization of rotational states of NO A 2Σ+(v = 0) in an atmospheric pressure plasma

    NASA Astrophysics Data System (ADS)

    van Gessel, A. F. H.; Bruggeman, P. J.

    2013-05-01

    Laser induced fluorescence (LIF) measurements of nitric oxide (NO) are performed in an atmospheric pressure microwave plasma jet, operated with a mixture of He and 3% air. The fluorescence signal of NO A 2Σ+(v = 0) is measured time and fluorescence wavelength resolved. Based on the evolution of the rotational spectrum at different positions in the plasma, we determined the thermalization time of the rotational distribution of NO A after pumping a single transition, at temperatures in the range 300-1500 K. Also, a LIF-RET (rotational energy transfer) model is developed to simulate the RET and to calculate the thermalization time. The RET rate coefficients are calculated using the energy corrected sudden-exponential power scaling law. It was found that it is necessary to take the fine structure of the rotational states into account. At room temperature the results of the measurement and the simulation are consistent, and the thermalization occurs during the laser pulse (11 ± 1 ns). At elevated temperatures the measurements show a large increase in thermalization time, up to 35 ± 4 ns at 1474 K. This time is much longer than the laser pulse, and of the order of the NO A lifetime. This means that for spectroscopy measurements of the rotational states of NO A, the RET has to be taken into account to derive gas temperatures from the rotational distribution of NO A.

  3. Mars' rotational state and tidal deformations from radio interferometry of a network of landers.

    NASA Astrophysics Data System (ADS)

    Iess, L.; Giuliani, S.; Dehant, V.

    2012-04-01

    The precise determination of the rotational state of solar system bodies is one of the main tools to investigate their interior structure. Unfortunately the accuracies required for geophysical interpretations are very stringent, and generally unattainable from orbit using optical or radar tracking of surface landmarks. Radio tracking of a lander from ground or from a spacecraft orbiting the planet offers substantial improvements, especially if the lander lifetime is adequately long. The optimal configuration is however attained when two or more landers can be simultaneously tracked from a ground antenna in an interferometric mode. ESA has been considering a network of landers on Mars since many years, and recently this concept has been revived by the study of the Mars Network Science Mission (MNSM). The scientific rationale of MNSM is the investigation of the Mars' interior and atmosphere by means of a network of two or three landers, making it especially suitable for interferometric observations. In order to synthesize an interferometer, the MNSN landers must be tracked simultaneously from a single ground antenna in a coherent two-way mode. The uplink radio signal (at X- or Ka-band) is received by the landers' transponders and retransmitted to ground in the same frequency band. The signals received at ground station are then recorded (typically at few tens of kHz) and beaten against each other to form the output of the interferometer, a complex phasor. The differential phase retain information on Mars' rotational parameters and tidal deformations. A crucial aspect of the interferometric configuration is the rejection of common noise and error sources. Errors in the station location, Earth orientation parameters and ephemerides, path delays due to the Earth troposphere and ionosphere, and, to a good extent, interplanetary plasma are cancelled out. The main residual errors are due to differential path delays from Mars' atmosphere and differential drifts of the

  4. Cryo-EM structures of the autoinhibited E. coli ATP synthase in three rotational states

    PubMed Central

    Sobti, Meghna; Smits, Callum; Wong, Andrew SW; Ishmukhametov, Robert; Stock, Daniela; Sandin, Sara; Stewart, Alastair G

    2016-01-01

    A molecular model that provides a framework for interpreting the wealth of functional information obtained on the E. coli F-ATP synthase has been generated using cryo-electron microscopy. Three different states that relate to rotation of the enzyme were observed, with the central stalk’s ε subunit in an extended autoinhibitory conformation in all three states. The Fo motor comprises of seven transmembrane helices and a decameric c-ring and invaginations on either side of the membrane indicate the entry and exit channels for protons. The proton translocating subunit contains near parallel helices inclined by ~30° to the membrane, a feature now synonymous with rotary ATPases. For the first time in this rotary ATPase subtype, the peripheral stalk is resolved over its entire length of the complex, revealing the F1 attachment points and a coiled-coil that bifurcates toward the membrane with its helices separating to embrace subunit a from two sides. DOI: http://dx.doi.org/10.7554/eLife.21598.001 PMID:28001127

  5. Anomalous Vortex States of (Pr,Y)BCO: an ME Muon-spin-rotation Study

    NASA Astrophysics Data System (ADS)

    Tun, M.; Aslanian, H. H.; Cavanaugh, S. X.; Santiago, R. D.; Boekema, C.

    2001-03-01

    Muon-spin-rotation vortex data of polycrystalline Pr(x)Y(1-x)BCO (0 < x < 0.4) have been analyzed by a Maximum-Entropy (ME) Burg technique. The samples were field cooled in 1-kOe transverse fields. We are studying the effect of low Pr doping (x = 0.2 and 0.4) on the magnetic field distributions in the (Pr,Y)BCO vortex states. Well below Tc, we have found anomalies in the vortex field distributions, as seen earlier for RBCO [1]. For instance, the unusual low field tails observed below about 35 K start about 600 Oe and vary slightly with x. This tail does not occur for chainless Bi&Tl cuprate vortex states. [2] Thus, we suggest that this low field tail could be related to superconducting condensation in the CuO-chain layer, as indicated by other evidence. [3] Further work is in progress and will be discussed. Research is supported by NSF-REU, DOE-LANL and WiSE@SJSU. 1] Alves et al, Phys Rev B49 (1994) 12396; Boekema et al, Physica C282-287 (1997) 2069; Santiago et al, Phys Rev B submitted. [2] Santiago et al, M2S-HTSC-VI Conf Proc, Physica C (2000) [3] Tallon et al, Phys Rev Lett 74 (1995) 1008; Phys Rev B53 (1996) R11972.

  6. The structure of the Hoyle state via a measurement of the 'Hoyle Rotational Band' in 12C

    NASA Astrophysics Data System (ADS)

    Gai, M.; UConn-Yale-TUNL-Weizmann-PTB-UCL Collaboration

    2013-04-01

    We have measured the 12C(γ, 3α) reaction with an Optical Time Projection Chamber (O-TPC) detector operating with the CO2(80%) + N2(20%) gas mixture and gamma-ray beams from the HIγS facility of the TUNL at Duke. We measured complete angular distributions (between 9.1 - 10.7 MeV) from which we determine the cross section yield curve and E1-E2 relative phases leading to an unambiguous identification of the second 2+ state in 12C at 10.03(11) MeV. The observed spectrum of 12C below 12 MeV including the 2+2 observed in this work resembles the rotation-vibration spectrum predicted for a triangular shape oblate spinning top in which the Hoyle state is the first vibrational breathing mode of the triangular three alpha particle system. The predicted rotation-vibration spectrum of a triangular shape oblate spinning top (with a D3h symmetry) allows us to compare the moment of inertia of the predicted Hoyle rotational band to the ground state rotational band and in this way extract the model radius parameter of the Hoyle state of 3.22(8) fm ( time the r.m.s. radius of the ground state) which is close to the radius extracted from 12C(x,x') data.

  7. Rotationally resolved photoelectron spectra in resonance enhanced multiphoton ionization of HCl via the F 1Δ2 Rydberg state

    NASA Astrophysics Data System (ADS)

    Wang, Kwanghsi; McKoy, V.

    1991-12-01

    Results of studies of rotational ion distributions in the X 2Π3/2 and X 2Π1/2 spin-orbit states of HCl+ resulting from (2+1') resonance enhanced multiphoton ionization (REMPI) via the S(0) branch of the F 1Δ2 Rydberg state are reported and compared with measured threshold-field-ionization zero-kinetic-energy spectra reported recently [K. S. Haber, Y. Jiang, G. Bryant, H. Lefebvre-Brion, and E. R. Grant, Phys. Rev. A (in press)]. These results show comparable intensities for J+=3/2 of the X 2Π3/2 ion and J+=1/2 of the X 2Π1/2 ion. Both transitions require an angular momentum change of ΔN=-1 upon photoionization. To provide further insight into the near-threshold dynamics of this process, we also show rotationally resolved photoelectron angular distributions, alignment of the ion rotational levels, and rotational distributions for the parity components of the ion rotational levels. About 18% population is predicted to occur in the (+) parity component, which would arise from odd partial-wave contributions to the photoelectron matrix element. This behavior is similar to that in (2+1) REMPI via the S(2) branch of the F 1Δ2 state of HBr and was shown to arise from significant l mixing in the electronic continuum due to the nonspherical molecular ion potential. Rotational ion distributions resulting from (2+1) REMPI via the S(10) branch of the F 1Δ2 state are also shown.

  8. Planarized and Twisted Intramolecular Charge Transfer: A Concept for Fluorophores Showing Two Independent Rotations in Excited State.

    PubMed

    Haberhauer, Gebhard

    2017-07-12

    TICT (twisted intramolecular charge transfer) compounds are characterized by showing a rotation around a single bond in the excited state: starting from an almost planar geometry in the ground state, a twisted system is formed in the electronic excited state. The previously reported PLICT (planarized intramolecular charge transfer) compounds show inverse behavior: starting from a twisted geometry in the electronic ground state, a planarized system is formed in the excited state by rotation around a single bond. Here, a concept for planarized and twisted intramolecular charge transfer (PLATICT) states is presented which amalgamates both (TICT and PLICT) effects. Due to an intramolecular charge transfer, both a twisting around one single bond and a planarization around another one occurs. In sum, the PLATICT system shows two independent rotations around different axes in the excited state. By means of quantum chemical calculations (TD-cam-B3LYP and CC2) and experimental studies, it is demonstrated that N-aryl-substituted 1-aminoindoles are able to form photoinduced PLATICT states. In the fluorescence spectra of N-aryl-substituted 1-aminoindoles with a methoxycarbonyl or a cyano group as substituent in the aryl ring, very large Stokes shifts (ca. 18 000 cm(-1) ; >250 nm) are observed. The two independent rotations in the excited state, the very large Stokes shifts and their easy availability starting from indoline, make them very attractive for use as optical switches and motors in various fields of chemistry. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Vortices as quantum objects in the lowest Landau level

    SciTech Connect

    Bourne, A.; Gunn, J. M. F.; Wilkin, N. K.

    2007-11-15

    We provide a quantum description of the vortex degrees of freedom for Bose gases in the lowest Landau level. The results can be used to interpret correlated many-particle wave functions in terms of superpositions of vortex configurations. These effects may be visible in the next generation of mesoscopic trap experiments. We expose the important role of nonorthogonality in using simple vortex descriptions, and formulate a basis set which does not experience these difficulties. We show that in general any correlated ground state (even completely fragmented) can be represented as a superposition of completely condensed states. We provide simple illustrations of these methods: a vortex interpretation of the exact, many-body, eigenstates for L{<=}N, the determination of the energy levels of the single-vortex subspace and finally mention a more speculative description of the Laughlin state in vortex variables.

  10. Vortex states and spin textures of rotating spin-orbit-coupled Bose-Einstein condensates in a toroidal trap

    NASA Astrophysics Data System (ADS)

    Wang, Huan; Wen, Linghua; Yang, Hui; Shi, Chunxiao; Li, Jinghong

    2017-08-01

    We consider the ground-state properties of Rashba spin-orbit-coupled pseudo-spin-1/2 Bose-Einstein condensates (BECs) in a rotating two-dimensional (2D) toroidal trap. In the absence of spin-orbit coupling (SOC), the increasing rotation frequency enhances the creation of giant vortices for the initially miscible BECs, while it can lead to the formation of semiring density patterns with irregular hidden vortex structures for the initially immiscible BECs. Without rotation, strong 2D isotropic SOC yields a heliciform-stripe phase for the initially immiscible BECs. Combined effects of rotation, SOC, and interatomic interactions on the vortex structures and typical spin textures of the ground state of the system are discussed systematically. In particular, for a fixed rotation frequency above the critical value, the increasing isotropic SOC favors a visible vortex necklace in each component which is accompanied by a hidden giant vortex plus a (several) hidden vortex necklace(s) in the central region. In the case of one-dimensional anisotropic SOC, large SOC strength results in the generation of hidden linear vortex string and the transition from initial component separation (component mixing) to component mixing (component separation). Furthermore, the peculiar spin textures including skyrmion lattice, skyrmion pair and skyrmion string are revealed in this system.

  11. The S 1, 1A 2(n,π*) state of acetone in a supersonic nozzle beam. Methyl internal rotation

    NASA Astrophysics Data System (ADS)

    Baba, Masaaki; Hanazaki, Ichiro

    1983-12-01

    Fluorescence excitation spectra of the S 1, 1A 2(n, π*) state of acetone and acetone- d6 have been measured. Active vibrational modes are the CH 3 torsion and the CO out-of-plane wagging. The barriers to internal rotation, V3, for acetone and acetone- d6 in the S 1 state have been estimated to be 740 ± 90 and 720 ± 60 cm -1, respectively.

  12. High-Resolution Faraday Rotation and Electron-Phonon Coupling in Surface States of the Bulk-Insulating Topological Insulator Cu_{0.02}Bi_{2}Se_{3}.

    PubMed

    Wu, Liang; Tse, Wang-Kong; Brahlek, M; Morris, C M; Aguilar, R Valdés; Koirala, N; Oh, S; Armitage, N P

    2015-11-20

    We have utilized time-domain magnetoterahertz spectroscopy to investigate the low-frequency optical response of the topological insulator Cu_{0.02}Bi_{2}Se_{3} and Bi_{2}Se_{3} films. With both field and frequency dependence, such experiments give sufficient information to measure the mobility and carrier density of multiple conduction channels simultaneously. We observe sharp cyclotron resonances (CRs) in both materials. The small amount of Cu incorporated into the Cu_{0.02}Bi_{2}Se_{3} induces a true bulk insulator with only a single type of conduction with a total sheet carrier density of ~4.9×10^{12}/cm^{2} and mobility as high as 4000 cm^{2}/V·s. This is consistent with conduction from two virtually identical topological surface states (TSSs) on the top and bottom of the film with a chemical potential ~145 meV above the Dirac point and in the bulk gap. The CR broadens at high fields, an effect that we attribute to an electron-phonon interaction. This assignment is supported by an extended Drude model analysis of the zero-field Drude conductance. In contrast, in normal Bi_{2}Se_{3} films, two conduction channels were observed, and we developed a self-consistent analysis method to distinguish the dominant TSSs and coexisting trivial bulk or two-dimensional electron gas states. Our high-resolution Faraday rotation spectroscopy on Cu_{0.02}Bi_{2}Se_{3} paves the way for the observation of quantized Faraday rotation under experimentally achievable conditions to push the chemical potential in the lowest Landau level.

  13. Lifetimes of Vibro-Rotational Levels in Excited Electronic States of Diatomic Hydrogen Isotopologues

    SciTech Connect

    Astashkevich, S. A. Lavrov, B. P.

    2015-06-15

    The current situation in studies of lifetimes of excited rovibronic levels for the H{sub 2}, D{sub 2}, T{sub 2}, HD, HT, and DT molecules is analyzed. All measured lifetime values (792 entries for 618 different vibro-rotational levels of 33 electronic states) reported in 61 publications before April 2015 are compiled and listed in tabular format together with an annotated bibliography. Experimental data are only available for the H{sub 2}, HD, and D{sub 2} molecules. The data collected in the present work show fragmentariness of experimental data. For the vast majority of the levels, the lifetime values were reported in one paper only and up to now are without independent experimental verification. A complete bibliography of publications concerning semiempirical determination and nonempirical calculations of the lifetimes is presented. Numerical results obtained in the framework of these two approaches are listed only in cases when experimental data are available. For more than half of the levels, the differences between measured and calculated values are three times higher than experimental errors. These discrepancies show necessity of more precise experimental and nonempirical studies. For some 79 rovibronic levels, our analysis makes it possible to propose certain set of recommended lifetime values.

  14. Lifetimes of Vibro-Rotational Levels in Excited Electronic States of Diatomic Hydrogen Isotopologues

    NASA Astrophysics Data System (ADS)

    Astashkevich, S. A.; Lavrov, B. P.

    2015-06-01

    The current situation in studies of lifetimes of excited rovibronic levels for the H2, D2, T2, HD, HT, and DT molecules is analyzed. All measured lifetime values (792 entries for 618 different vibro-rotational levels of 33 electronic states) reported in 61 publications before April 2015 are compiled and listed in tabular format together with an annotated bibliography. Experimental data are only available for the H2, HD, and D2 molecules. The data collected in the present work show fragmentariness of experimental data. For the vast majority of the levels, the lifetime values were reported in one paper only and up to now are without independent experimental verification. A complete bibliography of publications concerning semiempirical determination and nonempirical calculations of the lifetimes is presented. Numerical results obtained in the framework of these two approaches are listed only in cases when experimental data are available. For more than half of the levels, the differences between measured and calculated values are three times higher than experimental errors. These discrepancies show necessity of more precise experimental and nonempirical studies. For some 79 rovibronic levels, our analysis makes it possible to propose certain set of recommended lifetime values.

  15. The millimeter-wave rotational spectrum of CF 3CN in the excited vibrational state v8 = 2

    NASA Astrophysics Data System (ADS)

    Motamedi, Masoud; Haseli, Aliakbar

    2006-03-01

    The millimeter-wave rotational spectra of the excited vibrational state v8 = 2 of the symmetric top molecule, CF 3CN, have been recorded for J″ = 16 up to J″ = 32. The analysis indicates that ℓ-resonance has been observed for this molecule around ( k - ℓ) = 25. The ℓ = ±2 and ℓ = 0 series have been assigned and the spectra analyzed to give rotational parameters including B = 2955.46351(49) MHz, Xℓℓ = 8783.6(78) MHz, and qt+(2,2)=3.4673(20) MHz.

  16. E 2 decay strength of the M 1 scissors mode of 156Gd and its first excited rotational state

    NASA Astrophysics Data System (ADS)

    Beck, T.; Beller, J.; Pietralla, N.; Bhike, M.; Birkhan, J.; Derya, V.; Gayer, U.; Hennig, A.; Isaak, J.; Löher, B.; Ponomarev, V. Yu.; Richter, A.; Romig, C.; Savran, D.; Scheck, M.; Tornow, W.; Werner, V.; Zilges, A.; Zweidinger, M.

    2017-05-01

    The E 2 /M 1 multipole mixing ratio δ1 →2 of the 1sc+→21+ γ -ray decay in 156Gd and hence the isovector E 2 transition rate of the scissors mode of a well-deformed rotational nucleus has been measured for the first time. It has been obtained from the angular distribution of an artificial quasimonochromatic linearly polarized γ -ray beam of energy 3.07(6) MeV scattered inelastically off an isotopically highly enriched 156Gd target. The data yield first direct support for the deformation dependence of effective proton and neutron quadrupole boson charges in the framework of algebraic nuclear models. First evidence for a low-lying Jπ=2+ member of the rotational band of states on top of the 1+ band head is obtained, too, indicating a significant signature splitting in the K =1 scissors mode rotational band.

  17. Long-term Rotation State Evolution of Comet Nuclei Including the Effects of Jet Torques and Internal Dissipation

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Scheeres, D. J.

    2012-05-01

    Many comet nuclei have been identified or are suspected to occupy non-principal axis (complex) rotation [Belton 2005, etc.] as well as have evolving rotation rates [Belton 2011, etc.]. Active areas of the surface and jets torque the nucleus during perihelion passage, while time variable internal stresses dissipate energy in the anelastic comet interior. These competing processes determine the comet’s nuclear rotation state. We developed a model for the evolution of the nuclei due to the reactive torques of a number of discrete jets located on the surface based on Neishtadt et al. [2002]. These jets are active only within a specific distance of the sun according to an empirical law determined by Marsden et al. (1973), however internal dissipation occurs as long as the body is not rotating about a principal axis. This internal dissipation is modeled according to Sharma et al. [2005] and Vokrouhlicky et al. [2009]. We average the full evolutionary equations over the rapidly changing spin angle, precession angle and true anomaly of the orbit. The averaged equations can rapidly calculate the long-term evolution of the nutation angle, cone angle and magnitude of the angular momentum vector over many perihelion passages. The averaged dynamical system is characterized by just two parameters: the first encapsulating the jet geometry and the second the coefficient of energy dissipation. Neishtadt et al. [2002] determined that there exist non-principal axis rotation fixed points, some even stable, for certain jet geometries. With the addition of internal dissipation, some of these fixed points disappear, while others remain but may change locations and classification as a function of the strength of energy dissipation at constant jet geometry. We explore this model of comet nuclei evolution to determine the rotation state of comet nuclei with changing jet geometries and constant coefficients of energy dissipation.

  18. Rotational energy surface and quasiclassical analysis of the rotational energy level cluster formation in the ground vibrational state of PH 3

    NASA Astrophysics Data System (ADS)

    Petrov, Sergey V.; Kozlovskii, Borislav M.

    2007-06-01

    We report and substantiate a method for constructing the rotational energy surface (RES) of a molecule as a pure classical object. For an arbitrary molecule we start from the potential energy surface rather than from a conventional "effective Hamiltonian". The method is used for constructing the RES of the PH 3 molecule in its ground vibrational state. We have used an ab initio potential energy surface [D. Wang, Q. Shi, Q.-S. Zhu, J. Chem. Phys. 112 (2000) 9624-9631; S.N. Yurchenko, M. Carvajal, P. Jensen, F. Herregodts, T.R. Huet, Chem. Phys. 290 (2003) 59-67.]. The shape of the RES is shown not to change for J from 0 to 120. The procedure of quasiclassical quantization of the RES was also undertaken, yielding a set of quasiclassical critical values of the angular momentum. The results explain the structure of quantum rotational energy levels obtained by variational calculations [S.N. Yurchenko, W. Thiel, S. Patchkovskii, P. Jensen, Phys. Chem. Chem. Phys. 7 (2005) 573-582].

  19. Rotation and inversion in nitrosamines

    NASA Astrophysics Data System (ADS)

    Kirste, Karl; Rademacher, Paul

    1981-04-01

    Geometry optimizations of the ground states as well as of the transition states for internal rotation and inversion have been performed by the semiempirical MNDO method for dimethyl nitrosamine (1), perfluordimethyl nitrosamine (2), N-nitroso aziridine (3), and N-nitroso azetidine (4). It was found that the potential barrier to internal rotation about the N-N bond is always of lower energy than that to inversion on the nitroso nitrogen. While the ground states tend to adopt structures which enable mesomerism, the lowest transition state is characterized by a pyramidal sp3-hybridized amino nitrogen. In accordance with experimental results the low barriers to rotation of 2 (7.96 kcal mol -1), 3 (3.38 kcal mol -1) and 4 (9.97 kcal mol -1) in comparison with 1 (12.54 kcal mol -1) indicate that in donor-acceptor molecules the transfer of charge can be limited by electronic and stereochemical effects. In particular, the equivalence of the α-methylene hydrogens which was observed in the NMR-spectrum of 3 is due to unhindered rotation and ring inveirsion.

  20. Changes in the structure of nuclei between the magic neutron numbers 50 and 82 as indicated by a rotating-cluster analysis of the energy values of the first 2j excited states of isotopes of cadmium

    SciTech Connect

    Pauling, L.

    1981-09-01

    Values of R, the radius of rotation of the rotating cluster, are calculated from the observed values of the energy of the lowest 2/sup +/ states of the even isotopes of Cd, Sn, and Te with the assumption that the cluster is ..cap alpha.., pb, and ..cap alpha.., respectively. R shows a maximum at approx. N = 58, a minimum at approx. N = 62, and a second maximum at approx. N = 70. The increase to the first maximum is interpreted as resulting from the overcrowding of spherons (alphas and tritons) in the mantle (outer layer) of the nuclei, causing the cluster to change from rotating in the mantle to skimming over its surface; the decrease to the minimum results from the addition of three dineutrons to the core, expanding the mantle and permitting the rotating cluster to begin to drop back into it; and the increase to the second maximum results from the overcrowding of the larger mantle surrounding the core containing the semimagic number 14 of neutrons rather than the magic numbers 8 for N = 50. The decrease after the second maximum results from the further increase in the number of core neutrons to 20, corresponding to the magic number 82. Some additional evidence for the change to an intermediate structure between N = 50 and N = 82 is also discussed.

  1. The rotation state of 4015 Wilson-Harrington: Revisiting origins for the near-Earth asteroids

    NASA Technical Reports Server (NTRS)

    Osip, DAVIDJ.; Campins, H.; Schleicher, David G.

    1995-01-01

    CCD photometry performed on the comet-asteroid transition object 4015 Wilson-Harrington during its most recent apparition has provided a new rotational lightcurve with a standard double-peaked rotational period of 6.1 +/- 0.05 hr and an amplitude of 0.2 magnitudes. The size, rotation period, and lightcurve amplitude of this object are all similar to values found for near-Earth asteroids (NEA) and small main-belt asteroids. However, these values vary significantly from those of any previously well-studied cometary nuclei. In short, the range in cometary nuclear properties is greater than that indicated by the comets studied previously and although the statistics are still poor, the size and rotational properties of 4015 Wilson-Harrington do suggest that some fraction of NEAs are of cometary origin.

  2. Zero-energy states in rotating trapped Bose-Einstein condensates.

    PubMed

    Simula, Tapio

    2013-07-17

    We have calculated low-lying quasiparticle excitation spectra of rotating three-dimensional Bose-Einstein condensates. We find, as opposed to the prediction of hydrodynamic continuum theories, a minimum in the Tkachenko mode spectrum at intermediate rotation frequencies of the harmonic trap. Such a minimum can harbour a Tkachenko quasiparticle with zero excitation energy. We discuss the experimental signatures of such a zero mode.

  3. Anisotropic non-gaussianity from rotational symmetry breaking excited initial states

    SciTech Connect

    Ashoorioon, Amjad; Koivisto, Tomi

    2016-12-01

    If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations. This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation. The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be |B|≲0.06. The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations. In the large occupation number limit, a distinctive prediction is a modulation of the non-gaussianity around a mean value depending on the angle that short and long wavelength modes make with the preferred direction. The maximal variations with respect to the mean value occur for the configurations which are coplanar with the preferred direction and the amplitude of the non-gaussianity increases (decreases) for the short wavelength modes aligned with (perpendicular to) the preferred direction. For a high scale model of inflation with maximally pumped up isotropic occupation and ϵ≃0.01 the difference between these two configurations is about 0.27, which could be detectable in the future. For purely anisotropic particle creation, the non-Gaussianity can be larger and its anisotropic feature very sharp. The non-gaussianity can then reach f{sub NL}∼30 in the preferred direction while disappearing from the correlations in the orthogonal plane.

  4. Anisotropic non-gaussianity from rotational symmetry breaking excited initial states

    NASA Astrophysics Data System (ADS)

    Ashoorioon, Amjad; Casadio, Roberto; Koivisto, Tomi

    2016-12-01

    If the initial quantum state of the primordial perturbations broke rotational invariance, that would be seen as a statistical anisotropy in the angular correlations of the cosmic microwave background radiation (CMBR) temperature fluctuations. This can be described by a general parameterisation of the initial conditions that takes into account the possible direction-dependence of both the amplitude and the phase of particle creation during inflation. The leading effect in the CMBR two-point function is typically a quadrupole modulation, whose coefficient is analytically constrained here to be |B| lesssim 0.06. The CMBR three-point function then acquires enhanced non-gaussianity, especially for the local configurations. In the large occupation number limit, a distinctive prediction is a modulation of the non-gaussianity around a mean value depending on the angle that short and long wavelength modes make with the preferred direction. The maximal variations with respect to the mean value occur for the configurations which are coplanar with the preferred direction and the amplitude of the non-gaussianity increases (decreases) for the short wavelength modes aligned with (perpendicular to) the preferred direction. For a high scale model of inflation with maximally pumped up isotropic occupation and epsilonsimeq 0.01 the difference between these two configurations is about 0.27, which could be detectable in the future. For purely anisotropic particle creation, the non-Gaussianity can be larger and its anisotropic feature very sharp. The non-gaussianity can then reach 0fNL ~ 3 in the preferred direction while disappearing from the correlations in the orthogonal plane.

  5. Consequences of a strong phase transition in the dense matter equation of state for the rotational evolution of neutron stars

    NASA Astrophysics Data System (ADS)

    Bejger, M.; Blaschke, D.; Haensel, P.; Zdunik, J. L.; Fortin, M.

    2017-03-01

    Aims: We explore the implications of a strong first-order phase transition region in the dense matter equation of state in the interiors of rotating neutron stars, and the resulting creation of two disjoint families of neutron-star configurations (the so-called high-mass twins). Methods: We numerically obtained rotating, axisymmetric, and stationary stellar configurations in the framework of general relativity, and studied their global parameters and stability. Results: The instability induced by the equation of state divides stable neutron star configurations into two disjoint families: neutron stars (second family) and hybrid stars (third family), with an overlapping region in mass, the high-mass twin-star region. These two regions are divided by an instability strip. Its existence has interesting astrophysical consequences for rotating neutron stars. We note that it provides a natural explanation for the rotational frequency cutoff in the observed distribution of neutron star spins, and for the apparent lack of back-bending in pulsar timing. It also straightforwardly enables a substantial energy release in a mini-collapse to another neutron-star configuration (core quake), or to a black hole.

  6. Calculating rovibrationally excited states of H2D+ and HD2+ by combination of fixed node and multi-state rotational diffusion Monte Carlo

    NASA Astrophysics Data System (ADS)

    Ford, Jason E.; McCoy, Anne B.

    2016-02-01

    In this work the efficacy of a combined approach for capturing rovibrational coupling is investigated. Specifically, the multi-state rotational DMC method is used in combination with fixed-node DMC in a study of the rotation vibration energy levels of H2D+ and HD2+. Analysis of the results of these calculations shows very good agreement between the calculated energies and previously reported values. Where differences are found, they can be attributed to Coriolis couplings, which are large in these ions and which are not fully accounted for in this approach.

  7. Titan’s internal structure inferred from its gravity field, shape, and rotation state

    NASA Astrophysics Data System (ADS)

    Baland, Rose-Marie; Tobie, Gabriel; Lefèvre, Axel; Van Hoolst, Tim

    2014-07-01

    Several quantities measured by the Cassini-Huygens mission provide insight into the interior of Titan: the second-degree gravity field coefficients, the shape, the tidal Love number, the electric field, and the orientation of its rotation axis. The measured obliquity and tides, as well as the electric field, are evidence for the presence of an internal global ocean beneath the icy shell of Titan. Here we use these different observations together to constrain the density profile assuming a four-layer interior model (ice I shell, liquid water ocean, high pressure ice mantle, and rock core). Even though the observed second degree gravity field is consistent with the hydrostatic relation J2=10C22/3, which is a necessary but not sufficient condition for a synchronous satellite to be in hydrostatic equilibrium, the observed shape of the surface as well as the non-zero degree-three gravity signal indicate some departure from hydrostaticity. Therefore, we do not restrain our range of assumed density profiles to those corresponding to the hydrostatic value of the moment of inertia (0.34). From a range of density profiles consistent with the radius and mass of the satellite, we compute the obliquity of the Cassini state and the tidal Love number k2. The obliquity is computed from a Cassini state model for a satellite with an internal liquid layer, each layer having an ellipsoidal shape consistent with the measured surface shape and gravity field. The observed (nearly hydrostatic) gravity field is obtained by an additional deflection of the ocean-ice I shell interface, assuming that the layers have uniform densities. We show that the measured obliquity can be reproduced only for internal models with a dense ocean (between 1275 and 1350 kg m-3) above a differentiated interior with a full separation of rock and ice. We obtain normalized moments of inertia between 0.31 and 0.33, significantly lower than the expected hydrostatic value (0.34). Evolutionary mechanisms leading to a

  8. Preliminary solution for the shape and rotational state of the nucleus of comet 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Lamy, P.; Jorda, L.; Kaasalainen, M.; Hviid, S.; Faury, G.; Toth, I.; Groussin, O.

    2014-07-01

    In preparation of ESA's ROSETTA mission to comet 67P/Churyumov-Gerasimenko, solutions for the shape and rotational state of its nucleus have been published based on observation with the Hubble and Spitzer space telescopes as well as ground-based observations (Lamy et al. 2006, 2007, 2008; Lowry et al. 2012). Following the wake-up of the Rosetta spacecraft in January 2014 and the successful commissioning of the OSIRIS camera system in March, a first lightcurve of the inactive nucleus has been obtained on 23 March 2014 with the OSIRIS Narrow Angle Camera (NAC). Further lightcurves will be acquired in the forthcoming months. We will present an updated solution for the shape and rotational state based on these data sets as of end of June 2014 combined with past Hubble and Spitzer space telescopes as well as ground-based observations using the technique of lightcurve inversion.

  9. Positioning configurations with the lowest GDOP and their classification

    NASA Astrophysics Data System (ADS)

    Xue, Shuqiang; Yang, Yuanxi

    2015-01-01

    The positioning configuration optimization is a basic problem in surveying, and the geometric dilution of precision (GDOP) is a key index to handle this problem. Simplex graphs as regular polygons and regular polyhedrons are the well-known configurations with the lowest GDOP. However, it has been proved that there are at most five kinds of regular polyhedrons. We analytically solve the GDOP minimization problem with arbitrary observational freedom to extend the current knowledge. The configuration optimization framework established is composed of the algebraic and geometric operators (including combination, reflection, collinear mapping, projection and three kinds of equivalence relations), basic properties to GDOP minimization (including continuity, combination invariant, reflection invariant, rotation invariant and collinear invariant) and the lowest GDOP configurations (including cones, regular polygons, regular polyhedrons, Descartes configuration, helical configuration and generalized Walker configuration, and their reflections and combinations). GDOP minimization criterion and D-maximization criterion both reduce to the same criterion matrices that the optimization becomes the problem for solving an underdetermined quadratic equation system. Making use of the concepts for solving underdetermined linear equation system, the concepts of base configuration (single classification) and general configuration (combined classification) are applied to the GDOP minimization to analytically solve the quadratic equation system. Firstly, the problems are divided into two subproblems by two kinds of GDOP to reveal the impact of the clock-offset on the configuration optimization, and it shows that the symmetry and uniformity play a key role in identifying the systematic errors. Then, the solution of the GDOP minimization is classified by the number of symmetry axes, that the base configurations with at least one symmetry axis and the general configurations without symmetry

  10. Monte Carlo trajectory calculation of state-to-state cross sections for vibrational-rotational-translational energy transfer in Ar-H/sub 2/ collisions

    SciTech Connect

    Blais, N.C.; Truhlar, D.G.

    1982-01-01

    We have carried out quasiclassical trajectory calculations of the energy transfer cross sections for five initial states of H/sub 2/ ((v,j) = (0,6), (0,18), (2,18), (4,6), and (2,18)) in collisions with Ar at a fixed total energy of 1.0 eV (with respect to the energy of Ar + 2H). The first of these states has an internal excitation energy that is 7% of the dissociation energy D/sub 0/, and the other four states have internal excitation energies from 45 to 63% of D/sub 0/. The calculations are based on the most accurate available potential energy surface. The results are presented as tables of state-to-state cross sections and as contour maps of these cross sections as functions of the final quantum numbers. For the four highly excited initial states these maps show large changes of v and j, extensive vibrational-rotational energy transfer, and the population of 57-142 final states. The total vibrational-change cross sections for these states are 3.7 to 7.4 times larger than for the (0,6) state. No simple functional form gives a quantitative fit to all the pure-rotational-translational energy-transfer cross sections, and a quantitative fit to all the cross sections poses an even more severe theoretical challenge.

  11. Lowest ^{2}S Electronic Excitations of the Boron Atom.

    PubMed

    Bubin, Sergiy; Adamowicz, Ludwik

    2017-01-27

    A theoretical ab initio approach for calculating bound states of small atoms is developed and implemented. The approach is based on finite-nuclear-mass [non-Born-Oppenheimer (non-BO)] nonrelativistic variational calculations performed with all-particle explicitly correlated Gaussian functions and includes the leading relativistic and quantum electrodynamics energy corrections determined using the non-BO wave functions. The approach is applied to determine the total and transition energies for the lowest four ^{2}S electronic excitations of the boron atom. The transition energies agree with the available experimental values within 0.2-0.3  cm^{-1}. Previously, such accuracy was achieved for three- and four-electron systems.

  12. Lowest 2S Electronic Excitations of the Boron Atom

    NASA Astrophysics Data System (ADS)

    Bubin, Sergiy; Adamowicz, Ludwik

    2017-01-01

    A theoretical ab initio approach for calculating bound states of small atoms is developed and implemented. The approach is based on finite-nuclear-mass [non-Born-Oppenheimer (non-BO)] nonrelativistic variational calculations performed with all-particle explicitly correlated Gaussian functions and includes the leading relativistic and quantum electrodynamics energy corrections determined using the non-BO wave functions. The approach is applied to determine the total and transition energies for the lowest four 2S electronic excitations of the boron atom. The transition energies agree with the available experimental values within 0.2 - 0.3 cm-1 . Previously, such accuracy was achieved for three- and four-electron systems.

  13. Theoretical investigation of the lowest-lying electronic structure of LuI molecules

    NASA Astrophysics Data System (ADS)

    Assaf, J.; Taher, F.; Magnier, S.

    2014-01-01

    CASSCF/MRCI calculations using Effective Core Potential (ECP) basis sets for both Lu and I atoms, have been performed for the first 22 electronic states in the representation 2s+1Λ(±) for the LuI molecule. This investigation included the corresponding 43 molecular states in the representation Ω(±) when taking the spin-orbit coupling (SOC) in consideration. Calculated potential energy curves (PECs) have been displayed. Spectroscopic constants Te, ωe, ωeχe, Be and the internuclear distance Re have been calculated for the ground state and for the low-lying electronic states situated below 40,410 cm-1 and for their corresponding components with SOC. The transition dipolar moments between states have been given at the minimum position Re = 2.75 Å of the ground state X1Σ+. The calculated set of singlet and triplet states provides a theoretical prediction for more than 19 yet unobserved electronic states.

  14. The impact of vertical shear on the sensitivity of tropical cyclogenesis to environmental rotation and thermodynamic state

    DOE PAGES

    Zhou, Wenyu

    2015-11-19

    Here, the impact of vertical wind shear on the sensitivity of tropical cyclogenesis to environmental rotation and thermodynamic state is investigated through idealized cloud-resolving simulations of the intensification of an incipient vortex. With vertical shear, tropical cyclones intensify faster with a higher Coriolis parameter, f, irrespective of the environmental thermodynamic state. The vertical shear develops a vertically tilted vortex, which undergoes a precession process with the midlevel vortices rotating cyclonically around the surface center. With a higher f, the midlevel vortices are able to rotate continuously against the vertical shear, leading to the realignment of the tilted vortex and rapidmore » intensification. With a lower f, the rotation is too slow such that the midlevel vortices are advected away from the surface center and the intensification is suppressed. The parameter, Χb, measuring the effect from the low-entropy downdraft air on the boundary layer entropy, is found to be a good indicator of the environmental thermodynamic favorability for tropical cyclogenesis in vertical shear. Without vertical shear, tropical cyclones are found to intensify faster with a lower f by previous studies. We show this dependency on f is sensitive to the environmental thermodynamic state. The thermodynamical favorability for convection can be measured by Χm, which estimates the time it takes for surface fluxes to moisten the midtroposphere. A smaller Χm not only leads to a faster intensification due to a shorter period for moist preconditioning of the inner region but also neutralizes the faster intensification with a lower f due to enhanced peripheral convection.« less

  15. Einstein A-Coefficients for Rotational Transitions in the NU/3 Vibrationally Excited State of SIC2

    NASA Astrophysics Data System (ADS)

    Chandra, S.; Sahu, A.

    1993-05-01

    Einstein A-values for the electric dipole transitions between rotational levels up to 55 cm-1 in the ν3 vibrationally excited state of SiC2 are calculated. The coefficients are used to compute the mean radiative lifetimes of the levels. Scientists are optimistic with respect to the detection of SiC2 in the ν3 vibrationally excited state in the envelope of the star IRC 10216. The Einstein A-values can be used for analysing the spectra.

  16. How Are Short Rotations Woody Crops Affected By Institutional Factors in the Southern United States?

    Treesearch

    Donald L. Grebner; Rodney L. Busby

    2004-01-01

    Short-rotation woody crops (SRWC) produce a variety of forest products useful to consumers such as pulp, energy biomass, and solid wood. The establishment and management of these crops before conversion into manufactured products are affected by several institutional factors. The first objective of this study was to identify and document institutional structures and...

  17. The Rotational Spectrum of Chloryl Chloride, CICIO(sub 2), in its Ground Vibrational State

    NASA Technical Reports Server (NTRS)

    Cohen, E.; Muller, H.; Christen, D.

    1999-01-01

    Rotational spectra of the four main isotopomers of CICIO(sub 2) which together span the quantum numbers 10 < or = J < or = 77 and 0 < or = K(sub a) < or = 34 have been studied in selected regions between 10 and 417 GHz.

  18. Role of irregular otolith afferents in the steady-state nystagmus during off-vertical axis rotation

    NASA Technical Reports Server (NTRS)

    Angelaki, D. E.; Perachio, A. A.; Mustari, M. J.; Strunk, C. L.

    1992-01-01

    1. During constant velocity off-vertical axis rotations (OVAR) in the dark a compensatory ocular nystagmus is present throughout rotation despite the lack of a maintained signal from the semicircular canals. Lesion experiments and canal plugging have attributed the steady-state ocular nystagmus during OVAR to inputs from the otolith organs and have demonstrated that it depends on an intact velocity storage mechanism. 2. To test whether irregularly discharging otolith afferents play a crucial role in the generation of the steady-state eye nystagmus during OVAR, we have used anodal (inhibitory) currents bilaterally to selectively and reversibly block irregular vestibular afferent discharge. During delivery of DC anodal currents (100 microA) bilaterally to both ears, the slow phase eye velocity of the steady-state nystagmus during OVAR was reduced or completely abolished. The disruption of the steady-state nystagmus was transient and lasted only during the period of galvanic stimulation. 3. To distinguish a possible effect of ablation of the background discharge rates of irregular vestibular afferents on the velocity storage mechanism from specific contributions of the dynamic responses from irregular otolith afferents to the circuit responsible for the generation of the steady-state nystagmus, bilateral DC anodal galvanic stimulation was applied during optokinetic nystagmus (OKN) and optokinetic afternystagmus (OKAN). No change in OKN and OKAN was observed.(ABSTRACT TRUNCATED AT 250 WORDS).

  19. Analysis of the Rotational Spectrum of HDO in its v_2 = 0 and 1 Vibrational States up to 2.8 THz

    NASA Astrophysics Data System (ADS)

    Müller, Holger S. P.; Brünken, S.; Endres, C. P.; Lewen, F.; Pearson, J. C.; Yu, S.; Drouin, B. J.; Mäder, H.

    2011-06-01

    The rotational and rovibrational spectra of H_2O and its isotopologs, including HDO, are of great importance for atmospheric chemistry, astrophysics, and basic sciences. We recorded rotational spectra of HDO in the ground and first excited bending state from the microwave region up to 2.8 THz. Several spectrometers were employed in Kiel, Köln, and Pasadena. An up-to-date combined analysis with rovibrational data was presented, footnote{S. Brünken, PhD thesis, Universität zu Köln, July 2005, Cuvillier Verlag, Göttingen} in which a Hamiltonian based on Euler functions was used to overcome convergence difficulties of the conventional Watson Hamiltonian. The model had been employed previously, e. g., in a related analysis of D_2O spectra with v_2 ≤ 1. Recently, many more data have been obtained in Köln as well as in Pasadena. Including multiple measurements, these add up to about 230 and 100 new transition frequencies in v_2 = 0 and 1, respectively, reaching J = 17/13 and K_a = 9/5. In addition, a critically evaluated compilation of IR data was published very recently. Difficulties in reproducing the data within experimental uncertainties prompted a reanalysis of the data starting at small quantum numbers and extending the data set in small portions. At lower quantum numbers, difficulties were due to, e. g., few typographical errors and misassignments. At higher quantum numbers, interactions between v_2 = 0 and 1 as well as between these and higher states (e. g. v_2 = 2/v_1 = 1, which interact through Fermi resonance) are more important. The limitation of the present analysis to the lowest two vibrational states affords some transitions to be excluded from the analysis and causes a truncation of the data set at some values of J and K_a. S. Brünken, PhD thesis, Universität zu Köln, July 2005, Cuvillier Verlag, Göttingen H. M. Pickett, J. C. Pearson, C. P. Miller, J. Mol. Spectrosc. 233 (2005) 174. J. Tennyson et al., J. Quant. Spectrosc. Radiat. Transfer 111

  20. Rotationally resolved IR-diode laser studies of ground-state CO2 excited by collisions with vibrationally excited pyridine.

    PubMed

    Johnson, Jeremy A; Kim, Kilyoung; Mayhew, Maurine; Mitchell, Deborah G; Sevy, Eric T

    2008-03-27

    Relaxation of highly vibrationally excited pyridine (C5NH5) by collisions with carbon dioxide has been investigated using diode laser transient absorption spectroscopy. Vibrationally hot pyridine (E' = 40,660 cm(-1)) was prepared by 248 nm excimer laser excitation followed by rapid radiationless relaxation to the ground electronic state. Pyridine then collides with CO2, populating the high rotational CO2 states with large amounts of translational energy. The CO2 nascent rotational population distribution of the high-J (J = 58-80) tail of the 00(0)0 state was probed at short times following the excimer laser pulse to measure rate constants and probabilities for collisions populating these CO2 rotational states. Doppler spectroscopy was used to measure the CO2 recoil velocity distribution for J = 58-80 of the 00(0)0 state. The energy-transfer distribution function, P(E,E'), from E' - E approximately 1300-7000 cm(-1) was obtained by re-sorting the state-indexed energy-transfer probabilities as a function of DeltaE. P(E,E') is fit to an exponential or biexponential function to determine the average energy transferred in a single collision between pyridine and CO2. Also obtained are fit parameters that can be compared to previously studied systems (pyrazine, C6F6, methylpyrazine, and pyrimidine/CO2). Although the rotational and translational temperatures that describe pyridine/CO2 energy transfer are similar to previous systems, the energy-transfer probabilities are much smaller. P(E,E') fit parameters for pyridine/CO2 and the four previously studied systems are compared to various donor molecular properties. Finally, P(E,E') is analyzed in the context of two models, one indicating that P(E,E') shape is primarily determined by the low-frequency out-of-plane donor vibrational modes, and the other that indicates that P(E,E') shape can be determined from how the donor molecule final density of states changes with DeltaE.

  1. A Multi-State Single-Molecule Switch Actuated by Rotation of an Encapsulated Cluster within a Fullerene Cage

    SciTech Connect

    Huang, Tian; Zhao, Jin; Feng, Min; Popov, Alexey A.; Yang, Shangfeng; Dunsch, Lothar; Petek, Hrvoje

    2012-11-12

    We demonstrate a single-molecule switch based on tunneling electron-driven rotation of a triangular Sc₃N cluster within an icosahedral C 80 fullerene cage among three pairs of enantiomorphic configura-tions. Scanning tunneling microscopy imaging of switching within single molecules and electronic structure theory identify the conformational isomers and their isomerization pathways. Bias-dependent actionspectra and modeling identify the antisymmetric stretch vibration of Sc 3N cluster to be the gateway for energy transfer from the tunneling electrons to the cluster rotation. Hierarchical switching of conductivity through the internal cluster motion among multiple stationary states while maintaining a constant shape, is advantageous for the integration of endohedral fullerene-based single-molecule memory and logic devices into parallel molecular computing arc.

  2. Collision energy dependence of state-to-state differential cross sections for rotationally inelastic scattering of H2O by He.

    PubMed

    Sarma, Gautam; Saha, Ashim Kumar; Bishwakarma, Chandan Kumar; Scheidsbach, Roy; Yang, Chung-Hsin; Parker, David; Wiesenfeld, Laurent; Buck, Udo; Mavridis, Lazaros; Marinakis, Sarantos

    2017-02-08

    The inelastic scattering of H2O by He as a function of collision energy in the range 381 cm(-1) to 763 cm(-1) at an energy interval of approximately 100 cm(-1) has been investigated in a crossed beam experiment using velocity map imaging. Change in collision energy was achieved by varying the collision angle between the H2O and He beam. We measured the state-to-state differential cross section (DCS) of scattered H2O products for the final rotational states JKaKc = 110, 111, 221 and 414. Rotational excitation of H2O is probed by (2 + 1) resonance enhanced multiphoton ionization (REMPI) spectroscopy. DCS measurements over a wide range of collision energies allowed us to probe the H2O-He potential energy surface (PES) with greater detail than in previous work. We found that a classical approximation of rotational rainbows can predict the collision energy dependence of the DCS. Close-coupling quantum mechanical calculations were used to produce DCS and partial cross sections. The forward-backward ratio (FBR), is introduced here to compare the experimental and theoretical DCS. Both theory and experiments suggest that an increase in the collision energy is accompanied with more forward scattering.

  3. The determination of Mercury's gravity field and rotational state with the mission BepiColombo

    NASA Astrophysics Data System (ADS)

    Iess, L.; Asmar, S. W.; Milani, A.; Tortora, P.; Iafolla, V.

    Gravity field and rotational state provide accurate constraints to geophysical models of planetary interiors and have been therefore a major source of information on the internal structure of solar system bodies. Their determination is particularly important for Mercury, whose interior is the least known among terrestrial planets. Today, planetary gravity fields are best investigated by means of microwave Doppler tracking of orbiting spacecraft. In order to attain precise measurements the radio link (involving a carrier transmitted from ground to the spacecraft and retransmitted back to ground) must preserve the highest phase stability and coherence at each intervening stage. Electronic noise from ground and onboard instrumentation must be minimized and propagation noise (due to plasma and troposphere) must be kept to a minimum. This is especially important for phase instabilities induced by interplanetary plasma and solar corona, which have been the main limitation in past gravity experiments with planetary probes. Both forthcoming space missions to Mercury (NASA's Messenger and ESA's Bepi- Colombo) host radio science investigations devoted to geodesy and geophysics. While Messenger's experiment exploits the onboard telecommunication system, based upon a X-band radio link (7.1-8.4 GHz), the experiment MORE (Mercury Orbiter Radioscience Experiment) of BepiColombo makes use of a Ka-band radio link (32-34 GHz) enabled by dedicated onboard and ground hardware. The use of a Ka-band link in combination with the standard telecommunication system allows a complete cancellation of the plasma noise and two-way range rate measurements as accurate as 3 micron/s over time scales of 1000 s, independently of the solar elongation angle. The radio instrumentation includes also a wide-band ranging system (WBRS, using a 20 MHz tone) with a target two-way accuracy of 20 cm. The ranging system will be used to determine Mercury's orbit in the solar system, carrying out accurate tests

  4. Hydrogen isotope separation in carbon nanotubes: calculation of coupled rotational and translational States at high densities.

    PubMed

    Garberoglio, Giovanni; Johnson, J Karl

    2010-03-23

    The effect of the quantized rotational degrees of freedom of hydrogen on the adsorption and sieving properties in carbon nanotubes is studied using computer simulations. We have developed a highly efficient multiple timestep algorithm for hybrid Monte Carlo sampling of quantized rotor configurations and extended the grand canonical Boltzmann bias method to rigid linear molecules. These new computational tools allow us to calculate accurately the quantum sieving selectivities for cases of extreme two-dimensional confinement as a function of pressure. The para-T2/para-H2 selectivity at 20 K is analyzed as a function of the tube diameter and the density of adsorbed hydrogen. Extraordinarily high selectivities, up to 2.6 x 10(8), are observed in the narrowest nanotube. The quantized nature of the rotational degrees of freedom is found to dramatically affect adsorption and selectivity for hydrogen isotopes adsorbed in very narrow nanotubes. The T2/H2 zero-pressure selectivity increases from 2.4 x 10(4) to 1.7 x 10(8) in the (3,6) nanotube at 20 K when quantum rotations are accounted for. The isotopic selectivity is found to increase with pressure, tending to a constant value at saturation. A simplified mean-field model is used to discuss the origin of this behavior.

  5. Excited Rotational States in Doped {4} He Clusters: a Diffusion Monte Carlo Analysis

    NASA Astrophysics Data System (ADS)

    Coccia, Emanuele

    2017-03-01

    We report an extension of diffusion Monte Carlo (DMC) to the calculation of the molecular rotational energies by means of the generalized, symmetry-adapted, imaginary-time correlation functions (SAITCFs) originally introduced in the reptation quantum Monte Carlo (RQMC) framework (Škrbić in J Phys Chem A 111:12749, 2007). We studied the a-type and b-type rotational lines of the CO(4 He)N clusters with N= 1-8 that correlate, in the dimer limit, with the end-over-end and free-rotor transitions. We compare the SAITCF-DMC results with accurate DVR (for the dimer case), RQMC and other DMC data, and with reference experimental findings (Surin in Phys Rev Lett 101:233401, 2008). A good agreement is generally found, but a systematic underestimation of the SAITCF-DMC rotational energies of the b-type series is observed. Sources of inaccuracy in our theoretical approach and in the computational protocol are discussed and analyzed in detail.

  6. Rotational state dependence of rate constants for the reaction of ions with asymmetric top molecules at very low temperatures: application to the N+/H2O system

    NASA Astrophysics Data System (ADS)

    Dubernet, M. L.; McCarroll, R.

    1990-12-01

    The adiabatic rotational state method is applied to the study of reactions between ions and polar asymmetric top molecules at very low temperatures. Detailed results of the calculated rate coefficients for the reaction of N+ with H2O are presented. A strong dependence of the rate coefficients on the initial rotational state is observed at low temperatures. In the case of a thermal distribution of rotational states, where the rate constants are summed over a Boltzman distribution, the replacement of the asymmetric top by an average symmetric top, which leads to a considerable simplification of the calculations, appears to be satisfactory. On the other hand, for a non thermal distribution, no such simplifying assumption can be made. In particular, the rate coefficient for a specific initial rotational state is quite sensitive to the orientation of the dipole moment.

  7. Coupled bending-torsion steady-state response of pretwisted, nonuniform rotating beams using a transfer-matrix method

    NASA Technical Reports Server (NTRS)

    Gray, Carl E., Jr.

    1988-01-01

    Using the Newtonian method, the equations of motion are developed for the coupled bending-torsion steady-state response of beams rotating at constant angular velocity in a fixed plane. The resulting equations are valid to first order strain-displacement relationships for a long beam with all other nonlinear terms retained. In addition, the equations are valid for beams with the mass centroidal axis offset (eccentric) from the elastic axis, nonuniform mass and section properties, and variable twist. The solution of these coupled, nonlinear, nonhomogeneous, differential equations is obtained by modifying a Hunter linear second-order transfer-matrix solution procedure to solve the nonlinear differential equations and programming the solution for a desk-top personal computer. The modified transfer-matrix method was verified by comparing the solution for a rotating beam with a geometric, nonlinear, finite-element computer code solution; and for a simple rotating beam problem, the modified method demonstrated a significant advantage over the finite-element solution in accuracy, ease of solution, and actual computer processing time required to effect a solution.

  8. State-dependent rotational diffusion of tetracene in n-alkanes. Evidence for a dominant energy relaxation pathway.

    PubMed

    Mize, Hannah E; Blanchard, G J

    2013-12-19

    We have investigated the rotational diffusion of tetracene in the n-alkanes octane through hexadecane. Emission from the S1 state was monitored following excitation to the S1 state or the S2 state. Our data show that fast, non-radiative relaxation from S2 to S1 gives rise to local heating in the immediate vicinity of the chromophore. This local heating effect exhibits a solvent aliphatic chain length dependence for solvents C11 and longer, where solvents with an even number of carbons behave differently than those with an odd number of carbons. These data shed light on the possible origin(s) of odd-even effects in n-alkanes and suggest that a dominant intermolecular relaxation pathway for excess vibrational energy involves the S1 chromophore ring breathing mode (ca. 1383 cm(-1)) and the solvent terminal methyl group rocking mode (1375 cm(-1)).

  9. The rotational spectra of the ground and first excited bending states of deuterium isocyanide, DNC, up to 2 THz

    NASA Astrophysics Data System (ADS)

    Brünken, S.; Müller, H. S. P.; Thorwirth, S.; Lewen, F.; Winnewisser, G.

    2006-01-01

    The pure rotational spectrum of deuterium isocyanide (DNC) was recorded in the frequency range from approximately 680 to 1985 GHz. Twenty-one new transitions in the vibrational ground and first excited bending states (01e,f 0) have been assigned, namely R-branch transitions from J=9-8 to 25-24. In a least squares analysis of these new transition frequencies together with previously reported millimeter-wave data, spectroscopic parameters up to sextic order could be derived with high precision for both states. Furthermore, the l-type doubling constant q and its centrifugal distortion terms qJ and qJJ were obtained for the first excited bending state.

  10. Classification of the ground states and topological defects in a rotating two-component Bose-Einstein condensate

    SciTech Connect

    Mason, Peter; Aftalion, Amandine

    2011-09-15

    We classify the ground states and topological defects of a rotating two-component condensate when varying several parameters: the intracomponent coupling strengths, the intercomponent coupling strength, and the particle numbers. No restriction is placed on the masses or trapping frequencies of the individual components. We present numerical phase diagrams which show the boundaries between the regions of coexistence, spatial separation, and symmetry breaking. Defects such as triangular coreless vortex lattices, square coreless vortex lattices, and giant skyrmions are classified. Various aspects of the phase diagrams are analytically justified thanks to a nonlinear {sigma} model that describes the condensate in terms of the total density and a pseudo-spin representation.

  11. Dipolar Assisted Assignment Protocol (DAAP) for MAS solid-state NMR of rotationally aligned membrane proteins in phospholipid bilayers

    NASA Astrophysics Data System (ADS)

    Das, Bibhuti B.; Zhang, Hua; Opella, Stanley J.

    2014-05-01

    A method for making resonance assignments in magic angle spinning solid-state NMR spectra of membrane proteins that utilizes the range of heteronuclear dipolar coupling frequencies in combination with conventional chemical shift based assignment methods is demonstrated. The Dipolar Assisted Assignment Protocol (DAAP) takes advantage of the rotational alignment of the membrane proteins in liquid crystalline phospholipid bilayers. Improved resolution is obtained by combining the magnetically inequivalent heteronuclear dipolar frequencies with isotropic chemical shift frequencies. Spectra with both dipolar and chemical shift frequency axes assist with resonance assignments. DAAP can be readily extended to three- and four-dimensional experiments and to include both backbone and side chain sites in proteins.

  12. Ab initio ground-state potential energy function and vibration-rotation energy levels of imidogen, NH.

    PubMed

    Koput, Jacek

    2015-06-30

    The accurate ground-state potential energy function of imidogen, NH, has been determined from ab initio calculations using the multireference averaged coupled-pair functional (MR-ACPF) method in conjunction with the correlation-consistent core-valence basis sets up to octuple-zeta quality. The importance of several effects, including electron correlation beyond the MR-ACPF level of approximation, the scalar relativistic, adiabatic, and nonadiabatic corrections were discussed. Along with the large one-particle basis set, all of these effects were found to be crucial to attain "spectroscopic" accuracy of the theoretical predictions of vibration-rotation energy levels of NH.

  13. Rotating night-shift work and lung cancer risk among female nurses in the United States.

    PubMed

    Schernhammer, Eva S; Feskanich, Diane; Liang, Geyu; Han, Jiali

    2013-11-01

    The risk of lung cancer among night-shift workers is unknown. Over 20 years of follow-up (1988-2008), we documented 1,455 incident lung cancers among 78,612 women in the Nurses' Health Study. To examine the relationship between rotating night-shift work and lung cancer risk, we used multivariate Cox proportional hazard models adjusted for detailed smoking characteristics and other risk factors. We observed a 28% increased risk of lung cancer among women with 15 or more years spent working rotating night shifts (multivariate relative risk (RR) = 1.28, 95% confidence interval (CI): 1.07, 1.53; Ptrend = 0.03) compared with women who did not work any night shifts. This association was strongest for small-cell lung carcinomas (multivariate RR = 1.56, 95% CI: 0.99, 2.47; Ptrend = 0.03) and was not observed for adenocarcinomas of the lung (multivariate RR = 0.91, 95% CI: 0.67, 1.24; Ptrend = 0.40). Further, the increased risk associated with 15 or more years of rotating night-shift work was limited to current smokers (RR = 1.61, 95% CI: 1.21, 2.13; Ptrend < 0.001), with no association seen in nonsmokers (Pinteraction = 0.03). These results suggest that there are modestly increased risks of lung cancer associated with extended periods of night-shift work among smokers but not among nonsmokers. Though it is possible that this observation was residually confounded by smoking, our findings could also provide evidence of circadian disruption as a "second hit" in the etiology of smoking-related lung tumors.

  14. Flow patterns in linear state of Rayleigh-Bénard convection in a rotating nanofluid layer

    NASA Astrophysics Data System (ADS)

    Agarwal, Shilpi; Bhadauria, B. S.

    2013-10-01

    In this paper, we study the flow patterns of a rotating, horizontal layer of a Newtonian nanofluid. The nanofluid layer incorporates the effect of Brownian motion along with thermophoresis. In order to find the expressions for streamlines, isotherms, and iso-nanohalines, a minimal representation of the truncated Fourier series of two terms, has been used. The results obtained imply that the magnitude of the streamlines, and the contours of the isotherms and the iso-nanohalines, turn flatter and concentrated near the boundaries for large value of Ra cr , indicating a delay in the onset of convection.

  15. Semiclassical model for the distribution of final polar angles and m‧ states in rotationally inelastic collisions

    NASA Astrophysics Data System (ADS)

    Price, T. J.; Towne, A. C.; Talbi, D.; Hickman, A. P.

    2016-02-01

    Using the venerable vector model, we develop an expression for the change in the polar angle of the angular momentum of a rotator caused by collisions in a cell-type experiment. For an initial j precessing with polar angle θ, and a given distribution of 'tipping angles', we derive the distribution of final polar angles θ‧. Final m‧ levels are also determined. The results agree well with exact quantum calculations for thermal collisions of He or Ar with NaK. We also identify a special case where the distribution of θ‧ has a simple Lorentzian form.

  16. Bose-Einstein condensates in strong electric fields: Effective gauge potentials and rotating states

    SciTech Connect

    Kailasvuori, J.M.; Hansson, T.H.; Kavoulakis, G.M.

    2002-11-01

    Magnetically trapped atoms in Bose-Einstein condensates are spin polarized. Since the magnetic field is inhomogeneous, the atoms acquire Berry phases of the Aharonov-Bohm type during adiabatic motion. In the presence of an electric field, there is an additional Aharonov-Casher effect. Taking into account the limitations on the strength of the electric fields due to the polarizability of the atoms, we investigate the extent to which these effects can be used to induce rotation in a Bose-Einstein condensate.

  17. Lowest cost due to highest productivity and highest quality

    NASA Astrophysics Data System (ADS)

    Wenk, Daniel

    2003-03-01

    Since global purchasing in the automotive industry has been taken up all around the world there is one main key factor that makes a TB-supplier today successful: Producing highest quality at lowest cost. The fact that Tailored Blanks, which today may reach up to 1/3 of a car body weight, are purchased on the free market but from different steel suppliers, especially in Europe and NAFTA, the philosophy on OEM side has been changing gradually towards tough evaluation criteria. "No risk at the stamping side" calls for top quality Tailored- or Tubular Blank products. Outsourcing Tailored Blanks has been starting in Japan but up to now without any quality request from the OEM side like ISO 13919-1B (welding quality standard in Europe and USA). Increased competition will automatically push the quality level and the ongoing approach to combine high strength steel with Tailored- and Tubular Blanks will ask for even more reliable system concepts which enables to weld narrow seams at highest speed. Beside producing quality, which is the key to reduce one of the most important cost driver "material scrap," in-line quality systems with true and reliable evaluation is going to be a "must" on all weld systems. Traceability of all process related data submitted to interfaces according to customer request in combination with ghost-shift-operation of TB systems are tomorrow's state-of-the-art solutions of Tailored Blank-facilities.

  18. Analysis of the Rotational Structure of ˜{B}^2A' ← ˜{X}^2A' Transition of Isopropoxy Radical: Isolated State vs. Coupled States Model

    NASA Astrophysics Data System (ADS)

    Melnik, Dmitry G.; Miller, Terry A.; Liu, Jinjun

    2013-06-01

    Isopropoxy radicals are reactive intermediates in atmospheric and combustion chemistry. From the theoretical point of view, they represent an extreme case of ``isotopically'' substituted methoxy radicals with two methyl groups playing the role of heavy hydrogen isotopes. Previously the rotationally resolved spectra of ˜{B}^2A' ← ˜{X}^2A' electronic transition were successfully analyzed using a simple effective rotational Hamiltonian of the isolated ˜{X} and ˜{B} states. However, a number of the experimentally determined parameters appeared dramatically inconsistent with the quantum chemistry calculations and theoretical predictions based on the symmetry arguments. Recently, we analyzed these spectra using a coupled two state model, which explicitly includes interactions between the ground ˜{X}^2A' state and low-lying excited ˜{A}^2A^'' state. In this presentation we will discuss the results of this analysis and compare the parameters of both models and their physical significance. D. G. Melnik, T. A. Miller and J. Liu, TI15, 67^{th Molecular Spectroscopy Symposium}, Columbus, 2012

  19. Asymmetry in Platinum Acetylide Complexes: Confinement of the Triplet Exciton to the Lowest Energy Ligand (Preprint)

    DTIC Science & Technology

    2006-08-01

    lower energy thiophene units, but some emission is also observed from the higher energy phenyl units.4oThe study describes similar excited state...AFRL-ML-WP-TP-2007-530 ASYMMETRY IN PLATINUM ACETYLIDE COMPLEXES: CONFINEMENT OF THE TRIPLET EXCITON TO THE LOWEST ENERGY LIGAND (PREPRINT...GRANT NUMBER 4. TITLE AND SUBTITLE ASYMMETRY IN PLATINUM ACETYLIDE COMPLEXES: CONFINEMENT OF THE TRIPLET EXCITON TO THE LOWEST ENERGY LIGAND

  20. SU(3) gauge symmetry for collective rotational states in deformed nuclei

    NASA Astrophysics Data System (ADS)

    Rosensteel, George; Sparks, Nick

    2016-09-01

    How do deformed nuclei rotate? The qualitative answer is that a velocity-dependent interaction causes a strong coupling between the angular momentum and the vortex momentum (or Kelvin circulation). To achieve a quantitative explanation, we propose a significant extension of the Bohr-Mottelson legacy model in which collective wave functions are vector-valued in an irreducible representation of SU(3). This SU(3) is not the usual Elliott choice, but rather describes internal vorticity in the rotating frame. The circulation values C of an SU(3) irreducible representation, say the (8,0) for 20Ne, are C = 0, 2, 4, 6, 8, which is the same as the angular momentum spectrum in the Elliott model; the reason is a reciprocity theorem in the symplectic model. The differential geometry of Yang-Mills theory provides a natural mathematical framework to solve the angular-vortex coupling riddle. The requisite strong coupling is a ``magnetic-like'' interaction arising from the covariant derivative and the bundle connection. The model builds on prior work about the Yang-Mills SO(3) gauge group model.

  1. Engineering entanglement for metrology with rotating matter waves

    NASA Astrophysics Data System (ADS)

    Rico-Gutierrez, L. M.; Spiller, T. P.; Dunningham, J. A.

    2013-06-01

    Entangled states of rotating, trapped ultracold bosons form a very promising scenario for quantum metrology. In order to employ such states for metrology, it is vital to understand their detailed form and the enhanced accuracy with which they could measure phase, in this case generated through rotation. In this work, we study the rotation of ultracold bosons in an asymmetric trapping potential beyond the lowest Landau level (LLL) approximation. We demonstrate that while the LLL can identify reasonably the critical frequency for a quantum phase transition and entangled state generation, it is vital to go beyond the LLL to identify the details of the state and quantify the quantum Fisher information (which bounds the accuracy of the phase measurement). We thus identify a new parameter regime for useful entangled state generation, amenable to experimental investigation.

  2. An assessment of the determination of the tides and the rotation state of Ganymede with JUICE radio science experiment

    NASA Astrophysics Data System (ADS)

    Baland, Rose-Marie; Van Hoolst, Tim; Tobie, Gabriel; Dehant, Véronique

    2015-04-01

    Besides being the largest natural satellite known in the Solar System, Ganymede most likely also has the most differentiated internal structure of all satellites.Ganymede is thought to have an external water/ice layer subdivided into three sublayers: an outer ice shell, a global liquid water ocean, and a high pressure ice mantle. The presence of a water layer is supported by the possible detection of an induced magnetic field with the Galileo spacecraft. The metallic core is divided into a solid (inner core) and a liquid (outer core) part. Between the water/ice and the metallic layers, a rock mantle is expected. The JUpiter ICy moons Explorer (JUICE) mission led by ESA is planned to be launched in 2022. The spacecraft is expected to enter in orbit around Ganymede in september 2032. The Ganymede Tour will alternate elliptic and circular phases at different altitudes. The circular phases at altitudes of a few hundred kilometers are dedicated partly to the study of the internal structure such as the determination of the extent and composition of the ocean and of the surface ice shell. The payload of the spacecraft comprises the radio science package 3GM (Gravity and Geophysics of Jupiter and the Galilean Moons) that will be used to measure the Doppler effect on radio links between the orbiter and the Earth which will be affected by the gravity field of Ganymede. The gravity field of Ganymede is the sum of the static hydrostatic field (related to the secular Love number kf), of the periodically varying field due to tidal deformations (related to the tidal Love number k2 and the tidal dissipation factor Q), of the periodically varying field due to change in the rotation state (variations in the rotation rate and in the orientation of the rotation axis), and of the non-hydrostatic field that may be due to mass anomalies. The tidal and rotation parameters depend on the internal structure of the satellite (density, size, rheological properties of the different layers) in a

  3. Translational and rotational excitation of the CO{sub 2}(00{sup 0}0) vibrationless state in the collisional quenching of highly vibrationally excited 2-methylpyrazine: Kinetics and dynamics of large energy transfers

    SciTech Connect

    Sevy, Eric T.; Rubin, Seth M.; Lin, Zhen; Flynn, George W.

    2000-09-22

    The relaxation of highly vibrationally excited methylpyrazine (C{sub 5}N{sub 2}H{sub 6}) by collisions with CO{sub 2} molecules has been investigated over the temperature range 243-364 K using diode laser transient absorption spectroscopy. Particular focus is placed on understanding both the dynamical features and the kinetics of collisions which are accompanied by large energy transfers into the CO{sub 2} rotational and translational degrees of freedom. Vibrationally hot methylpyrazine (E{sup '}=40 987 cm{sup -1}) was prepared by 248 nm excimer laser pumping, followed by rapid radiationless transitions to the ground electronic state. The nascent rotational population distributions (J=58-80) of the 00{sup 0}0 ground state of CO{sub 2} resulting from collisions with hot methylpyrazine were probed at short times following the excimer laser pulse. Doppler spectroscopy was used to measure the distributions of CO{sub 2} recoil velocities for individual rotational levels of the 00{sup 0}0 state. In addition, the temperature dependence of the state resolved, absolute rate constants for collisions populating high J states of CO{sub 2} was determined. The rotational population distributions, distributions of recoil velocities, and quenching rates for production of CO{sub 2} high J states (J=58-80) exhibit a very weak temperature dependence. The slight temperature dependence indicates that CO{sub 2} molecules which scatter into high J states of the ground vibrationless level originate from rotational levels near the mean of the precollision thermal rotational distribution. A gap law model is used to estimate the average initial rotational state and velocity of the CO{sub 2} bath, which allows for the calculation of the energy transfer magnitudes, {delta}E. The measured energy transfer probabilities which are indexed by final bath state are resorted as a function of {delta}E to create the energy transfer distribution function, P(E,E{sup '}) from E{sup '}-E{approx}1500-6000 cm

  4. Preferential states of rotating turbulent flows in a square container with a step topography

    NASA Astrophysics Data System (ADS)

    Tenreiro, M.; Trieling, R. R.; Sansón, L. Zavala; van Heijst, G. J. F.

    2013-01-01

    The self-organization of confined, quasi-two-dimensional turbulent flows in a rotating square container with a step-like topography is investigated by means of laboratory experiments and numerical simulations based on a rigid lid, shallow-water formulation. The domain is divided by a bottom discontinuity into two rectangular regions, one being shallow and the other deep. The existence of a preferential vorticity distribution in the long-term evolution of the decaying flow is discussed. Initially, the turbulent flow organizes into larger structures. After a few rotation periods, a continuous jet-like flow is consistently observed along the step, with the shallow region at its right. This flow is associated with the adjustment of the fluid to equilibrium over a bottom discontinuity in an anti-clockwise rotating system. At the end of the step, two persistent structures are formed due to the collision of this jet with the vertical wall: a cyclonic circulation cell in the deep region, while an anticyclonic cell occurs in the shallow part of the domain. The laboratory experiments are well-reproduced by the simulations. Due to bottom friction effects, the fluid motion is halted before a complete organization of the flow is accomplished. In order to study the full process, additional numerical simulations were performed with zero Ekman friction. Same principal features are observed as in the experiments, but now a complete organization of the flow into four vortices is obtained: in the deep part of the flow domain, a cyclone-anticyclone pair is observed that fills up the entire region, and the mirrored double cell structure occurs on the shallow side. Such a disposition of the vortices is directly associated with the interaction of the flow along the step and the downstream wall at which it collides, as observed in the experiments. It is shown that this arrangement is systematically obtained in simulations with very different initial conditions. The existence of a

  5. Faraday Rotation Due to Surface States in the Topological Insulator (Bi1–xSbx)2Te3

    DOE PAGES

    Shao, Yinming; Post, Kirk W.; Wu, Jhih-Sheng; ...

    2016-12-29

    For this research, using magneto-infrared spectroscopy, we have explored the charge dynamics of (Bi,Sb)2Te3 thin films on InP substrates. From the magneto-transmission data we extracted three distinct cyclotron resonance (CR) energies that are all apparent in the broad band Faraday rotation (FR) spectra. This comprehensive FR-CR data set has allowed us to isolate the response of the bulk states from the intrinsic surface states associated with both the top and bottom surfaces of the film. Finally, the FR data uncovered that electron- and hole-type Dirac Fermions reside on opposite surfaces of our films, which paves the way for observing manymore » exotic quantum phenomena in topological insulators.« less

  6. Faraday Rotation Due to Surface States in the Topological Insulator (Bi1-xSbx)2Te3.

    PubMed

    Shao, Yinming; Post, Kirk W; Wu, Jhih-Sheng; Dai, Siyuan; Frenzel, Alex J; Richardella, Anthony R; Lee, Joon Sue; Samarth, Nitin; Fogler, Michael M; Balatsky, Alexander V; Kharzeev, Dmitri E; Basov, D N

    2017-02-08

    Using magneto-infrared spectroscopy, we have explored the charge dynamics of (Bi,Sb)2Te3 thin films on InP substrates. From the magneto-transmission data we extracted three distinct cyclotron resonance (CR) energies that are all apparent in the broad band Faraday rotation (FR) spectra. This comprehensive FR-CR data set has allowed us to isolate the response of the bulk states from the intrinsic surface states associated with both the top and bottom surfaces of the film. The FR data uncovered that electron- and hole-type Dirac Fermions reside on opposite surfaces of our films, which paves the way for observing many exotic quantum phenomena in topological insulators.

  7. Lowest enthalpy polymorph of cold-compressed graphite phase.

    PubMed

    Li, Da; Bao, Kuo; Tian, Fubo; Zeng, Zhenwu; He, Zhi; Liu, Bingbing; Cui, Tian

    2012-04-07

    Based on an ab initio evolutionary algorithm, a novel carbon polymorph with an orthorhombic Cmcm symmetry is predicted, named as C carbon, which has the lowest enthalpy among the previously proposed cold-compressed graphite phases.

  8. Fungicide rotation schemes for managing Phytophthora fruit rot of watermelon across southeastern United States

    USDA-ARS?s Scientific Manuscript database

    Southeastern states produce about 50% of the watermelons in the United States (U.S.) where conditions are optimal for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses to growers before and after harvest. ...

  9. Lowest Price Technically Acceptable: Why All the Debate?

    DTIC Science & Technology

    2015-04-01

    perceived overuse by the Department of Defense (DoD) of the Lowest Priced Technically Accept-able (LPTA) source-selection process. In appropriate...pressure on price . Furthermore, industry contends, overusing LPTA in the long haul will erode the DoD technological edge through low-cost/low-performance...contracting missions. Lowest Price Technically Acceptable Why All the Debate? Scott R. Calisti Report Documentation Page Form ApprovedOMB No. 0704-0188

  10. Piezoelectrically forced vibrations of electroded doubly rotated quartz plates by state space method

    NASA Technical Reports Server (NTRS)

    Chander, R.

    1990-01-01

    The purpose of this investigation is to develop an analytical method to study the vibration characteristics of piezoelectrically forced quartz plates. The procedure can be summarized as follows. The three dimensional governing equations of piezoelectricity, the constitutive equations and the strain-displacement relationships are used in deriving the final equations. For this purpose, a state vector consisting of stresses and displacements are chosen and the above equations are manipulated to obtain the projection of the derivative of the state vector with respect to the thickness coordinate on to the state vector itself. The solution to the state vector at any plane is then easily obtained in a closed form in terms of the state vector quantities at a reference plane. To simplify the analysis, simple thickness mode and plane strain approximations are used.

  11. Carbon stocks quantification in agricultural systems employing succession and rotation of crops in Rio Grande do Sul State, Brazil.

    NASA Astrophysics Data System (ADS)

    Walter, Michele K. C.; Marinho, Mara de A.; Denardin, José E.; Zullo, Jurandir, Jr.; Paz-González, Antonio

    2013-04-01

    Soil and vegetation constitute respectively the third and the fourth terrestrial reservoirs of Carbon (C) on Earth. C sequestration in these reservoirs includes the capture of the CO2 from the atmosphere by photosynthesis and its storage as organic C. Consequently, changes in land use and agricultural practices affect directly the emissions of the greenhouse gases and the C sequestration. Several studies have already demonstrated that conservation agriculture, and particularly zero tillage (ZT), has a positive effect on soil C sequestration. The Brazilian federal program ABC (Agriculture of Low Carbon Emission) was conceived to promote agricultural production with environmental protection and represents an instrument to achieve voluntary targets to mitigate emissions or NAMAS (National Appropriated Mitigation Actions). With financial resources of about US 1.0 billion until 2020 the ABC Program has a target of expand ZT in 8 million hectares of land, with reduction of 16 to 20 million of CO2eq. Our objective was to quantify the C stocks in soil, plants and litter of representative grain crops systems under ZT in Rio Grande do Sul State, Brazil. Two treatments of a long term experimental essay (> 20 years) were evaluated: 1) Crop succession with wheat (Triticum aestivum L.)/soybean (Glycine max (L.) Merril); 2) Crop rotation with wheat/soybean (1st year), vetch (Vicia sativa L.)/soybean (2nd year), and white oat (Avena sativa L.)/sorghum (Sorghum bicolor L.) (3rd year). C quantification in plants and in litter was performed using the direct method of biomass quantification. The soil type evaluated was a Humic Rhodic Hapludox, and C quantification was executed employing the method referred by "C mass by unit area". Results showed that soybean plants under crop succession presented greater C stock (4.31MgC ha-1) comparing with soybean plants cultivated under crop rotation (3.59 MgC ha-1). For wheat, however, greater C stock was quantified in plants under rotation

  12. Effect of molecular-orbital rotations on ground-state energies in the parametric two-electron reduced density matrix method.

    PubMed

    Sand, Andrew M; Mazziotti, David A

    2013-06-28

    Different sets of molecular orbitals and the rotations connecting them are of great significance in molecular electronic structure. Most electron correlation methods depend on a reference wave function that separates the orbitals into occupied and unoccupied spaces. Energies and properties from these methods depend upon rotations between the spaces. Some electronic structure methods, such as modified coupled electron pair approximations and the recently developed parametric two-electron reduced density matrix (2-RDM) methods [D. A. Mazziotti, Phys. Rev. Lett. 101, 253002 (2008)], also depend upon rotations between occupied orbitals and rotations between unoccupied orbitals. In this paper, we explore the sensitivity of the ground-state energies from the parametric 2-RDM method to rotations within the occupied space and within the unoccupied space. We discuss the theoretical origin of the rotational dependence and provide computational examples at both equilibrium and non-equilibrium geometries. We also study the effect of these rotations on the size extensivity of the parametric 2-RDM method. Computations show that the orbital rotations have a small effect upon the parametric 2-RDM energies in comparison to the energy differences observed between methodologies such as coupled cluster and parametric 2-RDM. Furthermore, while the 2-RDM method is rigorously size extensive in a local molecular orbital basis set, calculations reveal negligible deviations in nonlocal molecular orbital basis sets such as those from canonical Hartree-Fock calculations.

  13. Millimeter Wave Spectra of the Internal Rotation Excited States of (o)H_2-H_2O and (o)H_2-D_2O

    NASA Astrophysics Data System (ADS)

    Harada, K.; Iwasaki, Y.; Giesen, T.; Tanaka, K.

    2013-06-01

    H_2-H_2O is a weakly bound complex and it has a various states according to the internal rotation for both H_2 and H_2O moieties. In our previous study, we have reported the pure rotational transitions of the (o)H_2 complex in the ground H_2O rotational state, 0_{00}(Σ), for both H_2-H_2O and H_2-D_2O, where (o)H_2 (j_{ H2} =1) is rotating perpendicular to the intermolecular axis to give the projection of j_{ H2} to the axis k_{ H2} to be zero (i.e. Σ state). In the present study, we have observed the rotational transitions for the 0_{00} (Π) states in the millimeter-wave region up to 220 GHz, where the (o)H_2 is rotating around the intermolecular axis to give the projection k_{ H2} to be one (i.e. Π state). The center of mass bond lengths derived from the observed rotational constants for 0_{00} (Π) are longer by 5 % than those for 0_{00} (Σ), while force constants for the intermolecular stretching for 0_{00} (Π) derived from centrifugal distortion constants are smaller by 23 % than those for 0_{00} (Σ), suggesting the Π and Σ substates have quite different structures. The recent theoretical calculation indicates that for 0_{00}(Σ), (o)H_2 is bound to the oxygen site of H_2O, while for the 0_{00} (Π) state, (o)H_2 to the hydrogen site of H_2O, and the 0_{00}(Σ) state is by 14 cm^{-1} more stable than the 0_{00} (Π) state. Observed molecular constants for 0_{00}(Σ) and (Π) are consistent with the structures given by the theoretical calculation. We also observed the rotational spectrum in the 1_{01} (Σ) and (Π) states, where Σ and Π correspond to the rotation of H_2O perpendicular and parallel to the intermolecular axis and (o)H_2 is calculated to be bound to the oxygen site of H_2O. The energy difference between the 1_{01} (Σ) and (Π) states will be discussed due to the Criolis interaction between these substates. C. J. Whitham, K. Tanaka, and K. Harada, The 56th OSU Symposium, RD08 (2001). Ad. van der Avoid and D. J. Nesbit, J. Chem. Phys

  14. Rotationally resolved state-to-state photoionization and photoelectron study of titanium carbide and its cation (TiC/TiC+)

    NASA Astrophysics Data System (ADS)

    Luo, Zhihong; Huang, Huang; Chang, Yih-Chung; Zhang, Zheng; Yin, Qing-Zhu; Ng, C. Y.

    2014-10-01

    Titanium carbide and its cation (TiC/TiC+) have been investigated by the two-color visible (VIS)-ultraviolet (UV) resonance-enhanced photoionization and pulsed field ionization-photoelectron (PFI-PE) methods. Two visible excitation bands for neutral TiC are observed at 16 446 and 16 930 cm-1. Based on rotational analyses, these bands are assigned as the respective TiC(3Π1) ← TiC(X3Σ+) and TiC(3Σ+) ← TiC(X3Σ+) transition bands. This assignment supports that the electronic configuration and term symmetry for the neutral TiC ground state are …7σ28σ19σ13π4 (X3Σ+). The rotational constant and the corresponding bond distance of TiC(X3Σ+; v″ = 0) are determined to be B0″ = 0.6112(10) cm-1 and r0″ = 1.695(2) Å, respectively. The rotational analyses of the VIS-UV-PFI-PE spectra for the TiC+(X; v+ = 0 and 1) vibrational bands show that the electronic configuration and term symmetry for the ionic TiC+ ground state are …7σ28σ13π4 (X2Σ+) with the v+ = 0 → 1 vibrational spacing of 870.0(8) cm-1 and the rotational constants of Be+ = 0.6322(28) cm-1, and αe+ = 0.0085(28) cm-1. The latter rotational constants yield the equilibrium bond distance of re+ = 1.667(4) Å for TiC+(X2Σ+). The cleanly rotationally resolved VIS-UV-PFI-PE spectra have also provided a highly precise value of 53 200.2(8) cm-1 [6.5960(1) eV] for the adiabatic ionization energy (IE) of TiC. This IE(TiC) value along with the known IE(Ti) has made possible the determination of the difference between the 0 K bond dissociation energy (D0) of TiC+(X2Σ+) and that of TiC(X3Σ+) to be D0(Ti+-C) - D0(Ti-C) = 0.2322(2) eV. Similar to previous experimental observations, the present state-to-state PFI-PE study of the photoionization transitions, TiC+(X2Σ+; v+ = 0 and 1, N+) ← TiC(3Π1; v', J'), reveals a strong decreasing trend for the photoionization cross section as |ΔN+| = |N+ - J'| is increased. The maximum |ΔN+| change of 7 observed here is also consistent with the previous

  15. Rotationally resolved state-to-state photoionization and photoelectron study of titanium carbide and its cation (TiC/TiC⁺).

    PubMed

    Luo, Zhihong; Huang, Huang; Chang, Yih-Chung; Zhang, Zheng; Yin, Qing-Zhu; Ng, C Y

    2014-10-14

    Titanium carbide and its cation (TiC/TiC(+)) have been investigated by the two-color visible (VIS)-ultraviolet (UV) resonance-enhanced photoionization and pulsed field ionization-photoelectron (PFI-PE) methods. Two visible excitation bands for neutral TiC are observed at 16,446 and 16,930 cm(-1). Based on rotational analyses, these bands are assigned as the respective TiC((3)Π1) ← TiC(X(3)Σ(+)) and TiC((3)Σ(+)) ← TiC(X(3)Σ(+)) transition bands. This assignment supports that the electronic configuration and term symmetry for the neutral TiC ground state are …7σ(2)8σ(1)9σ(1)3π(4) (X(3)Σ(+)). The rotational constant and the corresponding bond distance of TiC(X(3)Σ(+); v″ = 0) are determined to be B0″ = 0.6112(10) cm(-1) and r0″ = 1.695(2) Å, respectively. The rotational analyses of the VIS-UV-PFI-PE spectra for the TiC(+)(X; v(+) = 0 and 1) vibrational bands show that the electronic configuration and term symmetry for the ionic TiC(+) ground state are …7σ(2)8σ(1)3π(4) (X(2)Σ(+)) with the v(+) = 0 → 1 vibrational spacing of 870.0(8) cm(-1) and the rotational constants of B(e)(+) = 0.6322(28) cm(-1), and α(e)(+) = 0.0085(28) cm(-1). The latter rotational constants yield the equilibrium bond distance of r(e)(+) = 1.667(4) Å for TiC(+)(X(2)Σ(+)). The cleanly rotationally resolved VIS-UV-PFI-PE spectra have also provided a highly precise value of 53 200.2(8) cm(-1) [6.5960(1) eV] for the adiabatic ionization energy (IE) of TiC. This IE(TiC) value along with the known IE(Ti) has made possible the determination of the difference between the 0 K bond dissociation energy (D0) of TiC(+)(X(2)Σ(+)) and that of TiC(X(3)Σ(+)) to be D0(Ti(+)-C) - D0(Ti-C) = 0.2322(2) eV. Similar to previous experimental observations, the present state-to-state PFI-PE study of the photoionization transitions, TiC(+)(X(2)Σ(+); v(+) = 0 and 1, N(+)) ← TiC((3)Π1; v', J'), reveals a strong decreasing trend for the photoionization cross section as |ΔN(+)| = |N

  16. Radiative Rotational Lifetimes and State-Resolved Relative Detachment Cross Sections from Photodetachment Thermometry of Molecular Anions in a Cryogenic Storage Ring

    NASA Astrophysics Data System (ADS)

    Meyer, C.; Becker, A.; Blaum, K.; Breitenfeldt, C.; George, S.; Göck, J.; Grieser, M.; Grussie, F.; Guerin, E. A.; von Hahn, R.; Herwig, P.; Krantz, C.; Kreckel, H.; Lion, J.; Lohmann, S.; Mishra, P. M.; Novotný, O.; O'Connor, A. P.; Repnow, R.; Saurabh, S.; Schwalm, D.; Schweikhard, L.; Spruck, K.; Sunil Kumar, S.; Vogel, S.; Wolf, A.

    2017-07-01

    Photodetachment thermometry on a beam of OH- in a cryogenic storage ring cooled to below 10 K is carried out using two-dimensional frequency- and time-dependent photodetachment spectroscopy over 20 min of ion storage. In equilibrium with the low-level blackbody field, we find an effective radiative temperature near 15 K with about 90% of all ions in the rotational ground state. We measure the J =1 natural lifetime (about 193 s) and determine the OH- rotational transition dipole moment with 1.5% uncertainty. We also measure rotationally dependent relative near-threshold photodetachment cross sections for photodetachment thermometry.

  17. Rotational and vibrational dynamics in the excited electronic state of deprotonated and protonated fluorescein studied by time-resolved photofragmentation in an ion trap.

    PubMed

    Imanbaew, Dimitri; Gelin, Maxim F; Riehn, Christoph

    2016-07-01

    Excited state dynamics of deprotonated and protonated fluorescein were investigated by polarization dependent femtosecond time-resolved pump-probe photofragmentation in a 3D ion trap. Transients of deprotonated fluorescein exhibit vibrational wavepacket dynamics with weak polarization dependence. Transients of protonated fluorescein show only effects of molecular alignment and rotational dephasing. The time resolved rotational anisotropy of protonated fluorescein is simulated by the calculated orientational correlation function. The observed differences between deprotonated and protonated fluorescein are ascribed to their different higher lying electronically excited states and corresponding structures. This is partially supported by time-dependent density functional theory calculations of the excited state structures.

  18. Rotational and vibrational dynamics in the excited electronic state of deprotonated and protonated fluorescein studied by time-resolved photofragmentation in an ion trap

    PubMed Central

    Imanbaew, Dimitri; Gelin, Maxim F.; Riehn, Christoph

    2016-01-01

    Excited state dynamics of deprotonated and protonated fluorescein were investigated by polarization dependent femtosecond time-resolved pump-probe photofragmentation in a 3D ion trap. Transients of deprotonated fluorescein exhibit vibrational wavepacket dynamics with weak polarization dependence. Transients of protonated fluorescein show only effects of molecular alignment and rotational dephasing. The time resolved rotational anisotropy of protonated fluorescein is simulated by the calculated orientational correlation function. The observed differences between deprotonated and protonated fluorescein are ascribed to their different higher lying electronically excited states and corresponding structures. This is partially supported by time-dependent density functional theory calculations of the excited state structures. PMID:27376104

  19. Torsional Splitting in the Rotational Spectrum from 8 TO 650 GHz of the Ground State of 1,1-DIFLUOROACETONE

    NASA Astrophysics Data System (ADS)

    Margules, L.; Motiyenko, R. A.; Groner, P.; De Chirico, F.; Turk, A.; Cooke, S. A.

    2013-06-01

    Measurements on the rotational spectrum of 1,1-difluoroacetone have been extended from the cm-wave region into the mm-wave region. Measurements between 150 GHz and 600 GHz were performed a t Lille at room temperature. About 2000 transitions have been added to the known line listing for the ground state. The range of J and K_{-1} values, for both the A and E torsional substates, now span 1 - 60 and 0 - 30, respectively. Analysis of the cm-wave spectrum was only possible using the Watson S-reduced Hamiltonian, with the A-reduction producing a poor spectral fit. For that analysis only quartic centrifugal distortion terms were required. With the newly recorded higher J and K_{-1} measurements it is necessary to expand the Hamiltonian to now include sextic and octic centrifugal distortion terms. This should allow us to extend the assignment to even higher J and K_{-1} and perhaps to shed more light into failure of the A-reduction Hamiltonian to achieve a satisfactory fit for the cm-wave transitions. The effective barrier to methyl group internal rotation has been determined more accurately. G. S. Grubbs II, P. Groner, S. E. Novick and S. A. Cooke J. Mol. Spectrosc. {280} 21-26, 2012.

  20. Efficient spectral computation of the stationary states of rotating Bose-Einstein condensates by preconditioned nonlinear conjugate gradient methods

    NASA Astrophysics Data System (ADS)

    Antoine, Xavier; Levitt, Antoine; Tang, Qinglin

    2017-08-01

    We propose a preconditioned nonlinear conjugate gradient method coupled with a spectral spatial discretization scheme for computing the ground states (GS) of rotating Bose-Einstein condensates (BEC), modeled by the Gross-Pitaevskii Equation (GPE). We first start by reviewing the classical gradient flow (also known as imaginary time (IMT)) method which considers the problem from the PDE standpoint, leading to numerically solve a dissipative equation. Based on this IMT equation, we analyze the forward Euler (FE), Crank-Nicolson (CN) and the classical backward Euler (BE) schemes for linear problems and recognize classical power iterations, allowing us to derive convergence rates. By considering the alternative point of view of minimization problems, we propose the preconditioned steepest descent (PSD) and conjugate gradient (PCG) methods for the GS computation of the GPE. We investigate the choice of the preconditioner, which plays a key role in the acceleration of the convergence process. The performance of the new algorithms is tested in 1D, 2D and 3D. We conclude that the PCG method outperforms all the previous methods, most particularly for 2D and 3D fast rotating BECs, while being simple to implement.

  1. State-resolved rotational energy transfer in open shell collisions: Cl(2P3/2)+HCl

    NASA Astrophysics Data System (ADS)

    Zhao, Zhong-Quan; Chapman, William B.; Nesbitt, David J.

    1995-05-01

    Time- and frequency-resolved infrared (IR) laser absorption methods are used to probe hot atom energy transfer in open shell interactions of Cl(2P3/2)+HCl(J) in the single collision regime. The Cl(2P3/2) atoms are prepared by 308 nm laser photolysis of Cl2, and suffer collisions at Erel¯˜3500 cm-1 with a room temperature HCl distribution in a fast flow cell. Selective collisional excitation of final HCl(Jf) states is monitored by transient IR absorption on R(J≥4) branch lines in the HCl(v=1←0) band, while depletion of the initial HCl(Ji) states is monitored by transient bleaching of the room temperature Doppler profiles. Analysis of the J dependent Doppler profiles permits extraction of rotational loss [σloss(Ji)=∑fP(Ji)ṡσf←i] and gain [σgain(Jf)=∑iP(Ji)ṡσf←i] cross sections, as a function of initial and final J states, respectively. Absolute transient concentrations of the HCl(Ji) and HCl(Jf) are measured directly from absorbances via Beer's Law, and used to extract absolute collisional cross sections. The results are compared with quasiclassical trajectory (QCT) calculations on a hybrid ab initio/LEPS surface of Schatz and Gordon, which prove remarkably successful in reproducing both the J dependent trends and absolute values of the state-resolved gain and loss collision cross sections.

  2. Nascent rotational distribution for LiH(v = 0-3,J) states from collisions with H2(E = 4300 and 4800cm-1)

    NASA Astrophysics Data System (ADS)

    Shen, Xiaoyan; Wang, Shuying; Dai, Kang; Shen, Yifan

    2017-02-01

    Rotationally state selective excitation of H2(v = 1, J = 1 or 3) was achieved by stimulated Raman pumping. The full state-resolved distribution of scattered LiH(v = 0-3, J = 0 13)molecules from collisions with excited H2(E = 4300 and 4800 cm- 1) is reported. Nascent rotational and translational energy profiles for scattered LiH(v = 0 3) molecules with J = 0 13 were measured using high-resolution transient laser induced fluorescence(LIF). The product translational energy for individual J-states increases by 120% for a 13% increase in donor energy. The scattered LiH(v = 0, J = 0 13) molecules have a biexponential rotational distribution. Fitting the data with a two-component exponential model yields a low-energy distribution and a high-energy distribution. The rotational distribution is sensitive to donor energy. Rotational distributions of scatted LiH(v = 1-3) molecules were also measured. The distribution yielded rotational temperatures at 690 K for LiH/H2(E = 4300 cm- 1) and 730 K for LiH/H2(E = 4800 cm- 1), respectively. The rate constants for appearance LiH(v = 0-3,J) were determined.

  3. Predicting yields of short-rotation hybrid poplar (Populus spp.) for the United States through model-data synthesis.

    PubMed

    Wang, Dan; LeBauer, David; Dietze, Michael

    2013-06-01

    Hybrid poplar (Populus spp.) is an important biomass crop being evaluated for cellulosic ethanol production. Predictions of poplar growth, rotation period, and soil carbon sequestration under various growing conditions, soils, and climates are critical for farmers and managers planning to establish short-rotation forestry (SRF) plantations. In this study, we used an ecoinformatics workflow, the Predictive Ecosystem Analyzer (PEcAn), to integrate literature data and field measurements into the Ecosystem Demography 2 (ED2) model to estimate yield potential of poplar plantations. Within PEcAn 164 records of seven different traits from the literature were assimilated using a Bayesian meta-analysis. Next, variance decomposition identified seven variables for further constraint that contributed > 80% to the uncertainty in modeled yields: growth respiration, dark respiration, quantum efficiency, mortality coefficient, water conductance, fine-root allocation, and root turnover rate. Assimilation of observed yields further constrained uncertainty in model parameters (especially dark respiration and root turnover rate) and biomass estimates. Additional measurements of growth respiration, mortality, water conductance, and quantum efficiency would provide the most efficient path toward further constraint of modeled yields. Modeled validation demonstrated that ED2 successfully captured the interannual and spatial variability of poplar yield observed at nine independent sites. Site-level analyses were conducted to estimate the effect of land use change to SRF poplar on soil C sequestration compared to alternate land uses. These suggest that poplar plantations became a C sink within 18 years of conversion from corn production or existing forest. Finally, poplar yields were estimated for the contiguous United States at a half degree resolution in order to determine potential productivity, estimate the optimal rotation period, and compare poplar to perennial grass yields. This

  4. Rotational state of the nucleus of Comet 9P/Tempel 1: Results from Hubble Space Telescope observations in 2004

    NASA Astrophysics Data System (ADS)

    Lamy, Philippe L.; Toth, Imre; A'Hearn, Michael F.; Weaver, Harold A.; Jorda, Laurent

    The nucleus of Comet 9P/Tempel 1 was first observed with the Hubble Space Telescope (HST) in December 1997 [Lamy, P., Toth, I., A'Hearn, M.F., Weaver, H., Weissman, P.R., 2001. Icarus 154, 337 344], but the temporal coverage was insufficient to determine its rotational period. Because the success of the Deep Impact mission was critically dependent on understanding the rotational state and approximate shape and size of the nucleus, we extensively re-observed 9P/Tempel 1, this time with the Advanced Camera for Surveys (HST/ACS), from May 7.9 to 9.5, 2004 (UT). At the mid-point of the observing window, the comet was 3.52 AU from the Sun, 4.03 AU from the Earth, and at a solar phase angle of 13.3°. The program was comprised of 18 separate visits, each one corresponding to an HST orbit filled with 3 ACS exposures of either 800 or 857 s duration with the F606W broadband filter. These very deep exposures revealed a star-like object, without any apparent coma. The light curve, defined by 49 data points, is characterized by a mean apparent V magnitude of 21.8 and an amplitude of 0.5 mag, indicating that we were viewing the varying cross-section of a rotating, elongated body. The periodicity was analyzed with seven different techniques yielding a rotational period in the range 39.40 to 43.00 h, and a mean value of 41.27±1.85 h (1σ). Using an albedo p=0.04 and a linear phase law with a coefficient β=0.0465 magdeg, we determined an effective radius of 3.01 km; a possible prolate spheroid solution has semi-axes a=3.71 km, b=2.36 km and a minimum axial ratio a/b˜1.57. By comparing the light curves obtained in 1997 and in 2004, we were able to constrain the phase function of the nucleus. Finally, an upper limit of Afρ<0.04 cm is set based on the non-detection of the coma.

  5. An Analysis of the Rotational Spectrum of Acetonitrile (CH_3CN) in Excited Vibrational States

    NASA Astrophysics Data System (ADS)

    Neese, Christopher F.; McMillan, James; Fortman, Sarah; De Lucia, Frank C.

    2014-06-01

    Acetonitrile (CH_3CN) is a well-known interstellar molecule whose vibrationally excited states need to be accounted for in searches for new molecules in the interstellar medium. To help catalog such `weed' molecules, we have developed a technique that involves recording complete spectra over a range of astrophysically significant temperatures. With such a data set, we can experimentally measure the line strengths and lower state energies of unassigned lines in the spectrum. In this talk we will present the ongoing analysis of complete temperature resolved spectra in the 215-265 GHz and 570-650 GHz regions. We have been able to assign many vibrationally hot lines from this data and a room temperature data set spanning 165-700 GHz. To date, we have assigned lines from most of the vibrational states below ν_6 at 1448 wn.

  6. Rotationally resolved (3 + 1) rempi of H 2 via the B 1Σ +u state

    NASA Astrophysics Data System (ADS)

    Lynch, D. L.; Dixit, S. N.; McKoy, V.

    1986-01-01

    In the paper, we compare the results of our ab initio calculations for the ro-vibrational branching ratios resulting from a (3+1) REMPI of H 2 via the B 1Σ +u state with the experimental data of Pratt, Poliakoff, Dehmer and Dehmer. These results indicate that non-Franck-Condon effects are less important here than in the (3+1) REMPI of H 2 via the C 1Π u state. We observe that the Δ J = ±3 peaks in the photoelectron spectrum are of negligible strength and that the ratio of Δ J = +1 to Δ J = -1 peak is independent of the ionic vibrational state. A detailed analysis indicates that these features arise as a result of a dynamic interference between the do and dμ ionization channels and do not imply either the smallness of the d-wave or the smallness of the j t = 3 angular momentum coupling terms.

  7. The emergence of deformation and rotational states in the many-nucleon quantum theory of nuclei

    NASA Astrophysics Data System (ADS)

    Rowe, D. J.

    2016-02-01

    The many-nucleon quantum mechanics of a nucleus is infinite-dimensional and, although simply defined, it has the potential for unlimited complexity. Nevertheless, the low-energy states of heavy open-shell nuclei exhibit properties that are remarkably well described by simple collective models. This paper examines this emergent simplicity from a perspective that closely parallels the emergence of shell structure in the Mayer-Jensen model. The result is an expression of the many-nucleon Hilbert space of a nucleus as an energy-ordered sum of subspaces each of which carries a microscopic version of the Bohr-Mottelson unified model. Each of the subspaces is characterized by nuclear states with a common intrinsic shape defined by its quadrupole moments. An emergence of simplicity and shape-coexistence in nuclei is then explained if it can be demonstrated that there is a relatively small and coherent mixing of the states of different collective subspaces.

  8. Determination of the rotational population of H2 and D2 including high-N states in low temperature plasmas via the Fulcher-α transition

    NASA Astrophysics Data System (ADS)

    Briefi, S.; Rauner, D.; Fantz, U.

    2017-01-01

    Vibrational and rotational excitation of the hydrogen molecule can significantly affect molecular reaction rates in low pressure low temperature plasmas, for example for the creation of H- /D- ions via the dissociative attachment process. In general, the rotational population in these discharges is known to be non-thermal with an overpopulation of states with high rotational quantum number N. In contrast to a sophisticated direct measurement of the rotational distribution in the X g+1 Σ, v = 0 state, it is demonstrated that the determination can also be carried out up to high-N levels rather easily via optical emission spectroscopy utilizing the Fulcher-α transition of H2 and D2. The measured rotational populations can be described with a two-temperature distribution where the cold part reflects the population according to the gas temperature of the discharge. This has been verified by using the emission of the second positive system of nitrogen as independent gas temperature diagnostic. The hot part where the rotational temperature reaches several thousand Kelvin arises most probably from recombinative desorption of hydrogen at the discharge vessel wall where parts of the binding energy are converted into rotational excitation. Neglecting the hot population - what is often done when using the Fulcher-α transition as gas temperature diagnostic - can lead to a strong overestimation of Tgas. No fundamental differences in the rotational distributions between hydrogen and deuterium have been found, only the hot rotational temperature is smaller for D2 indicating an isotope-dependency of the recombinative desorption process.

  9. Surface-catalyzed recombination into excited electronic, vibrational, rotational, and kinetic energy states: A review

    NASA Technical Reports Server (NTRS)

    Kofsky, I. L.; Barrett, J. L.

    1985-01-01

    Laboratory experiments in which recombined CO, CO2, D2O, OH, N2, H2, and O2 molecules desorb from surfaces in excited internal and translational states are briefly reviewed. Unequilibrated distributions predominate from the principally catalytic metal substrates so far investigated. Mean kinetic energies have been observed up to approx. 3x, and in some cases less than, wall-thermal; the velocity distributions generally vary with emission angle, with non-Lambertian particle fluxes. The excitation state populations are found to depend on surface impurities, in an as yet unexplained way.

  10. Theoretical study of Raman chirped adiabatic passage by X-ray absorption spectroscopy: Highly excited electronic states and rotational effects

    SciTech Connect

    Engin, Selma; Sisourat, Nicolas Selles, Patricia; Taïeb, Richard; Carniato, Stéphane

    2014-06-21

    Raman Chirped Adiabatic Passage (RCAP) is an efficient method to climb the vibrational ladder of molecules. It was shown on the example of fixed-in-space HCl molecule that selective vibrational excitation can thus be achieved by RCAP and that population transfer can be followed by X-ray Photoelectron spectroscopy [S. Engin, N. Sisourat, P. Selles, R. Taïeb, and S. Carniato, Chem. Phys. Lett. 535, 192–195 (2012)]. Here, in a more detailed analysis of the process, we investigate the effects of highly excited electronic states and of molecular rotation on the efficiency of RCAP. Furthermore, we propose an alternative spectroscopic way to monitor the transfer by means of X-ray absorption spectra.

  11. Bound and resonance states of the dipolar anion of hydrogen cyanide: Competition between threshold effects and rotation in an open quantum system

    DOE PAGES

    Fossez, K.; Michel, N.; Nazarewicz, W.; ...

    2015-01-12

    In this paper, bound and resonance states of the dipole-bound anion of hydrogen cyanide HCN– are studied using a nonadiabatic pseudopotential method and the Berggren expansion technique involving bound states, decaying resonant states, and nonresonant scattering continuum. We devise an algorithm to identify the resonant states in the complex energy plane. To characterize spatial distributions of electronic wave functions, we introduce the body-fixed density and use it to assign families of resonant states into collective rotational bands. We find that the nonadiabatic coupling of electronic motion to molecular rotation results in a transition from the strong-coupling to weak-coupling regime. Inmore » the strong-coupling limit, the electron moving in a subthreshold, spatially extended halo state follows the rotational motion of the molecule. Above the ionization threshold, the electron's motion in a resonance state becomes largely decoupled from molecular rotation. Finally, the widths of resonance-band members depend primarily on the electron orbital angular momentum.« less

  12. Bound and resonance states of the dipolar anion of hydrogen cyanide: Competition between threshold effects and rotation in an open quantum system

    SciTech Connect

    Fossez, K.; Michel, N.; Nazarewicz, W.; Płoszajczak, M.; Jaganathen, Y.

    2015-01-12

    In this paper, bound and resonance states of the dipole-bound anion of hydrogen cyanide HCN are studied using a nonadiabatic pseudopotential method and the Berggren expansion technique involving bound states, decaying resonant states, and nonresonant scattering continuum. We devise an algorithm to identify the resonant states in the complex energy plane. To characterize spatial distributions of electronic wave functions, we introduce the body-fixed density and use it to assign families of resonant states into collective rotational bands. We find that the nonadiabatic coupling of electronic motion to molecular rotation results in a transition from the strong-coupling to weak-coupling regime. In the strong-coupling limit, the electron moving in a subthreshold, spatially extended halo state follows the rotational motion of the molecule. Above the ionization threshold, the electron's motion in a resonance state becomes largely decoupled from molecular rotation. Finally, the widths of resonance-band members depend primarily on the electron orbital angular momentum.

  13. Torsion - Rotation - Vibration Effects in the Ground and First Excited States of Methacrolein and Methyl Vinyl Ketone

    NASA Astrophysics Data System (ADS)

    Zakharenko, Olena; Motiyenko, R. A.; Aviles Moreno, Juan-Ramon; Huet, T. R.

    2016-06-01

    Methacrolein and methyl vinyl ketone are the two major oxidation products of isoprene emitted in the troposphere. New spectroscopic information is provided with the aim to allow unambiguous identification of these molecules, characterized by a large amplitude motion associated with the methyl top. State-of-the-art millimeter-wave spectroscopy experiments coupled to quantum chemical calculations have been performed. Comprehensive sets of molecular parameters have been obtained. The torsion-rotation-vibration effects will be discussed in detail. From the atmospheric application point of view the results provide precise ground state molecular constants essential as a foundation (by using the Ground State Combination Differences method) for the analysis of high resolution spectrum, recorded from 600 to 1600 wn. The infrared range can be then refitted using appropriate Hamiltonian parameters. The present work is funded by the French ANR through the PIA under contract ANR-11-LABX-0005-01 (Labex CaPPA), by the Regional Council Nord-Pas de Calais and by the European Funds for Regional Economic Development (FEDER).

  14. Binding of Phytopolyphenol Piceatannol Disrupts β/γ Subunit Interactions and Rate-limiting Step of Steady-state Rotational Catalysis in Escherichia coli F1-ATPase*

    PubMed Central

    Sekiya, Mizuki; Nakamoto, Robert K.; Nakanishi-Matsui, Mayumi; Futai, Masamitsu

    2012-01-01

    In observations of single molecule behavior under Vmax conditions with minimal load, the F1 sector of the ATP synthase (F-ATPase) rotates through continuous cycles of catalytic dwells (∼0.2 ms) and 120° rotation steps (∼0.6 ms). We previously established that the rate-limiting transition step occurs during the catalytic dwell at the initiation of the 120° rotation. Here, we use the phytopolyphenol, piceatannol, which binds to a pocket formed by contributions from α and β stator subunits and the carboxyl-terminal region of the rotor γ subunit. Piceatannol did not interfere with the movement through the 120° rotation step, but caused increased duration of the catalytic dwell. The duration time of the intrinsic inhibited state of F1 also became significantly longer with piceatannol. All of the beads rotated at a lower rate in the presence of saturating piceatannol, indicating that the inhibitor stays bound throughout the rotational catalytic cycle. The Arrhenius plot of the temperature dependence of the reciprocal of the duration of the catalytic dwell (catalytic rate) indicated significantly increased activation energy of the rate-limiting step to trigger the 120° rotation. The activation energy was further increased by combination of piceatannol and substitution of γ subunit Met23 with Lys, indicating that the inhibitor and the β/γ interface mutation affect the same transition step, even though they perturb physically separated rotor-stator interactions. PMID:22582396

  15. Effect of rotational-state-dependent molecular alignment on the optical dipole force

    NASA Astrophysics Data System (ADS)

    Kim, Lee Yeong; Lee, Ju Hyeon; Kim, Hye Ah; Kwak, Sang Kyu; Friedrich, Bretislav; Zhao, Bum Suk

    2016-07-01

    The properties of molecule-optical elements such as lenses or prisms based on the interaction of molecules with optical fields depend in a crucial way on the molecular quantum state and its alignment created by the optical field. Herein, we consider the effects of state-dependent alignment in estimating the optical dipole force acting on the molecules and, to this end, introduce an effective polarizability which takes proper account of molecular alignment and is directly related to the alignment-dependent optical dipole force. We illustrate the significance of including molecular alignment in the optical dipole force by a trajectory study that compares previously used approximations with the present approach. The trajectory simulations were carried out for an ensemble of linear molecules subject to either propagating or standing-wave optical fields for a range of temperatures and laser intensities. The results demonstrate that the alignment-dependent effective polarizability can serve to provide correct estimates of the optical dipole force, on which a state-selection method applicable to nonpolar molecules could be based. We note that an analogous analysis of the forces acting on polar molecules subject to an inhomogeneous static electric field reveals a similarly strong dependence on molecular orientation.

  16. Structure determination of membrane proteins in their native phospholipid bilayer environment by rotationally aligned solid-state NMR spectroscopy.

    PubMed

    Opella, Stanley J

    2013-09-17

    One of the most important topics in experimental structural biology is determining the structures of membrane proteins. These structures represent one-third of all of the information expressed from a genome, distinguished by their locations within the phospholipid bilayer of cells, organelles, or enveloped viruses. Their highly hydrophobic nature and insolubility in aqueous media means that they require an amphipathic environment. They have unique functions in transport, catalysis, channel formation, and signaling. Researchers are particularly interested in G-protein coupled receptors (GPCRs) because they modulate many biological processes, and about half of the approximately 800 of these proteins within the human genome are or can be turned into drug receptors that affect a wide range of diseases. Because of experimental difficulties, researchers have studied membrane proteins using a wide variety of artificial media that mimic membranes, such as mixed organic solvents or detergents. More sophisticated mimics include bilayer discs (bicelles) and the lipid cubic phase (LCP), but both of these contain a very large detergent component, which can disrupt the stability and function of membrane proteins. To have confidence in the resulting structures and their biological functions and to avoid disrupting these delicate proteins, the structures of membrane proteins should be determined in their native environment of liquid crystalline phospholipid bilayers under physiological conditions. This Account describes a recently developed general method for determining the structures of unmodified membrane proteins in phospholipid bilayers by solid-state NMR spectroscopy. Because it relies on the natural, rapid rotational diffusion of these proteins about the bilayer normal, this method is referred to as rotationally aligned (RA) solid-state NMR. This technique elaborates on oriented sample (OS) solid-state NMR, its complementary predecessor. These methods exploit the power of

  17. Progress in the Rotational Analysis of the Ground and Low-Lying Vibrationally Excited States of Malonaldehyde

    NASA Astrophysics Data System (ADS)

    Goudreau, E. S.; Tokaryk, Dennis W.; Ross, Stephen Cary; Billinghurst, Brant E.

    2016-06-01

    Despite being an important prototype molecule for intramolecular proton tunnelling, the far-IR spectrum of the internally hydrogen-bonded species malonaldehyde (C_3O_2H_4) is not yet well understood. In the talk I gave at the ISMS meeting in 2015 I discussed the high-resolution spectra we obtained at the Canadian Light Source synchrotron in Saskatoon, Saskatchewan. These spectra include a number of fundamental vibrational bands in the 100-2000 cm-1 region. In our efforts to analyze these bands we have noticed that our ground state combination differences show a large drift (up to an order of magnitude larger than our experimental error) away from those calculated using constants established by Baba et al., particularly in regions of high J (above 30) and low Ka (below 5). An examination of the previous microwave and far-IR studies reveals that this region of J-Ka space was not represented in the lines that Baba et al. used to generate the values for their fitting parameters. By including our own measurements in the fitting, we were able to improve the characterization of the ground state so that it is now consistent with all of the existing data. This characterization now covers a much larger range of J-Ka space and has enabled us to make significant progress in analyzing our far-IR synchrotron spectra. These include an excited vibrational state at 241 cm-1 as well as several states split by the tunnelling effect at higher wavenumber. T. Baba, T. Tanaka, I. Morino, K. M. T. Yamada, K. Tanaka. Detection of the tunneling-rotation transitions of malonaldehyde in the submillimeter-wave region. J. Chem. Phys., 110. 4131-4133 (1999) P. Turner, S. L. Baughcum, S. L. Coy, Z. Smith. Microwave Spectroscopic Study of Malonaldehyde. 4. Vibration-Rotation Interaction in Parent Species. J. Am. Chem. Soc., 106. 2265-2267 (1984) D. W. Firth, K. Beyer, M. A. Dvorak, S. W. Reeve, A. Grushow, K. R. Leopold. Tunable far-infrared spectroscopy of malonaldehyde. J. Chem. Phys., 94. 1812

  18. Vibrational and Rotational Spectroscopy of CD_2H^+

    NASA Astrophysics Data System (ADS)

    Asvany, Oskar; Jusko, Pavol; Brünken, Sandra; Schlemmer, Stephan

    2016-06-01

    The lowest rotational levels (J=0-5) of the CD_2H^+ ground state have been probed by high-resolution rovibrational and pure rotational spectroscopy in a cryogenic 22-pole ion trap. For this, the ν_1 rovibrational band has been revisited, detecting 107 transitions, among which 35 are new. The use of a frequency comb system allowed to measure the rovibrational transitions with high precision and accuracy, typically better than 1 MHz. The high precision has been confirmed by comparing combination differences in the ground and vibrationally excited state. For the ground state, this allowed for equally precise predictions of pure rotational transitions, 24 of which have been measured directly by a novel IR - mm-wave double resonance method. M.-F. Jagod et al, J. Molec. Spectrosc. 153, 666, 1992 S. Gartner et al, J. Phys. Chem. A 117, 9975, 2013

  19. 48 CFR 47.306-2 - Lowest overall transportation costs.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... transportation costs. 47.306-2 Section 47.306-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.306-2 Lowest overall transportation costs. (a) For the evaluation of offers, the transportation officer shall give to the contracting...

  20. 48 CFR 47.306-2 - Lowest overall transportation costs.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... transportation costs. 47.306-2 Section 47.306-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.306-2 Lowest overall transportation costs. (a) For the evaluation of offers, the transportation officer shall give to the contracting...

  1. 48 CFR 47.306-2 - Lowest overall transportation costs.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Lowest overall transportation costs. 47.306-2 Section 47.306-2 Federal Acquisition Regulations System FEDERAL ACQUISITION... and incidental charges that (1) are in effect on, or become effective before, the expected date of the...

  2. 20. WINE CELLAR This is the lowest room in the ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    20. WINE CELLAR This is the lowest room in the house, under the service entrance from S Street. Note reinforced concrete floor slab above (reinforced concrete floor slabs were used throughout the house). - Woodrow Wilson House, 2340 South S Street, Northwest, Washington, District of Columbia, DC

  3. 48 CFR 47.306-2 - Lowest overall transportation costs.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... transportation costs. 47.306-2 Section 47.306-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.306-2 Lowest overall transportation costs. (a) For the evaluation of offers, the transportation officer shall give to the contracting...

  4. 48 CFR 47.306-2 - Lowest overall transportation costs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... transportation costs. 47.306-2 Section 47.306-2 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT MANAGEMENT TRANSPORTATION Transportation in Supply Contracts 47.306-2 Lowest overall transportation costs. (a) For the evaluation of offers, the transportation officer shall give to the contracting...

  5. Towards rotationally state-resolved differential cross sections for the hydrogen exchange reaction

    SciTech Connect

    Vrakking, Marcus Johannes Jacobus

    1992-11-01

    The hydrogen exchange reaction H + H2 → H2 + H (and its isotopic variants) plays a pivotal role in chemical reaction dynamics. It is the only chemical reaction for which fully converged quantum scattering calculations have been carried out using a potential energy surface which is considered to be chemically accurate. To improve our ability to test the theory, a `perfect experiment`, measuring differential cross sections with complete specification of the reactant and product states, is called for. In this thesis, the design of an experiment is described that aims at achieving this goal for the D + H2 reaction. A crossed molecular beam arrangement is used, in which a photolytic D atom beam is crossed by a pulsed beam of H2 molecules. DH molecules formed in the D + H2 reaction are state-specifically ionized using Doppler-free (2+1) Resonance-Enhanced Multi-Photon Ionization (REMPI) and detected using a Position-sensitive microchannel plate detector. This detection technique has an unprecedented single shot detection sensitivity of 6.8 103 molecules/cc. This thesis does not contain experimental results for the D + H2 reaction yet, but progress that has been made towards achieving this goal is reported. In addition, results are reported for a study of the Rydberg spectroscopy of the water molecule.

  6. Towards rotationally state-resolved differential cross sections for the hydrogen exchange reaction

    SciTech Connect

    Vrakking, M.J.J.

    1992-11-01

    The hydrogen exchange reaction H + H[sub 2] [yields] H[sub 2] + H (and its isotopic variants) plays a pivotal role in chemical reaction dynamics. It is the only chemical reaction for which fully converged quantum scattering calculations have been carried out using a potential energy surface which is considered to be chemically accurate. To improve our ability to test the theory, a 'perfect experiment', measuring differential cross sections with complete specification of the reactant and product states, is called for. In this thesis, the design of an experiment is described that aims at achieving this goal for the D + H[sub 2] reaction. A crossed molecular beam arrangement is used, in which a photolytic D atom beam is crossed by a pulsed beam of H[sub 2] molecules. DH molecules formed in the D + H[sub 2] reaction are state-specifically ionized using Doppler-free (2+1) Resonance-Enhanced Multi-Photon Ionization (REMPI) and detected using a Position-sensitive microchannel plate detector. This detection technique has an unprecedented single shot detection sensitivity of 6.8 10[sup 3] molecules/cc. This thesis does not contain experimental results for the D + H[sub 2] reaction yet, but progress that has been made towards achieving this goal is reported. In addition, results are reported for a study of the Rydberg spectroscopy of the water molecule.

  7. A hybrid fault diagnosis approach based on mixed-domain state features for rotating machinery.

    PubMed

    Xue, Xiaoming; Zhou, Jianzhong

    2017-01-01

    To make further improvement in the diagnosis accuracy and efficiency, a mixed-domain state features data based hybrid fault diagnosis approach, which systematically blends both the statistical analysis approach and the artificial intelligence technology, is proposed in this work for rolling element bearings. For simplifying the fault diagnosis problems, the execution of the proposed method is divided into three steps, i.e., fault preliminary detection, fault type recognition and fault degree identification. In the first step, a preliminary judgment about the health status of the equipment can be evaluated by the statistical analysis method based on the permutation entropy theory. If fault exists, the following two processes based on the artificial intelligence approach are performed to further recognize the fault type and then identify the fault degree. For the two subsequent steps, mixed-domain state features containing time-domain, frequency-domain and multi-scale features are extracted to represent the fault peculiarity under different working conditions. As a powerful time-frequency analysis method, the fast EEMD method was employed to obtain multi-scale features. Furthermore, due to the information redundancy and the submergence of original feature space, a novel manifold learning method (modified LGPCA) is introduced to realize the low-dimensional representations for high-dimensional feature space. Finally, two cases with 12 working conditions respectively have been employed to evaluate the performance of the proposed method, where vibration signals were measured from an experimental bench of rolling element bearing. The analysis results showed the effectiveness and the superiority of the proposed method of which the diagnosis thought is more suitable for practical application. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

  8. A theoretical perspective on the accuracy of rotational resonance (R 2)-based distance measurements in solid-state NMR

    NASA Astrophysics Data System (ADS)

    Pandey, Manoj Kumar; Ramachandran, Ramesh

    2010-03-01

    The application of solid-state NMR methodology for bio-molecular structure determination requires the measurement of constraints in the form of 13C-13C and 13C-15N distances, torsion angles and, in some cases, correlation of the anisotropic interactions. Since the availability of structurally important constraints in the solid state is limited due to lack of sufficient spectral resolution, the accuracy of the measured constraints become vital in studies relating the three-dimensional structure of proteins to its biological functions. Consequently, the theoretical methods employed to quantify the experimental data become important. To accentuate this aspect, we re-examine analytical two-spin models currently employed in the estimation of 13C-13C distances based on the rotational resonance (R 2) phenomenon. Although the error bars for the estimated distances tend to be in the range 0.5-1.0 Å, R 2 experiments are routinely employed in a variety of systems ranging from simple peptides to more complex amyloidogenic proteins. In this article we address this aspect by highlighting the systematic errors introduced by analytical models employing phenomenological damping terms to describe multi-spin effects. Specifically, the spin dynamics in R 2 experiments is described using Floquet theory employing two different operator formalisms. The systematic errors introduced by the phenomenological damping terms and their limitations are elucidated in two analytical models and analysed by comparing the results with rigorous numerical simulations.

  9. A stationary north-finding scheme for an azimuth rotational IMU utilizing a linear state equality constraint.

    PubMed

    Yu, Huapeng; Zhu, Hai; Gao, Dayuan; Yu, Meng; Wu, Wenqi

    2015-02-13

    The Kalman filter (KF) has always been used to improve north-finding performance under practical conditions. By analyzing the characteristics of the azimuth rotational inertial measurement unit (ARIMU) on a stationary base, a linear state equality constraint for the conventional KF used in the fine north-finding filtering phase is derived. Then, a constrained KF using the state equality constraint is proposed and studied in depth. Estimation behaviors of the concerned navigation errors when implementing the conventional KF scheme and the constrained KF scheme during stationary north-finding are investigated analytically by the stochastic observability approach, which can provide explicit formulations of the navigation errors with influencing variables. Finally, multiple practical experimental tests at a fixed position are done on a postulate system to compare the stationary north-finding performance of the two filtering schemes. In conclusion, this study has successfully extended the utilization of the stochastic observability approach for analytic descriptions of estimation behaviors of the concerned navigation errors, and the constrained KF scheme has demonstrated its superiority over the conventional KF scheme for ARIMU stationary north-finding both theoretically and practically.

  10. A new accurate ground-state potential energy surface of ethylene and predictions for rotational and vibrational energy levels.

    PubMed

    Delahaye, Thibault; Nikitin, Andrei; Rey, Michaël; Szalay, Péter G; Tyuterev, Vladimir G

    2014-09-14

    In this paper we report a new ground state potential energy surface for ethylene (ethene) C2H4 obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82,542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C2H4 molecule was obtained with a RMS(Obs.-Calc.) deviation of 2.7 cm(-1) for fundamental bands centers and 5.9 cm(-1) for vibrational bands up to 7800 cm(-1). Large scale vibrational and rotational calculations for (12)C2H4, (13)C2H4, and (12)C2D4 isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm(-1) are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of (13)C2H4 and (12)C2D4 and rovibrational levels of (12)C2H4.

  11. A Stationary North-Finding Scheme for an Azimuth Rotational IMU Utilizing a Linear State Equality Constraint

    PubMed Central

    Yu, Huapeng; Zhu, Hai; Gao, Dayuan; Yu, Meng; Wu, Wenqi

    2015-01-01

    The Kalman filter (KF) has always been used to improve north-finding performance under practical conditions. By analyzing the characteristics of the azimuth rotational inertial measurement unit (ARIMU) on a stationary base, a linear state equality constraint for the conventional KF used in the fine north-finding filtering phase is derived. Then, a constrained KF using the state equality constraint is proposed and studied in depth. Estimation behaviors of the concerned navigation errors when implementing the conventional KF scheme and the constrained KF scheme during stationary north-finding are investigated analytically by the stochastic observability approach, which can provide explicit formulations of the navigation errors with influencing variables. Finally, multiple practical experimental tests at a fixed position are done on a postulate system to compare the stationary north-finding performance of the two filtering schemes. In conclusion, this study has successfully extended the utilization of the stochastic observability approach for analytic descriptions of estimation behaviors of the concerned navigation errors, and the constrained KF scheme has demonstrated its superiority over the conventional KF scheme for ARIMU stationary north-finding both theoretically and practically. PMID:25688588

  12. Bound state potential energy surface construction: ab initio zero-point energies and vibrationally averaged rotational constants.

    PubMed

    Bettens, Ryan P A

    2003-01-15

    Collins' method of interpolating a potential energy surface (PES) from quantum chemical calculations for reactive systems (Jordan, M. J. T.; Thompson, K. C.; Collins, M. A. J. Chem. Phys. 1995, 102, 5647. Thompson, K. C.; Jordan, M. J. T.; Collins, M. A. J. Chem. Phys. 1998, 108, 8302. Bettens, R. P. A.; Collins, M. A. J. Chem. Phys. 1999, 111, 816) has been applied to a bound state problem. The interpolation method has been combined for the first time with quantum diffusion Monte Carlo calculations to obtain an accurate ground state zero-point energy, the vibrationally average rotational constants, and the vibrationally averaged internal coordinates. In particular, the system studied was fluoromethane using a composite method approximating the QCISD(T)/6-311++G(2df,2p) level of theory. The approach adopted in this work (a) is fully automated, (b) is fully ab initio, (c) includes all nine nuclear degrees of freedom, (d) requires no assumption of the functional form of the PES, (e) possesses the full symmetry of the system, (f) does not involve fitting any parameters of any kind, and (g) is generally applicable to any system amenable to quantum chemical calculations and Collins' interpolation method. The calculated zero-point energy agrees to within 0.2% of its current best estimate. A0 and B0 are within 0.9 and 0.3%, respectively, of experiment.

  13. Implementing the Extended School Day Policy in Florida's 300 Lowest Performing Elementary Schools. REL 2017-253

    ERIC Educational Resources Information Center

    Folsom, Jessica Sidler; Osborne-Lampkin, La'Tara; Cooley, Stephan; Smith, Kevin

    2017-01-01

    Since the 2012/13 school year Florida law has required the 100 lowest performing elementary schools in reading to extend the school day by one hour to provide supplemental reading instruction. In 2014 the law was broadened to include the 300 elementary schools with the lowest reading performance. A previous study of the state's first two cohorts…

  14. On the ground states and dynamics of space fractional nonlinear Schrödinger/Gross-Pitaevskii equations with rotation term and nonlocal nonlinear interactions

    NASA Astrophysics Data System (ADS)

    Antoine, Xavier; Tang, Qinglin; Zhang, Yong

    2016-11-01

    In this paper, we propose some efficient and robust numerical methods to compute the ground states and dynamics of Fractional Schrödinger Equation (FSE) with a rotation term and nonlocal nonlinear interactions. In particular, a newly developed Gaussian-sum (GauSum) solver is used for the nonlocal interaction evaluation [31]. To compute the ground states, we integrate the preconditioned Krylov subspace pseudo-spectral method [4] and the GauSum solver. For the dynamics simulation, using the rotating Lagrangian coordinates transform [14], we first reformulate the FSE into a new equation without rotation. Then, a time-splitting pseudo-spectral scheme incorporated with the GauSum solver is proposed to simulate the new FSE. In parallel to the numerical schemes, we also prove some existence and nonexistence results for the ground states. Dynamical laws of some standard quantities, including the mass, energy, angular momentum and the center of mass, are stated. The ground states properties with respect to the fractional order and/or rotating frequencies, dynamics involving decoherence and turbulence together with some interesting phenomena are reported.

  15. Lowest energy Frenkel and charge transfer exciton intermixing in one-dimensional copper phthalocyanine molecular lattice

    NASA Astrophysics Data System (ADS)

    Bondarev, I. V.; Popescu, A.; Younts, R. A.; Hoffman, B.; McAfee, T.; Dougherty, D. B.; Gundogdu, K.; Ade, H. W.

    2016-11-01

    We report the results of the combined experimental and theoretical studies of the low-lying exciton states in crystalline copper phthalocyanine. We derive the eigen energy spectrum for the two lowest intramolecular Frenkel excitons coupled to the intermolecular charge transfer exciton state and compare it with temperature dependent optical absorption spectra measured experimentally, to obtain the parameters of the Frenkel-charge-transfer exciton intermixing. The two Frenkel exciton states are spaced apart by 0.26 eV, and the charge transfer exciton state is 50 meV above the lowest Frenkel exciton. Both Frenkel excitons are strongly mixed with the charge transfer exciton, showing the coupling constant 0.17 eV which agrees with earlier experimental measurements. These results can be used for the proper interpretation of the physical properties of crystalline phthalocyanines.

  16. Steric asymmetry and lambda-doublet propensities in state-to-state rotationally inelastic scattering of NO (2 pi 1/2) with He.

    SciTech Connect

    Wiskerke, Arjan E.; de Lange, Marc J.L.; Stolte, Steven; Taatjes, Craig A.; van der Avoird, Ad; Klos, Jacek

    2004-08-01

    Relative integrated cross sections are measured for rotationally inelastic scattering of NO({sup 2}{pi}{sub 1/2}), hexapole selected in the upper {Lambda}-doublet level of the ground rotational state (j = 0.5), in collisions with He at a nominal energy of 514 cm{sup -1}. Application of a static electric field E in the scattering region, directed parallel or antiparallel to the relative velocity vector v, allows the state-selected NO molecule to be oriented with either the N end or the O end towards the incoming He atom. Laser-induced fluorescence detection of the final state of the NO molecule is used to determine the experimental steric asymmetry, SA {triple_bond} ({sigma}{sub v}{up_arrow}{down_arrow}{sub E}-{sigma}{sub v}{up_arrow}{up_arrow}{sub E})/({sigma}{sub v}{up_arrow}{down_arrow}{sub E} + {sigma}{sub v}{up_arrow}{up_arrow}{sub E}), which is equal to within a factor of (-1) to the molecular steric effect, S{sub i {yields} f} {triple_bond} ({sigma}{sub He {yields} NO} - {sigma}{sub He {yields} ON})/({sigma}{sub He {yields} NO} + {sigma}{sub He {yields} ON}). The dependence of the integral inelastic cross section on the incoming {lambda}-doublet component is also observed as a function of the final rotational (j{prime}), spin-orbit ({Omega}{prime}), and {Lambda}-doublet ({epsilon}{prime}) state. The measured steric asymmetries are significantly larger than previously observed for NO-Ar scattering, supporting earlier proposals that the repulsive part of the interaction potential is responsible for the steric asymmetry. In contrast to the case of scattering with Ar, the steric asymmetry of NO-He collisions is not very sensitive to the value of {Omega}{prime} . However, the {Lambda}-doublet propensities are very different for [{Omega} = 0.5(F{sub 1}) {yields} {Omega}{prime} = 0.5(F{sub 1})] transitions. Spin-orbit manifold conserving collisions exhibit a propensity for parity conservation at low {Delta}{sub j}, but spin-orbit manifold changing collisions do not

  17. Steric asymmetry and lambda-doublet propensities in state-to-state rotationally inelastic scattering of NO(2Π1/2) with He

    NASA Astrophysics Data System (ADS)

    de Lange, Marc J. L.; Stolte, Steven; Taatjes, Craig A.; Kłos, Jacek; Groenenboom, Gerrit C.; van der Avoird, Ad

    2004-12-01

    Relative integrated cross sections are measured for rotationally inelastic scattering of NO(2Π1/2), hexapole selected in the upper Λ-doublet level of the ground rotational state (j=0.5), in collisions with He at a nominal energy of 514 cm-1. Application of a static electric field E in the scattering region, directed parallel or antiparallel to the relative velocity vector v, allows the state-selected NO molecule to be oriented with either the N end or the O end towards the incoming He atom. Laser-induced fluorescence detection of the final state of the NO molecule is used to determine the experimental steric asymmetry, SA≡(σv↑↓E-σv↑↑E)/(σv↑↓E+σv↑↑E), which is equal to within a factor of (-1) to the molecular steric effect, Si→f≡(σHe→NO-σHe→ON)/(σHe→NO+σHe→ON). The dependence of the integral inelastic cross section on the incoming Λ-doublet component is also observed as a function of the final rotational (j'), spin-orbit (Ω'), and Λ-doublet (ɛ') state. The measured steric asymmetries are significantly larger than previously observed for NO-Ar scattering, supporting earlier proposals that the repulsive part of the interaction potential is responsible for the steric asymmetry. In contrast to the case of scattering with Ar, the steric asymmetry of NO-He collisions is not very sensitive to the value of Ω'. However, the Λ-doublet propensities are very different for [Ω=0.5(F1)→Ω'=1.5(F2)] and [Ω=0.5(F1)→Ω'=0.5(F1)] transitions. Spin-orbit manifold conserving collisions exhibit a propensity for parity conservation at low Δj, but spin-orbit manifold changing collisions do not show this propensity. In conjunction with the experiments, state-to-state cross sections for scattering of oriented NO(2Π) molecules with He atoms are predicted from close-coupling calculations on restricted coupled-cluster methods including single, double, and noniterated triple excitations [J. Klos, G. Chalasinski, M. T. Berry, R. Bukowski, and

  18. Terahertz vibration-rotation-tunneling spectroscopy of the ammonia dimer. II. A-E states of an out-of-plane vibration and an in-plane vibration.

    PubMed

    Lin, Wei; Han, Jia-Xiang; Takahashi, Lynelle K; Loeser, Jennifer G; Saykally, Richard J

    2007-10-04

    Terahertz vibration-rotation-tunneling transitions have been measured between ca. 78.5 and 91.9 cm-1, and assigned to A-E (ortho-para) combinations of NH3 monomer states. The spectrum is complicated by inversion splittings that correlate to E symmetry monomer rovibronic states. Twenty progressions have been assigned to six excited states involving an out-of-plane vibration and an in-plane intermolecular vibration. The quality of the fit was affected by strong Coriolis interactions among these states and possibly an additional K = 2 state that was not explicitly observed in the data.

  19. Impact of individualized learning plans on United States senior medical students advanced clinical rotations.

    PubMed

    Guardiola, Amalia; Barratt, Michelle S; Omoruyi, Emma A

    2016-01-01

    The individualized learning plan (ILP) is a tool that promotes self-directed learning. The aim of this pilot study was to look at the perception of the ILPs in United States senior medical school students as a way to improve their learning experience during their advanced practice clerkship. We conducted a survey of graduating medical students that contained both quantitative and open-ended questions regarding the students' experiences with the ILP during their advanced practice clerkship from July 2014 to March 2016. We systematically identified and compiled themes among the qualitative responses. Responses from 294 out of 460 subjects were included for analysis (63.9%). Ninety students (30.6%) reported that the ILP was definitely reviewed at the midpoint and 88 (29.9%) at the final evaluation. One hundred sixty one students (54.8%) felt the ILP provided a framework for learning. One hundred sixty one students (61.6%) felt it was a useful tool in helping open a discussion between the student and faculty. The qualitative data was grouped by areas most mentioned and these areas of concern centered on lack of faculty knowledge about ILP, time to complete ILP, and uncertainty of appropriate goal setting. The majority of students perceive the ILP to be helpful. Our results suggest that active intervention is needed by dedicated and trained faculty to improve ILP utilization. It is recommended that faculty gives students examples of learning goals to create their own learning framework and encourages them to discuss and review the ILP.

  20. Exploring the Galactic Cosmic Rays at the lowest energies

    NASA Astrophysics Data System (ADS)

    Shapiro, M. M.

    2001-08-01

    The solar wind prevents the lowest-energy Galactic cosmic rays (GCR) from entering the Heliosphere. Consequently, space probes have thus far been unable to sample them. We suggest that astrochemistry may provide a handle on these particles. Clouds in the interstellar medium (ISM) are sites of chemical-reaction networks that produce various molecular species detectable by their radioastronomical signatures. Highly ionizing low-energy cosmic rays are thought to be the principal agents of molecule production in clouds. Some anomalous abundances, e.g., of deuterium molecules, have been detected. Could studies of the foregoing networks of reactions and their products yield clues to the fluxes and energy spectra of the lowest-energy GCR in the ISM? Other approaches to this problem are also cited.

  1. Economic potential of short-rotation woody crops on agricultural land for pulp fiber production in the United States.

    Treesearch

    Ralph J. Alig; Darius M. Adams; Bruce A. McCarl; Peter J. Ince

    2000-01-01

    A model of the U.S. forestry and agricultural sectors is used to simulate the consequences of growing short-rotation woody crops on agricultural lands as a fiber source for pulp and paper production. Hybrid poplar, a short-rotation woody crop, annually produces 4 to 7 dry tons per acre of hardwood pulpwood over a 6- to 10-year rotation. When harvested, the material...

  2. The rotational spectrum of the cyclopentadienylallylnickel complex

    NASA Astrophysics Data System (ADS)

    Tanjaroon, Chakree; Sebonia, Matthew; Kukolich, Stephen G.

    2008-03-01

    The rotational spectrum of cyclopentadienylallylnickel, C 3H 5NiC 5H 5, has been studied using a pulsed molecular beam Fourier transform microwave spectrometer. Twelve a-type transitions were analyzed to obtain rotational and centrifugal distortion constants for the parent C 3H 558NiC 5H 5 complex. The measured rotational constant A = 3107.603(93) MHz is about 160.0 MHz larger than the predicted DFT value, providing evidence for possible fluxional motion in the complex. The large distortion constants, on the order of 100 kHz, provide further evidence for fluxional motion. The experimental constants B = 1302.38(22) and C = 1276.40(15) MHz are in good agreement with the DFT calculated values and confirm the η 3-bonding of the allyl ligand to the Ni-C 5H 5 moiety. DFT calculations provide a V 5 barrier for internal rotation about the Ni-C 5H 5 axis of 53 cm -1, with the lowest energy conformation having the central allyl c-atom eclipsed with respect to two C 5H 5 carbon atoms. Several additional rotational lines, possibly those of an exited torsional state, were observed but not assigned.

  3. Electric dipole moment function of the X1 Sigma/+/ state of CO - Vibration-rotation matrix elements for transitions of gas laser and astrophysical interest

    NASA Technical Reports Server (NTRS)

    Chackerian, C., Jr.

    1976-01-01

    The electric dipole moment function of the ground electronic state of carbon monoxide has been determined by combining numerical solutions of the radial Schrodinger equation with absolute intensity data of vibration-rotation bands. The derived dipole moment function is used to calculate matrix elements of interest to stellar astronomy and of importance in the carbon monoxide laser.

  4. Changes of crop rotation in Iowa determined from the United States Department of Agriculture, National Agricultural Statistics Service cropland data layer product

    NASA Astrophysics Data System (ADS)

    Stern, Alan J.; Doraiswamy, Paul C.; Raymond Hunt, E.

    2012-01-01

    Crop rotation is one of the important decisions made independently by numerous farm managers, and is a critical variable in models of crop growth and soil carbon. In Iowa and much of the Midwestern United States (US), the typical management decision is to rotate corn and soybean crops for a single field; therefore, the land-cover changes each year even though the total area of agricultural land-use remains the same. The price for corn increased from 2001 to 2010, which increased corn production in Iowa. We tested the hypothesis that the production increase was the result of changes in crop rotation in Iowa using the annual remote sensing classification (the cropland data layer) produced by the United States Department of Agriculture, National Agricultural Statistics Service. It was found that the area planted in corn increased from 4.7 million hectares in 2001 to 5.7 million hectares in 2007, which was correlated with the market price for corn. At the county level, there were differences in how the increase in corn production was accomplished. Northern and central counties had little land to expand cultivation and generally increased corn production by converting to a corn-corn rotation from the standard corn-soybean rotation. Southern counties in Iowa increased corn production by expanding into land that was not under recent cultivation. These changes affect the amount of soil carbon sequestration.

  5. Rotationally resolved state-to-state photoionization and photoelectron study of titanium carbide and its cation (TiC/TiC{sup +})

    SciTech Connect

    Luo, Zhihong; Huang, Huang; Chang, Yih-Chung; Zhang, Zheng; Ng, C. Y.; Yin, Qing-Zhu

    2014-10-14

    Titanium carbide and its cation (TiC/TiC{sup +}) have been investigated by the two-color visible (VIS)-ultraviolet (UV) resonance-enhanced photoionization and pulsed field ionization-photoelectron (PFI-PE) methods. Two visible excitation bands for neutral TiC are observed at 16 446 and 16 930 cm{sup −1}. Based on rotational analyses, these bands are assigned as the respective TiC({sup 3}Π{sub 1}) ← TiC(X{sup 3}Σ{sup +}) and TiC({sup 3}Σ{sup +}) ← TiC(X{sup 3}Σ{sup +}) transition bands. This assignment supports that the electronic configuration and term symmetry for the neutral TiC ground state are …7σ{sup 2}8σ{sup 1}9σ{sup 1}3π{sup 4} (X{sup 3}Σ{sup +}). The rotational constant and the corresponding bond distance of TiC(X{sup 3}Σ{sup +}; v″ = 0) are determined to be B{sub 0}″ = 0.6112(10) cm{sup −1} and r{sub 0}″ = 1.695(2) Å, respectively. The rotational analyses of the VIS-UV-PFI-PE spectra for the TiC{sup +}(X; v{sup +} = 0 and 1) vibrational bands show that the electronic configuration and term symmetry for the ionic TiC{sup +} ground state are …7σ{sup 2}8σ{sup 1}3π{sup 4} (X{sup 2}Σ{sup +}) with the v{sup +} = 0 → 1 vibrational spacing of 870.0(8) cm{sup −1} and the rotational constants of B{sub e}{sup +} = 0.6322(28) cm{sup −1}, and α{sub e}{sup +} = 0.0085(28) cm{sup −1}. The latter rotational constants yield the equilibrium bond distance of r{sub e}{sup +} = 1.667(4) Å for TiC{sup +}(X{sup 2}Σ{sup +}). The cleanly rotationally resolved VIS-UV-PFI-PE spectra have also provided a highly precise value of 53 200.2(8) cm{sup −1} [6.5960(1) eV] for the adiabatic ionization energy (IE) of TiC. This IE(TiC) value along with the known IE(Ti) has made possible the determination of the difference between the 0 K bond dissociation energy (D{sub 0}) of TiC{sup +}(X{sup 2}Σ{sup +}) and that of TiC(X{sup 3}Σ{sup +}) to be D{sub 0}(Ti{sup +}−C) − D{sub 0}(Ti−C) = 0.2322(2) eV. Similar to previous experimental

  6. Direct determination of state-to-state rotational energy transfer rate constants via a Raman-Raman double resonance technique: ortho-acetylene in v(2)=1 at 155 K.

    PubMed

    Doménech, José L; Martínez, Raúl Z; Ramos, Angel; Bermejo, Dionisio

    2010-04-21

    A new technique for the direct determination of state-to-state rotational energy transfer rate constants in the gas phase is presented. It is based on two sequential stimulated Raman processes: the first one prepares the sample in a single rotational state of an excited vibrational level, and the second one, using the high resolution quasi-continuous stimulated Raman-loss technique, monitors the transfer of population to other rotational states of the same vibrational level as a function of the delay between the pump and the probe stages. The technique is applied to the odd-J rotational states of v(2)=1 acetylene at 155 K. The experimental layout, data acquisition, retrieval procedures, and numerical treatment are described. The quantity and quality of the data are high enough to allow a direct determination of the state-to-state rate constant matrix from a fit of the experimental data, with the only conditions of detailed balance and of a closed number of states. The matrix obtained from this direct fit is also compared with those obtained using some common fitting and scaling laws.

  7. Sum Frequency Generation Spectroscopy and Molecular Dynamics Simulations Reveal a Rotationally Fluid Adsorption State of α-Pinene on Silica

    SciTech Connect

    Ho, Junming; Psciuk, Brian T.; Chase, Hilary M.; Rudshteyn, Benjamin; Upshur, Mary Alice; Fu, Li; Thomson, Regan J.; Wang, Hong-Fei; Geiger, Franz M.; Batista, Victor S.

    2016-06-16

    A rotationally fluid state of α-pinene at fused silica/vapor interfaces is revealed by computational and experimental vibrational sum frequency generation (SFG) studies. We report the first assignment of the vibrational modes in the notoriously congested C-H stretching region of α-pinene and identify its bridge methylene group on the four-membered ring ("βCH2") as the origin of its dominant spectral feature. We find that the spectra are perfused with Fermi resonances that need to be accounted for explicitly in the computation of vibrational spectra of strained hydrocarbons such α-pinene. The preferred orientations of α-pinene are consistent with optimization of van der Waals contacts with the silica surface that results in a bimodal distribution of highly fluxional orientations in which the βCH2 group points "towards" or "away from” the surface. The reported findings are particularly relevant to the exposure of α-pinene to primary oxidants in heterogeneous catalytic pathways that exploit α-pinene as a sustainable feedstock for fine chemicals and polymers.

  8. Rotational resonance for a heteronuclear spin pair under magic-angle spinning in solid-state NMR

    NASA Astrophysics Data System (ADS)

    Kamihara, Takayuki; Takegoshi, K.

    2017-04-01

    Rotational resonance (R2) is one of the widely applied techniques in solid-state NMR for recoupling a homonuclear dipolar interaction under magic-angle spinning (MAS). R2 occurs as the result of interference between the difference of the chemical shifts and MAS. In this work, we extend R2 to a heteronuclear dipolar interaction in the interaction frame of RF irradiation. Based on the average Hamiltonian theory, we show that the recoupling of the heteronuclear dipolar (I-S) interaction occurs at the recoupling conditions written as ΩI'±ΩS' =k ωr (k =0 ,±1 ,±2 ), where ΩX' is the RF offset for spin-X (X = I or S) scaled by RF irradiation. The new recoupling sequence for a heteronuclear spin pair is referred to as offset-driven cross polarization along the z axis (OD-CPZ). With the robustness for RF inhomogeneity and ten recoupling conditions to choose, OD-CPZ can be a useful frequency-selective cross polarization method. Experiments and numerical simulations are shown with the results of the theoretical analysis.

  9. The Sc+NO→ScO+N reaction: Rotational state distribution in ScOX 2Σ+(v″=0)

    NASA Astrophysics Data System (ADS)

    Luc, P.; Vetter, R.

    2001-12-01

    The Sc+NO→ScO+N reaction has been investigated in a beam-gas arrangement, with characterization of ScO products by cw laser-induced fluorescence: absorption versus laser frequency over the A 2Π(v'=1)-X2Σ+(v″=0) band and fluorescence over the A 2Π(v'=1)-X2Σ+(v″=1) one. It leads to the direct determination of the nascent rotational state distribution in the X 2Σ+(v″=0) level of ScO. This distribution is close to a Prior statistical one, with a well-characterized weak "surprisal," indicating that a momentum constraint takes place during the reaction process. In the frame of this statistical distribution, a new accurate value for the dissociation energy of ScO is proposed: D00(ScO)=(6.92±0.01) eV. Spectroscopic data are reported for the A 2Π(v'=1)-X 2Σ+(v=0) band, up to N=98.

  10. An approximate global solution of Einstein's equation for a rotating compact source with linear equation of state

    NASA Astrophysics Data System (ADS)

    Cuchí, J. E.; Gil-Rivero, A.; Molina, A.; Ruiz, E.

    2013-07-01

    We use analytic perturbation theory to present a new approximate metric for a rigidly rotating perfect fluid source with equation of state (EOS) ɛ +(1-n)p=ɛ _0. This EOS includes the interesting cases of strange matter, constant density and the fluid of the Wahlquist metric. It is fully matched to its approximate asymptotically flat exterior using Lichnerowicz junction conditions and it is shown to be a totally general matching using Darmois-Israel conditions and properties of the harmonic coordinates. Then we analyse the Petrov type of the interior metric and show first that, in accordance with previous results, in the case corresponding to Wahlquist's metric it can not be matched to the asymptotically flat exterior. Next, that this kind of interior can only be of Petrov types I, D or (in the static case) O and also that the non-static constant density case can only be of type I. Finally, we check that it can not be a source of Kerr's metric.

  11. Rotation operator approach for the dynamics of non-dissipative multi-state Landau-Zener problems: Exact solutions

    NASA Astrophysics Data System (ADS)

    Ateuafack, M. E.; Diffo, J. T.; Fai, L. C.; Jipdi, M. N.

    2017-01-01

    The paper investigates exact time-dependent analytical solutions of the Landau-Zener (LZ) transitions for spin one-half subjected to classical noise field using rotation operator approach introduced by Zhou and co-authors. The particular case of the LZ model subjected to colored noise field is studied and extended to arbitrary spin magnitude. Transition probabilities are derived regardless of the initial configuration of the system and are found to be functions of the sort for Stokes constant. It is observed that the latter may be completely evaluated provided we have knowledge of the phase difference between noise in x - and y - directions. Transition probabilities are found to depend not only on the LZ parameter and noise frequency, but also on the states involved in the study. In particular, the coherence of the system is sustained for an exceedingly long time when many levels are considered in an atom and if in addition, the LZ parameter tends to unity and the noise' frequency is low.

  12. Rotator cuff tear state modulates self-renewal and differentiation capacity of human skeletal muscle progenitor cells.

    PubMed

    Thomas, Kelsey A; Gibbons, Michael C; Lane, John G; Singh, Anshuman; Ward, Samuel R; Engler, Adam J

    2017-08-01

    Full thickness rotator cuff tendon (RCT) tears have long-term effects on RC muscle atrophy and fatty infiltration, with lasting damage even after surgical tendon repair. Skeletal muscle progenitor cells (SMPs) are critical for muscle repair in response to injury, but the inability of RC muscles to recover from chronic RCT tear indicates possible deficits in repair mechanisms. Here we investigated if muscle injury state was a crucial factor during human SMP expansion and differentiation ex vivo. SMPs were isolated from muscles in patients with no, partial-thickness (PT), or full-thickness (FT) RCT tears. Despite using growth factors, physiological niche stiffness, and muscle-mimetic extracellular matrix (ECM) proteins, we found that SMPs isolated from human RC muscle with RCT tears proliferated slower but fused into myosin heavy chain (MHC)-positive myotubes at higher rates than SMPs from untorn RCTs. Proteomic analysis of RC muscle tissue revealed shifts in muscle composition with pathology, as muscle from massive RCT tears had increased ECM deposition compared with no tear RC muscle. Together these data imply that the remodeled niche in a torn RCT primes SMPs not for expansion but for differentiation, thus limiting longer-term self-renewal necessary for regeneration after surgical repair. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1816-1823, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  13. Rotational spectroscopy as a tool to investigate interactions between vibrational polyads in symmetric top molecules: Low-lying states v(8) <= 2 of methyl cyanide, CH3CN

    SciTech Connect

    Muller, H. S.; Brown, Linda R.; Drouin, B. J.; Pearson, J. C.; Kleiner, Isabelle; Sams, Robert L.; Sung, Keeyoon; Ordu, Matthias H.; Lewen, Frank

    2015-06-01

    Rotational and rovibrational spectra of methyl cyanide were recorded to analyze interactions in low-lying vibrational states and to construct line lists for radio astronomical observations as well as for infrared spectroscopic investigations of planetary atmospheres. The rotational spectra cover large portions of the 36-1627 GHz region. In the infrared (IR), a spectrum was recorded for this study in the region of 2v(8) around 717 cm(-1) with assignments covering 684-765 cm-1. Additional spectra in the vs region were used to validate the analysis.

  14. Far-Infrared Rotational Spectra of ZnH and ZnD in the X2Sigma+ (v = 0) State

    PubMed

    Tezcan; Varberg; Stroh; Evenson

    1997-10-01

    Several rotational transitions of zinc hydride and deuteride within the v = 0 level of the X2Sigma+ state have been measured in both electron spin components over the ranges N" = 2 to 10 for ZnH and N" = 9 to 21 for ZnD. A least-squares fit to these data in combination with low-N microwave data measured by other workers has resulted in improved values of the rotational, fine, and hyperfine structure constants. The values of the proton hyperfine constants are discussed in the context of a molecular orbital analysis of zinc hydride. Copyright 1997 Academic Press. Copyright 1997Academic Press

  15. Study of Dark-matter Admixed Neutron Stars Using the Equation of State from the Rotational Curves of Galaxies

    NASA Astrophysics Data System (ADS)

    Rezaei, Z.

    2017-01-01

    In this work, we employ the dark matter equations of state (DMEOSs) obtained from the rotational curves of galaxies as well as the fermionic DMEOS with m=1.0 {GeV} to study the structure of dark-matter admixed neutron stars (DMANSs). Applying the equation of state in the Skyrme framework for the neutron matter (NM), we calculate the mass–radius relation for different DMANSs with various DMEOSs and central pressure of dark matter (DM) to NM ratios. Our results show that for some DMEOSs, the mass–radius relations are in agreement with new observations, e.g., EXO 1745-248, 4U 1608-52, and 4U 1820-30, which are inconsistent with normal neutron stars. We conclude that both DMEOSs and central pressure ratios of DM to NM affect the slope of the mass–radius relation of DMANSs. This is because of the interaction between DM and NM, which leads to gravitationally or self-bound DMANSs. We study the radius of the NM sphere as well as the radius of the DM halo for different DMANSs. The results confirm that, in some cases, a NM sphere with a small radius is surrounded by a halo of DM with a larger radius. Our calculations verify that, due to the different degrees of DM domination in DMANSs, with a value of the visible radius of a star two possible DMANSs with different masses can exist. The gravitational redshift is also calculated for DMANSs with different DMEOSs and central pressure ratios. The results explain that the existence of DM in a DMANS leads to higher values of gravitational redshift of the star.

  16. A new accurate ground-state potential energy surface of ethylene and predictions for rotational and vibrational energy levels

    SciTech Connect

    Delahaye, Thibault Rey, Michaël Tyuterev, Vladimir G.; Nikitin, Andrei; Szalay, Péter G.

    2014-09-14

    In this paper we report a new ground state potential energy surface for ethylene (ethene) C{sub 2}H{sub 4} obtained from extended ab initio calculations. The coupled-cluster approach with the perturbative inclusion of the connected triple excitations CCSD(T) and correlation consistent polarized valence basis set cc-pVQZ was employed for computations of electronic ground state energies. The fit of the surface included 82 542 nuclear configurations using sixth order expansion in curvilinear symmetry-adapted coordinates involving 2236 parameters. A good convergence for variationally computed vibrational levels of the C{sub 2}H{sub 4} molecule was obtained with a RMS(Obs.–Calc.) deviation of 2.7 cm{sup −1} for fundamental bands centers and 5.9 cm{sup −1} for vibrational bands up to 7800 cm{sup −1}. Large scale vibrational and rotational calculations for {sup 12}C{sub 2}H{sub 4}, {sup 13}C{sub 2}H{sub 4}, and {sup 12}C{sub 2}D{sub 4} isotopologues were performed using this new surface. Energy levels for J = 20 up to 6000 cm{sup −1} are in a good agreement with observations. This represents a considerable improvement with respect to available global predictions of vibrational levels of {sup 13}C{sub 2}H{sub 4} and {sup 12}C{sub 2}D{sub 4} and rovibrational levels of {sup 12}C{sub 2}H{sub 4}.

  17. Vortex patterns in moderately rotating Bose-condensed gas

    NASA Astrophysics Data System (ADS)

    Imran, Mohd; Ahsan, M. A. H.

    2017-02-01

    Using exact diagonalization, we investigate the many-body ground state for regular vortex patterns in a rotating Bose-condensed gas of N spinless particles, confined in a quasi-two-dimensional harmonic trap and interacting repulsively via finite-range Gaussian potential. The N-body Hamiltonian matrix is diagonalized in given subspaces of quantized total angular momentum L z , to obtain the lowest-energy eigenstate. Further, the internal structure of these eigenstates is analyzed by calculating the corresponding conditional probability distribution. Specifically, the quantum mechanically stable as well as unstable states in a co-rotating frame are examined in the moderately rotating regime corresponding to angular momenta 4N≤slant {L}z< 5N for N = 16 bosons. In response to externally impressed rotation, the patterns of singly quantized vortices are formed, shaping into canonical polygons with a central vortex at the trap center. The internal structure of unstable states reveals the mechanism of entry, nucleation and pattern formation of vortices with structural phase transition, as the condensate goes from one stable vortical state to the other. The stable polygonal vortex patterns having discrete p-fold rotational symmetry with p = 5 and p = 6 are observed. The hexagonal vortex pattern with p = 6 symmetry is a precursor to the triangular vortex lattice of singly quantized vortices in the thermodynamic limit. For unstable states, quantum melting of vortex patterns due to uncertainty in positions of individual vortices, is also briefly discussed.

  18. Erratum - the Lowest Surface Brightness Disc Galaxy Known

    NASA Astrophysics Data System (ADS)

    Davies, J. I.; Phillipps, S.; Disney, M. J.

    1988-11-01

    The paper "The lowest surface brightness disc galaxy known' by J.I. Davies, S. Phillipps and M.J. Disney was published in Mon. Not. R. astr. Soc. (1988), 231, 69p. The declination of the object given in section 2 of the paper is incorrect and should be changed to +19^deg^48'23". Thus the object cannot be identified with GP 1444 as in the original paper. To minimize confusion we propose to refer to the low surface brightness galaxy as GP 1444A.

  19. Dynamics of momentum entanglement in lowest-order QED

    SciTech Connect

    Lamata, L.; Leon, J.; Solano, E.

    2006-01-15

    We study the dynamics of momentum entanglement generated in the lowest-order QED interaction between two massive spin-(1/2) charged particles, which grows in time as the two fermions exchange virtual photons. We observe that the degree of generated entanglement between interacting particles with initial well-defined momentum can be infinite. We explain this divergence in the context of entanglement theory for continuous variables, and show how to circumvent this apparent paradox. Finally, we discuss two different possibilities of transforming momentum into spin entanglement, through dynamical operations or through Lorentz boosts.

  20. Effects of rotational states on the c/a ratio in solid hydrogens

    SciTech Connect

    Strzhemechny, Mikhail A.; Hemley, Russell J.

    2015-04-08

    We propose an approach to the problem of lattice distortions at low temperatures and ambient pressure in the solid hydrogens in their rotational ground states that explicitly accounts for the molecular nature of the constituent particles. The model is based on the idea that the second-order rotation-related correction to the ground-state energy depends on the lattice parameters. The calculated ground-state rotation-related contributions, δgs = c/a–(8/3)1/2, are negative for all species, amounting to about –1.5×10–5 for H2 and D2, whereas for HD this contribution is about –0.6×10–3, which is roughly 50 times larger. This substantial difference stems from the fact that the rotational dynamics in the homonuclear solids and in HD differ appreciably. Furthermore, the approach can be generalized to high pressures.

  1. Spectroscopic study on deuterated benzenes. II. High-resolution laser spectroscopy and rotational structure in the S{sub 1} state

    SciTech Connect

    Kunishige, Sachi; Katori, Toshiharu; Baba, Masaaki; Hayashi, Masato; Hasegawa, Hirokazu; Ohshima, Yasuhiro

    2015-12-28

    High-resolution spectra of the S{sub 1}←S{sub 0} transition in jet-cooled deuterated benzenes were observed using pulse dye amplification of single-mode laser light and mass-selective resonance enhanced multiphoton ionization (REMPI) detection. The vibrational and rotational structures were accurately analyzed for the vibronic levels in the S{sub 1} state. The degenerate 6{sup 1} levels of C{sub 6}H{sub 6} or C{sub 6}D{sub 6} are split into 6a{sup 1} and 6b{sup 1} in many of deuterated benzenes. The rigid-rotor rotational constants were assessed and found to be slightly different between 6a and 6b because of different mean molecular structures. Their rotational levels are significantly shifted by Coriolis interactions. It was found that the Coriolis parameter proportionally changed with the number of substituted D atoms.

  2. Initial medical management of rotator cuff tears: a demographic analysis of surgical and nonsurgical treatment in the United States Medicare population.

    PubMed

    Varkey, Dax T; Patterson, Brendan M; Creighton, R Alexander; Spang, Jeffrey T; Kamath, Ganesh V

    2016-12-01

    Rotator cuff tears have a lifetime incidence between 25% and 40% in the United States, but optimum treatment strategies and protocol have not yet been widely accepted. This study evaluated the proportions of patients treated with nonoperative and operative modalities and how this proportion has changed during an 8-year period (2005-2012) among patients with Medicare. Using the PearlDiver patient record database, we identified Medicare patients having been diagnosed with a rotator cuff tear. These patients were then stratified on the basis of treatment with physical therapy, subacromial/glenohumeral injection, or rotator cuff repair. We analyzed the data in regard to standard demographic information, comorbidities, and the Charlson Comorbidity Index. During the study period, 878,049 patients were identified and 397,116 patients had rotator cuff repair. The proportion of patients treated initially with physical therapy dropped from 30.0% in 2005 to 13.2% in 2012, and the subacromial/glenohumeral injection proportion decreased from 6.00% to 4.19% (P < .001). The proportion of patients who had rotator cuff repair increased from 33.8% to 40.4% from 2005 to 2012 (P < .001). Charlson Comorbidity Indexes were significantly lower in operative patients compared with each nonoperative treatment examined. This analysis demonstrates a significant decrease in the initial trial of nonoperative treatment and an increase in the rate of surgery. Patients undergoing rotator cuff repair had fewer comorbidities than those undergoing nonoperative treatments. It also demonstrates that patients who had a trial of injection had a higher incidence of eventual rotator cuff repair compared with the patients with an initial trial of physical therapy. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  3. Rationality, Irrationality and Escalating Behavior in Lowest Unique Bid Auctions

    PubMed Central

    Radicchi, Filippo; Baronchelli, Andrea; Amaral, Luís A. N.

    2012-01-01

    Information technology has revolutionized the traditional structure of markets. The removal of geographical and time constraints has fostered the growth of online auction markets, which now include millions of economic agents worldwide and annual transaction volumes in the billions of dollars. Here, we analyze bid histories of a little studied type of online auctions – lowest unique bid auctions. Similarly to what has been reported for foraging animals searching for scarce food, we find that agents adopt Lévy flight search strategies in their exploration of “bid space”. The Lévy regime, which is characterized by a power-law decaying probability distribution of step lengths, holds over nearly three orders of magnitude. We develop a quantitative model for lowest unique bid online auctions that reveals that agents use nearly optimal bidding strategies. However, agents participating in these auctions do not optimize their financial gain. Indeed, as long as there are many auction participants, a rational profit optimizing agent would choose not to participate in these auction markets. PMID:22279553

  4. Rationality, irrationality and escalating behavior in lowest unique bid auctions.

    PubMed

    Radicchi, Filippo; Baronchelli, Andrea; Amaral, Luís A N

    2012-01-01

    Information technology has revolutionized the traditional structure of markets. The removal of geographical and time constraints has fostered the growth of online auction markets, which now include millions of economic agents worldwide and annual transaction volumes in the billions of dollars. Here, we analyze bid histories of a little studied type of online auctions--lowest unique bid auctions. Similarly to what has been reported for foraging animals searching for scarce food, we find that agents adopt Lévy flight search strategies in their exploration of "bid space". The Lévy regime, which is characterized by a power-law decaying probability distribution of step lengths, holds over nearly three orders of magnitude. We develop a quantitative model for lowest unique bid online auctions that reveals that agents use nearly optimal bidding strategies. However, agents participating in these auctions do not optimize their financial gain. Indeed, as long as there are many auction participants, a rational profit optimizing agent would choose not to participate in these auction markets.

  5. Galaxy cluster's rotation

    NASA Astrophysics Data System (ADS)

    Manolopoulou, M.; Plionis, M.

    2017-03-01

    We study the possible rotation of cluster galaxies, developing, testing, and applying a novel algorithm which identifies rotation, if such does exist, as well as its rotational centre, its axis orientation, rotational velocity amplitude, and, finally, the clockwise or counterclockwise direction of rotation on the plane of the sky. To validate our algorithms we construct realistic Monte Carlo mock rotating clusters and confirm that our method provides robust indications of rotation. We then apply our methodology on a sample of Abell clusters with z ≲ 0.1 with member galaxies selected from the Sloan Digital Sky Survey DR10 spectroscopic data base. After excluding a number of substructured clusters, which could provide erroneous indications of rotation, and taking into account the expected fraction of misidentified coherent substructure velocities for rotation, provided by our Monte Carlo simulation analysis, we find that ∼23 per cent of our clusters are rotating under a set of strict criteria. Loosening the strictness of the criteria, on the expense of introducing spurious rotation indications, we find this fraction increasing to ∼28 per cent. We correlate our rotation indicators with the cluster dynamical state, provided either by their Bautz-Morgan type or by their X-ray isophotal shape and find for those clusters showing rotation within 1.5 h^{-1}_{70} Mpc that the significance of their rotation is related to the dynamically younger phases of cluster formation but after the initial anisotropic accretion and merging has been completed. Finally, finding rotational modes in galaxy clusters could lead to the necessity of correcting the dynamical cluster mass calculations.

  6. The S1(n, π*) states of acetaldehyde and acetone in supersonic nozzle beam: Methyl internal rotation and C=O out-of-plane wagging

    NASA Astrophysics Data System (ADS)

    Baba, Masaaki; Hanazaki, Ichiro; Nagashima, Umpei

    1985-05-01

    Fluorescence excitation spectra of CH3CHO, CH3CDO, (CH3)2CO, and (CD3)2CO have been observed in an Ar supersonic nozzle beam. Vibrational analyses have been performed for vibronic bands in the region at wavelengths longer than 313 nm. The 0-0 bands of the S1(n, π*) states were located at 29 771, 29 813, 30 435, and 30 431 cm-1, respectively. The spectra could be analyzed taking the C=O out-of-plane wagging and the CH3 internal rotation as active modes. By fitting a double minimum potential function to the observed vibrational levels, it has been shown that these molecules are pyramidally distorted in the S1(n, π*) state with barrier heights to inversion of 541, 578, 468, and 480 cm-1, respectively. Similar analyses using the Mathieu function gave threefold potential functions for the methyl internal rotation with barrier heights to rotation of 691, 645, 740, and 720 cm-1 for CH3CHO, CH3CDO, (CH3)2CO, and (CD3)2CO, respectively. High resolution measurements of rotational envelopes have shown that the out-of-plane polarization dominates in the acetone spectrum. This result, together with a detailed investigation of the vibronic intensity borrowing mechanism, has led us to conclude that the second order interaction dominates in which the methyl torsion and the C=O out-of-plane wagging are active. The origin of the methyl rotational barrier in the S1 state is discussed on the basis of our recent ab initio calculations. The hyperconjugative interaction is suggested to be important in determining the barrier.

  7. Autism or autisms? Finding the lowest common denominator.

    PubMed

    Williams, Emily L; Casanova, Manuel F

    2010-01-01

    Previous studies suggest the presence of a minicolumnopathy in autism. Minicolumnar abnormalities as well as certain migratory and proliferative defects, common to autism, may be rooted in the general mechanics of periventricular germinal cell division and maturation. Increased numbers of periventricular germinal cell/radial glia can be mimicked by a variety of different transgenic mouse models and environmental factors. These murine models and environmental factors illustrate how a fairly homogenous neuroanatomical phenotype can diverge at the genetic level. By first defining the lowest common denominator (i.e., the minicolumn) and then examining which pathways are vulnerable to involved genetic and environmental factors, we may gain a greater understanding of the pathophysiologic mechanisms underlying Autism Spectrum Conditions.

  8. Inelastic scattering of NCO([tilde X][sup 2]II) + He: Prototypical rotational state distributions for Hund's case (a) radicals

    SciTech Connect

    MacDonald, R.G.; Liu, Kopin )

    1991-11-28

    State-resolved cross sections for the inelastic scattering of the linear triatomic radical NCO([tilde X][sup 2]II[sub 3/2]) by He have been measured in a pulsed, crossed-beam apparatus at a collision energy of 3.74 kcal mol[sup [minus]1]. Dramatically different rotational state distributions were found depending on whether or not the spin-orbit state of NCO was preserved in the collision. It is proposed that the observed different distributions are generic to the inelastic scattering of a Hund's case (a) [sup 2]II radical, arising naturally as a dynamical consequence of the Renner-Teller effect.

  9. Rotational, steric, and coriolis effects on the F + HCl --> HF + Cl reaction on the 1(2)A' ground-state surface.

    PubMed

    Defazio, Paolo; Petrongolo, Carlo

    2009-04-23

    We present a quantum study of the reaction F((2)P) + HCl(X(1)Sigma(+)) --> HF(X(1)Sigma(+)) + Cl((2)P) on a recently computed 1(2)A' ground-state surface, considering HCl in the ground vibrational state, with up to 16 rotational quanta j(0). We employ the real wavepacket (WP) and flux methods for calculating coupled-channel (CC) and centrifugal-sudden (CS) initial-state probabilities up to J = 80 and 140, respectively. We also report CC and CS ground-state cross sections and CS excited-state cross sections and discuss the dynamics analyzing WP time evolutions. The HCl rotation highly enhances reaction probabilities and cross sections, as it was previously found for probabilities at J rotation to the F-H---Cl reactive vibration. WP snapshots confirm and explain the HCl rotational effects, because the density into the nearly collinear F-H---Cl product channel increases remarkably with j(0). Finally, our CS rate constant is underestimated with respect to the experiment, pointing out the need of more accurate multisurface and CC calculations.

  10. Rotational band structure in 32Mg

    NASA Astrophysics Data System (ADS)

    Crawford, H. L.; Fallon, P.; Macchiavelli, A. O.; Poves, A.; Bader, V. M.; Bazin, D.; Bowry, M.; Campbell, C. M.; Carpenter, M. P.; Clark, R. M.; Cromaz, M.; Gade, A.; Ideguchi, E.; Iwasaki, H.; Langer, C.; Lee, I. Y.; Loelius, C.; Lunderberg, E.; Morse, C.; Richard, A. L.; Rissanen, J.; Smalley, D.; Stroberg, S. R.; Weisshaar, D.; Whitmore, K.; Wiens, A.; Williams, S. J.; Wimmer, K.; Yamamato, T.

    2016-03-01

    There is significant evidence supporting the existence of deformed ground states within the neutron-rich N ≈20 neon, sodium, and magnesium isotopes that make up what is commonly called the "island of inversion." However, the rotational band structures, which are a characteristic fingerprint of a rigid nonspherical shape, have yet to be observed. In this work, we report on a measurement and analysis of the yrast (lowest lying) rotational band in 32Mg up to spin I =6+ produced in a two-step projectile fragmentation reaction and observed using the state-of-the-art γ -ray tracking detector array, GRETINA (γ -ray energy tracking in-beam nuclear array). Large-scale shell-model calculations using the SDPF-U-MIX effective interaction show excellent agreement with the new data. Moreover, a theoretical analysis of the spectrum of rotational states as a function of the pairing gap, together with cranked-shell-model calculations, provides intriguing evidence for a reduction in pairing correlations with increased angular momentum, also in line with the shell-model results.

  11. Rotational Band Structure in 32Mg

    NASA Astrophysics Data System (ADS)

    Crawford, Heather; NSCL E11029 Collaboration Team

    2016-03-01

    There is significant evidence supporting the existence of deformed ground states within the neutron-rich N =20 neon, sodium, and magnesium isotopes that make up what is commonly called the ``Island of Inversion''. However, rotational band structures, a characteristic fingerprint of a rigid non-spherical shape, have yet to be observed. We report on a measurement and analysis of the yrast (lowest lying) rotational band in 32Mg up to spin I = 6+, produced in a two-step projectile fragmentation reaction and observed using the state-of-the-art γ-ray tracking detector array, GRETINA. Large-scale shell model calculations using the SDPF-U-MIX effective interaction show excellent agreement with the new data. Moreover, a theoretical analysis of the spectrum of rotational states as a function of the pairing gap, together with cranked shell model calculations, provides intriguing evidence for a reduction in pairing correlations with increased angular momentum, also in line with the shell-model results. This material is based upon work supported by the U.S. DOE, Office of Science, NP Office under Contract No. DE-AC02-05CH11231 (LBNL). GRETINA was funded by the U.S. DOE Office of Science. Operation of the array at NSCL was supported by NSF.

  12. A new direct infrared laser absorption method for state-to-state rotational energy transfer in crossed supersonic jets: Experimental results and quantum scattering analysis for Ar+CH4

    NASA Astrophysics Data System (ADS)

    Nesbitt, David J.; Nibler, Joseph W.; Schiffman, Aram; Chapman, William B.; Hutson, Jeremy M.

    1993-06-01

    A new method for measuring state-to-state rotational energy transfer in crossed supersonic beams is described. The method is based on direct absorption of tunable, high-resolution infrared laser light by target molecules collisionally excited into final rotational states. The direct IR absorption approach offers high sensitivity, full quantum state resolution, a Doppler probe of final velocity components, and is applicable to any target molecule that absorbs in the near IR. Preliminary results are presented for Ar+CH4 scattering in crossed supersonic beams at a mean center-of-mass collision energy of 41 meV. Because of the high spectral resolution, the method can readily distinguish rotational fine structure states of A, F, and E symmetry in the tetrahedral group, as well as the much more energetically separated final j states. The results are compared with full quantum close-coupling calculations on two different Ar+CH4 potential energy surfaces. The state-to-state scattering results provide a sensitive measure of the potential anisotropy, and in particular probe the relative magnitudes of the different anisotropic terms in the potential (V3 and V4).

  13. Global Analysis of Broadband Rotation and Vibration-Rotation Spectra of Sulfur Dicyanide

    NASA Astrophysics Data System (ADS)

    Kisiel, Zbigniew; Winnewissser, Manfred; Winnewisser, Brenda P.; De Lucia, Frank C.; Tokaryk, Dennis W.; Billinghurst, Brant E.

    2013-06-01

    The successful analysis of the quantum monodromy induced features in the rotational spectrum of the NCNCS molecule prompted a quest for similar behaviour in its vibration-rotation spectrum and several high-resolution FT-IR spectra were recorded on the IFS125HR interferometer at the Canadian Light Source. The sulfur dicyanide, S(CN)_2, molecule is a precursor to NCNCS and the analysis of its spectrum proved to be a prerequisite to a search for the elusive NCNCS transitions. The CLS spectra provided the opportunity to augment the previous extensive analysis of the FASSST rotational spectrum of S(CN)_2 with vibration-rotation data, in particular from the ν_4 fundamental at 121 cm^{-1} and its related hot-band series. A global fit of the two data sets allowed retaining the detailed analysis of the previously reported perturbations in the 3ν_4 triad and 4ν_4 tetrad of states, while allowing for determination of precise energies of all low-lying vibrational states of S(CN)_2. In this way we have determined wavenumbers for five lowest fundamentals of this experimentally difficult molecule and obtained an extensive set of benchmark data for calibration of anharmonic force field calculations of such quantities as the vibration-rotation changes in rotational constants, and anharmonicity coefficients. Comparisons with results of several such calculations are presented. B.P.Winnewisser, et al., Phys. Chem. Chem. Phys. {12}, 8158 (2010). M.Winnewisser et al., 67^th OSU Symposium on Molecular Spectroscopy, The Ohio State University, Ohio 2012, TF-01. Z.Kisiel et al., J. Mol. Spectrosc. {246}, 39 (2007).

  14. Conformational state of β-hydroxynaphthylamides: Barriers for the rotation of the amide group around CN bond and dynamics of the morpholine ring.

    PubMed

    Kozlecki, Tomasz; Tolstoy, Peter M; Kwocz, Agnieszka; Vovk, Mikhail A; Kochel, Andrzej; Polowczyk, Izabela; Tretyakov, Peter Yu; Filarowski, Aleksander

    2015-10-05

    Three β-hydroxynaphthylamides (morpholine, pyrrolidine and dimethylamine derivatives) have been synthesized and their conformational state was analyzed by NMR, X-ray and DFT calculations. In aprotic solution the molecules contain intramolecular OHO hydrogen bonds, which change into intermolecular ones in solid state. The energy barriers for the amide group rotation around the CN bond were estimated from the line shape analysis of (1)H and (13)C NMR signals. A tentative correlation between the barrier height and the strength of OHO bond was proposed. Calculations of the potential energy profiles for the rotations around CC and CN bonds were done. In case of morpholine derivative experimental indications of additional dynamics: chair-chair 'ring flip' in combination with the twisting around CC bond were obtained and confirmed by quantum chemistry calculations. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Conformational state of β-hydroxynaphthylamides: Barriers for the rotation of the amide group around CN bond and dynamics of the morpholine ring

    NASA Astrophysics Data System (ADS)

    Kozlecki, Tomasz; Tolstoy, Peter M.; Kwocz, Agnieszka; Vovk, Mikhail A.; Kochel, Andrzej; Polowczyk, Izabela; Tretyakov, Peter Yu.; Filarowski, Aleksander

    2015-10-01

    Three β-hydroxynaphthylamides (morpholine, pyrrolidine and dimethylamine derivatives) have been synthesized and their conformational state was analyzed by NMR, X-ray and DFT calculations. In aprotic solution the molecules contain intramolecular OHO hydrogen bonds, which change into intermolecular ones in solid state. The energy barriers for the amide group rotation around the CN bond were estimated from the line shape analysis of 1H and 13C NMR signals. A tentative correlation between the barrier height and the strength of OHO bond was proposed. Calculations of the potential energy profiles for the rotations around CC and CN bonds were done. In case of morpholine derivative experimental indications of additional dynamics: chair-chair 'ring flip' in combination with the twisting around CC bond were obtained and confirmed by quantum chemistry calculations.

  16. The rotational spectrum of the CH radical in its a 4Sigma(-) state, studied by far-infrared laser magnetic resonance

    NASA Technical Reports Server (NTRS)

    Nelis, Thomas; Brown, John M.; Evenson, Kenneth M.

    1990-01-01

    The CH radical has been detected in its a 4Sigma(-) state by the technique of laser magnetic resonance at far-infrared wavelengths. Spectra relating to different spin components of the first three rotational transitions have been recorded. The molecule was generated either by the reaction of F atoms with CH4, with a trace of added oxygen or by the reaction of O atoms with C2H2. The observed resonances have been analyzed and fitted to determine the parameters of an effective Hamiltonian for a molecule in a 4Sigma state. The principal quantities determined are the rotational constant B0 = 451 138.434(94) MHz and the spin-spin parameter lambda(0) = 2785.83(18) MHz. Proton hyperfine parameters have also been determined.

  17. Particle-Hole Duality in the Lowest Landau Level

    NASA Astrophysics Data System (ADS)

    Nguyen, Dung Xuan; Can, Tankut; Gromov, Andrey

    2017-05-01

    We derive a number of exact relations between response functions of holomorphic, chiral fractional quantum Hall states and their particle-hole (PH) conjugates. These exact relations allow one to calculate the Hall conductivity, Hall viscosity, various Berry phases, and the static structure factor of PH conjugate states from the corresponding properties of the original states. These relations establish a precise duality between chiral quantum Hall states and their PH conjugates. The key ingredient in the proof of the relations is a generalization of Girvin's construction of PH-conjugate states to inhomogeneous magnetic field and curvature. Finally, we make several nontrivial checks of the relations, including for the Jain states and their PH conjugates.

  18. Lowest Landau level on a cone and zeta determinants

    NASA Astrophysics Data System (ADS)

    Klevtsov, Semyon

    2017-06-01

    We consider the integer QH state on Riemann surfaces with conical singularities, with the main objective of detecting the effect of the gravitational anomaly directly from the form of the wave function on a singular geometry. We suggest the formula expressing the normalisation factor of the holomorphic state in terms of the regularized zeta determinant on conical surfaces and check this relation for some model geometries. We also comment on possible extensions of this result to the fractional QH states.

  19. Correlation of Experimental and Theoretical Steady-State Spinning Motion for a Current Fighter Airplane Using Rotation-Balance Aerodynamic Data

    DTIC Science & Technology

    1978-07-01

    compared with time histories of F-4E flight test spins. Specifically, the discussion and evaluation of the application of rotation-balance data in...rate (I2) with time . The motion is suppressed to a nonoscillatory state which is not characteristic of the flight test spin. The suppression of I~A...due to thrust, aerodynamics, and inertial coupling determined from the time history are shown in Fig. 15. The oscillatory characteristic of flight

  20. Direct Oxygen Abundances for the Lowest Luminosity LVL Galaxies

    NASA Astrophysics Data System (ADS)

    Berg, Danielle; Skillman, E. D.; Marble, A. R.; van Zee, L.; Engelbracht, C. W.

    2012-01-01

    We present new MMT spectroscopic observations of HII regions in 42 of the lowest luminosity galaxies in the Spitzer Local Volume Legacy (LVL) survey. For 31 of the galaxies in our sample we were able to measure the [OIII] ? auroral line at a strength of 4σ or greater, and thus determine oxygen abundances using the direct method. Direct oxygen abundances were compared to B-band luminosity, 4.5 μm luminosity, and stellar mass to characterize the luminosity-metallicity (L-Z) and mass-metallicity (M-Z) relationships at low-luminosity. We examined a "Combined Select” sample composed of 38 objects, from the present sample and the literature, with direct oxygen abundances and reliable distance determinations (based on the tip of the red giant branch or Cepheid variables). The B-band and 4.5 μm L-Z relationships were found to be 12+log(O/H) = (6.19±0.07) + (-0.12±0.01)MB and 12+log(O/H) = (5.93±0.11) + (-0.11±0.01)M[4.5] with dispersions of σ = 0.17 and σ = 0.14 respectively. Since the slope of the L-Z relationship doesn't seem to vary from the optical to the near-IR, as has been observed in studies of more luminous galaxies, we propose that less extinction due to dust is created in the lowest luminosity galaxies. We subsequently derived a M-Z relationship of 12+log(O/H) = (5.49±0.23) + (0.31±0.03)log M*, with a dispersion of σ = 0.16. None of the relationships seem to hold an advantage with respect to dispersion, supporting the idea of minimized dust. Additionally, the trend of N/O abundance with respect to B-V color and oxygen abundance was examined. Similar to the conclusions of van Zee & Haynes (2006), we find a positive correlation between N/O ratio and B-V color: log(N/O) = 0.92 (B-V) - 1.83. Furthermore, there are no objects with high N/O ratio below 12+log(O/H)=7.9.

  1. Rotational structure in the near-infrared absorption spectrum of ozone

    NASA Technical Reports Server (NTRS)

    Anderson, Stuart M.; Hupalo, Peter; Mauersberger, Konrad

    1993-01-01

    The lowest energy members of the near-IR absorption bands of ozone possess fine structure which is probably due to the rotation of the molecule in the upper vibronic state, suggesting that this state is metastable. A preliminary analysis of the structures as rotational subbands supports a recent theoretical assignment of the near-IR vibronic features to the 3A2 - 1A1 electronic transition. A binding energy of about 0.1 eV is inferred from the breakoff in the observed structure.

  2. Rotational structure in the near-infrared absorption spectrum of ozone

    NASA Technical Reports Server (NTRS)

    Anderson, Stuart M.; Hupalo, Peter; Mauersberger, Konrad

    1993-01-01

    The lowest energy members of the near-IR absorption bands of ozone possess fine structure which is probably due to the rotation of the molecule in the upper vibronic state, suggesting that this state is metastable. A preliminary analysis of the structures as rotational subbands supports a recent theoretical assignment of the near-IR vibronic features to the 3A2 - 1A1 electronic transition. A binding energy of about 0.1 eV is inferred from the breakoff in the observed structure.

  3. Rotational branching ratios and photoelectron angular distributions in resonance enhanced multiphoton ionization of HBr via the F sup 1. Delta. sub 2 Rydberg state

    SciTech Connect

    Wang, K.; McKoy, V. )

    1991-12-01

    Results of theoretical studies of rotational ion distributions in the {ital X} {sup 2}{Pi}{sub 1/2} ground state of HBr{sup +} resulting from (2+1) resonance enhanced multiphoton ionization (REMPI) via the {ital S}(2) branch of the {ital F} {sup 1}{Delta}{sub 2} Rydberg state are reported. These results show a strongly parity-favored ion distribution with about 80% population in the ({minus}) component of the {Lambda} doublet of {ital J}{sup +} rotational levels. The 20% population in the other parity component of the {Lambda} doublet can be seen to be due to odd partial wave contributions to the photoelectron matrix elements which arise primarily from non-atomic-like behavior of the electronic continuum. This, in turn, is due to angular momentum coupling in the photoelectron orbital brought about by the torques of the nonspherical molecular ion potential. We demonstrate that the effect of alignment on these ion distributions, although not large, is important. Photoelectron angular distributions and alignment of the {ital J} levels of the HBr{sup +} ions are also presented. Rotational branching ratios and photoelectron angular distributions resulting from (2+1{prime}) REMPI of HBr via several {ital S} branches of the {ital F} {sup 1}{Delta}{sub 2} state are also shown for near-threshold photoelectron energies.

  4. Rotational moulding.

    PubMed

    Crawford, R J; Kearns, M P

    2003-10-01

    Rotational moulding promises designers attractive economics and a low-pressure process. The benefits of rotational moulding are compared here with other manufacturing methods such as injection and blow moulding.

  5. Rotating Vesta

    NASA Image and Video Library

    Astronomers combined 146 exposures taken by NASA's Hubble SpaceTelescope to make this 73-frame movie of the asteroid Vesta's rotation.Vesta completes a rotation every 5.34 hours.› Asteroid and...

  6. Torsion-rotation-vibration effects in the ground and first excited states of methacrolein, a major atmospheric oxidation product of isoprene

    SciTech Connect

    Zakharenko, O.; Motiyenko, R. A.; Aviles Moreno, J.-R.; Huet, T. R.; Jabri, A.; Kleiner, I.

    2016-01-14

    Methacrolein is a major oxidation product of isoprene emitted in the troposphere. New spectroscopy information is provided with the aim to allow unambiguous identification of this complex molecule, characterized by a large amplitude motion associated with the methyl top. State-of-the-art millimeter-wave spectroscopy experiments coupled to quantum chemical calculations have been performed. For the most stable s-trans conformer of atmospheric interest, the torsional and rotational structures have been characterized for the ground state, the first excited methyl torsional state (ν{sub 27}), and the first excited skeletal torsional state (ν{sub 26}). The inverse sequence of A and E tunneling sub-states as well as anomalous A-E splittings observed for the rotational lines of v{sub 26} = 1 state clearly indicates a coupling between methyl torsion and skeletal torsion. A comprehensive set of molecular parameters has been obtained. The far infrared spectrum of Durig et al. [Spectrochim. Acta, Part A 42, 89–103 (1986)] was reproduced, and a Fermi interaction between ν{sub 25} and 2ν{sub 27} was evidenced.

  7. Torsion-rotation-vibration effects in the ground and first excited states of methacrolein, a major atmospheric oxidation product of isoprene

    NASA Astrophysics Data System (ADS)

    Zakharenko, O.; Motiyenko, R. A.; Aviles Moreno, J.-R.; Jabri, A.; Kleiner, I.; Huet, T. R.

    2016-01-01

    Methacrolein is a major oxidation product of isoprene emitted in the troposphere. New spectroscopy information is provided with the aim to allow unambiguous identification of this complex molecule, characterized by a large amplitude motion associated with the methyl top. State-of-the-art millimeter-wave spectroscopy experiments coupled to quantum chemical calculations have been performed. For the most stable s-trans conformer of atmospheric interest, the torsional and rotational structures have been characterized for the ground state, the first excited methyl torsional state (ν27), and the first excited skeletal torsional state (ν26). The inverse sequence of A and E tunneling sub-states as well as anomalous A-E splittings observed for the rotational lines of v26 = 1 state clearly indicates a coupling between methyl torsion and skeletal torsion. A comprehensive set of molecular parameters has been obtained. The far infrared spectrum of Durig et al. [Spectrochim. Acta, Part A 42, 89-103 (1986)] was reproduced, and a Fermi interaction between ν25 and 2ν27 was evidenced.

  8. The Complete Molecular Geometry of Salicyl Aldehyde from Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dorosh, O.; Bialkowska-Jaworska, E.; Kisiel, Z.; Pszczolkowski, L.; Kanska, M.; Krygowski, T. M.; Maeder, H.

    2013-06-01

    Salicyl aldehyde is a well known planar molecule containing an internal hydrogen bond. In preparing the publication of our previous report of the study of its rotational spectrum we have taken the opportunity to update the structure determination of this molecule to the complete r_e^{SE} geometry. The molecule contains 15 atoms and we have used supersonic expansion FTMW spectroscopy to obtain rotational constants for a total 26 different isotopic species, including all singly substitued species relative to the parent molecule. The ^{13}C and ^{18}O substitutions were measured in natural abundance, while deuterium substitutions were carried out synthetically. The r_e^{SE} determination requires the calculation of vibration-rotation changes in rotational constants from an ab initio anharmonic force field, which necessitates some compromises in the level of calculation for a molecule of the size of salicyl aldehyde. For this reason we studied the five lowest vibrationally excited states, by using the combination of room-temperature mm-wave spectroscopy and waveguide Fourier transform cm-wave spectroscopy. The experimental excited state rotational constants were then used to calibrate the anharmonic force field calculation. The resulting r_e^{SE} geometry is compared with other types of geometry determination possible from this data, with emphasis on the effect of the near zero principal coordinate of the important C_2 atom. Z.Kisiel et al., 61^{st} OSU Symposium on Molecular Spectroscopy, The Ohio State University, Ohio 2006, RI-12.

  9. Three-dimensional Spherical Simulations of Solar Convection. I. Differential Rotation and Pattern Evolution Achieved with Laminar and Turbulent States

    NASA Astrophysics Data System (ADS)

    Miesch, Mark S.; Elliott, Julian R.; Toomre, Juri; Clune, Tom L.; Glatzmaier, Gary A.; Gilman, Peter A.

    2000-03-01

    Rotationally constrained convection possesses velocity correlations that transport momentum and drive mean flows such as differential rotation. The nature of this transport can be very complex in turbulent flow regimes, where large-scale, coherent vorticity structures and mean flows can be established by smaller scale turbulence through inverse cascades. The dynamics of the highly turbulent solar convection zone therefore may be quite different than in early global-scale numerical models, which were limited by computational resources to nearly laminar flows. Recent progress in high-performance computing technology and ongoing helioseismic investigations of the dynamics of the solar interior have motivated us to develop more sophisticated numerical models of global-scale solar convection. Here we report three-dimensional simulations of compressible, penetrative convection in rotating spherical shells in both laminar and turbulent parameter regimes. The convective structure in the laminar case is dominated by ``banana cells,'' but the turbulent case is much more complex, with an intricate, rapidly evolving downflow network in the upper convection zone and an intermittent, plume-dominated structure in the lower convection zone and overshoot region. Convective patterns generally propagate prograde at low latitudes and retrograde at high latitudes relative to the local rotation. The differential rotation profiles show some similarity with helioseismic determinations of the solar rotation but still exhibit significantly more cylindrical alignment. Strong, intermittent, vortical downflow lanes and plumes play an important dynamical role in turbulent flow regimes and are responsible for significant differences relative to laminar flows with regard to momentum and energy transport and to the structure of the overshoot region at the base of the convection zone.

  10. Fuzzy logic control of rotating drum bioreactor for improved production of amylase and protease enzymes by Aspergillus oryzae in solid-state fermentation.

    PubMed

    Sukumprasertsri, Monton; Unrean, Pornkamol; Pimsamarn, Jindarat; Kitsubun, Panit; Tongta, Anan

    2013-03-01

    In this study, we compared the performance of two control systems, fuzzy logic control (FLC) and conventional control (CC). The control systems were applied for controlling temperature and substrate moisture content in a solidstate fermentation for the biosynthesis of amylase and protease enzymes by Aspergillus oryzae. The fermentation process was achieved in a 200 L rotating drum bioreactor. Three factors affecting temperature and moisture content in the solid-state fermentation were considered. They were inlet air velocity, speed of the rotating drum bioreactor, and spray water addition. The fuzzy logic control system was designed using four input variables: air velocity, substrate temperature, fermentation time, and rotation speed. The temperature was controlled by two variables, inlet air velocity and rotational speed of bioreactor, while the moisture content was controlled by spray water. Experimental results confirmed that the FLC system could effectively control the temperature and moisture content of substrate better than the CC system, resulting in an increased enzyme production by A. oryzae. Thus, the fuzzy logic control is a promising control system that can be applied for enhanced production of enzymes in solidstate fermentation.

  11. Spin-Spin and Spin-Rotation Fine Structure of the Metastable a ^3Σ_u^+ States of Molecular Helium

    NASA Astrophysics Data System (ADS)

    Jansen, Paul; Semeria, Luca; Merkt, Frederic

    2017-06-01

    In a recent series of experiments, we have determined term values of all rotational levels of the X^+ ^2Σ_u^+ (ν^+=0) ground vibronic state of ^4He_2^+ with rotational quantum number N^+≤ 19 at an accuracy of 25 MHz using MQDT-assisted Rydberg-series extrapolation of metastable helium molecules in the a ^3Σ_u^+ state. The precison of these experiments was limited by the 150 MHz linewidth of the pulsed laser system employed. In order to improve our resolution and possibly observe the spin-rotation splitting in the He_2^+ ion, we have replaced the pulsed laser by a CW laser system with a bandwidth of 1.5 MHz. This system was used to measure the spin-spin and spin-rotation fine structure of metastable He_2 in the a ^3Σ_u^+ (ν''=0) state. Metastable helium molecules were produced by striking a discharge in an expansion of neat helium gas. By cooling the source to a temperature of 10 K, the velocity of the molecular beam was reduced to 500 m/s and an experimental Doppler-limited linewidth of 25 MHz was observed. Fine-structure splittings for all rotational levels with N''≤ 27 have been measured at an accuracy of 5 MHz and, when possible, have been compared to the values reported in earlier investigations. This comparison revealed a discrepancy that increased with increasing values of N''. To verify our results, we have recently constructed a variaton of a classical molecular-beam magnetic-resonance setup that uses a multistage Zeeman decelerator and a RF stripline for de- and repopulation of the F_2 spin-rotational components with J''=N'', respectively. P. Jansen, L. Semeria, L. Esteban Hofer, S. Scheidegger, J. A. Agner, H. Schmutz, and F. Merkt, Phys. Rev. Lett. 114, 133202 (2015). L. Semeria, P. Jansen, and F. Merkt, J. Chem. Phys. 145, 204301 (2016). W. Lichten, M. V. McCusker, and T. L. Vierima, J. Chem. Phys. 61, 2200 (1974). W. Lichten and T. Wik, J. Chem. Phys. 69, 98 (1978). M. Kristensen and N. Bjerre, J. Chem. Phys. 93, 983 (1990). I Hazell, A

  12. Evidence for distributed clockwise rotation of the crust in the northwestern United States from fault geometries and focal mechanisms

    NASA Astrophysics Data System (ADS)

    Brocher, Thomas M.; Wells, Ray E.; Lamb, Andrew P.; Weaver, Craig S.

    2017-05-01

    Paleomagnetic and GPS data indicate that Washington and Oregon have rotated clockwise for the past 16 Myr. Late Cenozoic and Quaternary fault geometries, seismicity lineaments, and focal mechanisms provide evidence that this rotation is accommodated by north directed thrusting and right-lateral strike-slip faulting in Washington, and SW to W directed normal faulting and right-lateral strike-slip faulting to the east. Several curvilinear NW to NNW trending high-angle strike-slip faults and seismicity lineaments in Washington and NW Oregon define a geologic pole (117.7°W, 47.9°N) of rotation relative to North America. Many faults and focal mechanisms throughout northwestern U.S. and southwestern British Columbia have orientations consistent with this geologic pole as do GPS surface velocities corrected for elastic Cascadia subduction zone coupling. Large Quaternary normal faults radial to the geologic pole, which appear to accommodate crustal rotation via crustal extension, are widespread and can be found along the Lewis and Clark zone in Montana, within the Centennial fault system north of the Snake River Plain in Idaho and Montana, to the west of the Wasatch Front in Utah, and within the northern Basin and Range in Oregon and Nevada. Distributed strike-slip faults are most prominent in western Washington and Oregon and may serve to transfer slip between faults throughout the northwestern U.S.

  13. Evidence for distributed clockwise rotation of the crust in the northwestern United States from fault geometries and focal mechanisms

    USGS Publications Warehouse

    Brocher, Thomas M.; Wells, Ray E.; Lamb, Andrew P.; Weaver, Craig S.

    2017-01-01

    Paleomagnetic and GPS data indicate that Washington and Oregon have rotated clockwise for the past 16 Myr. Late Cenozoic and Quaternary fault geometries, seismicity lineaments, and focal mechanisms provide evidence that this rotation is accommodated by north directed thrusting and right-lateral strike-slip faulting in Washington, and SW to W directed normal faulting and right-lateral strike-slip faulting to the east. Several curvilinear NW to NNW trending high-angle strike-slip faults and seismicity lineaments in Washington and NW Oregon define a geologic pole (117.7°W, 47.9°N) of rotation relative to North America. Many faults and focal mechanisms throughout northwestern U.S. and southwestern British Columbia have orientations consistent with this geologic pole as do GPS surface velocities corrected for elastic Cascadia subduction zone coupling. Large Quaternary normal faults radial to the geologic pole, which appear to accommodate crustal rotation via crustal extension, are widespread and can be found along the Lewis and Clark zone in Montana, within the Centennial fault system north of the Snake River Plain in Idaho and Montana, to the west of the Wasatch Front in Utah, and within the northern Basin and Range in Oregon and Nevada. Distributed strike-slip faults are most prominent in western Washington and Oregon and may serve to transfer slip between faults throughout the northwestern U.S.

  14. Crystal structure of release factor RF3 trapped in the GTP state on a rotated conformation of the ribosome

    SciTech Connect

    Zhou, Jie; Lancaster, Laura; Trakhanov, Sergei; Noller, Harry F.

    2012-03-26

    The class II release factor RF3 is a GTPase related to elongation factor EF-G, which catalyzes release of class I release factors RF1 and RF2 from the ribosome after termination of protein synthesis. The 3.3 {angstrom} crystal structure of the RF3 {center_dot} GDPNP {center_dot} ribosome complex provides a high-resolution description of interactions and structural rearrangements that occur when binding of this translational GTPase induces large-scale rotational movements in the ribosome. RF3 induces a 7{sup o} rotation of the body and 14{sup o} rotation of the head of the 30S ribosomal subunit, and itself undergoes inter- and intradomain conformational rearrangements. We suggest that ordering of critical elements of switch loop I and the P loop, which help to form the GTPase catalytic site, are caused by interactions between the G domain of RF3 and the sarcin-ricin loop of 23S rRNA. The rotational movements in the ribosome induced by RF3, and its distinctly different binding orientation to the sarcin-ricin loop of 23S rRNA, raise interesting implications for the mechanism of action of EF-G in translocation.

  15. Production of cold beams of ND{sub 3} with variable rotational state distributions by electrostatic extraction of He and Ne buffer-gas-cooled beams

    SciTech Connect

    Twyman, Kathryn S.; Bell, Martin T.; Heazlewood, Brianna R.; Softley, Timothy P.

    2014-07-14

    The measurement of the rotational state distribution of a velocity-selected, buffer-gas-cooled beam of ND{sub 3} is described. In an apparatus recently constructed to study cold ion-molecule collisions, the ND{sub 3} beam is extracted from a cryogenically cooled buffer-gas cell using a 2.15 m long electrostatic quadrupole guide with three 90° bends. (2+1) resonance enhanced multiphoton ionization spectra of molecules exiting the guide show that beams of ND{sub 3} can be produced with rotational state populations corresponding to approximately T{sub rot} = 9–18 K, achieved through manipulation of the temperature of the buffer-gas cell (operated at 6 K or 17 K), the identity of the buffer gas (He or Ne), or the relative densities of the buffer gas and ND{sub 3}. The translational temperature of the guided ND{sub 3} is found to be similar in a 6 K helium and 17 K neon buffer-gas cell (peak kinetic energies of 6.92(0.13) K and 5.90(0.01) K, respectively). The characterization of this cold-molecule source provides an opportunity for the first experimental investigations into the rotational dependence of reaction cross sections in low temperature collisions.

  16. Observation of b2 symmetry vibrational levels of the SO2C 1B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants

    DOE PAGES

    Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; ...

    2016-04-14

    Here, the C 1B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X~ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C state below 1600 cm–1 of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, itmore » allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry, and to determine accurately the vibrational dependence of the rotational constants in the distorted C electronic state.« less

  17. (p,q) deformations and (p,q)-vector coherent states of the Jaynes-Cummings model in the rotating wave approximation

    SciTech Connect

    Ben Geloun, Joseph; Govaerts, Jan; Hounkonnou, M. Norbert

    2007-03-15

    Classes of (p,q) deformations of the Jaynes-Cummings model in the rotating wave approximation are considered. Diagonalization of the Hamiltonian is performed exactly, leading to useful spectral decompositions of a series of relevant operators. The latter include ladder operators acting between adjacent energy eigenstates within two separate infinite discrete towers, except for a singleton state. These ladder operators allow for the construction of (p,q)-deformed vector coherent states. Using (p,q) arithmetics, explicit and exact solutions to the associated moment problem are displayed, providing new classes of coherent states for such models. Finally, in the limit of decoupled spin sectors, our analysis translates into (p,q) deformations of the supersymmetric harmonic oscillator, such that the two supersymmetric sectors get intertwined through the action of the ladder operators as well as in the associated coherent states.

  18. Observation of b2 symmetry vibrational levels of the SO2 C̃ (1)B2 state: Vibrational level staggering, Coriolis interactions, and rotation-vibration constants.

    PubMed

    Park, G Barratt; Jiang, Jun; Saladrigas, Catherine A; Field, Robert W

    2016-04-14

    The C̃ (1)B2 state of SO2 has a double-minimum potential in the antisymmetric stretch coordinate, such that the minimum energy geometry has nonequivalent SO bond lengths. However, low-lying levels with odd quanta of antisymmetric stretch (b2 vibrational symmetry) have not previously been observed because transitions into these levels from the zero-point level of the X̃ state are vibronically forbidden. We use IR-UV double resonance to observe the b2 vibrational levels of the C̃ state below 1600 cm(-1) of vibrational excitation. This enables a direct characterization of the vibrational level staggering that results from the double-minimum potential. In addition, it allows us to deperturb the strong c-axis Coriolis interactions between levels of a1 and b2 vibrational symmetry and to determine accurately the vibrational dependence of the rotational constants in the distorted C̃ electronic state.

  19. Rotational testing.

    PubMed

    Furman, J M

    2016-01-01

    The natural stimulus for the semicircular canals is rotation of the head, which also might stimulate the otolith organs. Vestibular stimulation usually induces eye movements via the vestibulo-ocular reflex (VOR). The orientation of the subject with respect to the axis of rotation and the orientation of the axis of rotation with respect to gravity together determine which labyrinthine receptors are stimulated for particular motion trajectories. Rotational testing usually includes the measurement of eye movements via a video system but might use a subject's perception of motion. The most common types of rotational testing are whole-body computer-controlled sinusoidal or trapezoidal stimuli during earth-vertical axis rotation (EVAR), which stimulates primarily the horizontal semicircular canals bilaterally. Recently, manual impulsive rotations, known as head impulse testing (HIT), have been developed to assess individual horizontal semicircular canals. Most types of rotational stimuli are not used routinely in the clinical setting but may be used in selected research environments. This chapter will discuss clinically relevant rotational stimuli and several types of rotational testing that are used primarily in research settings.

  20. Efficient entanglement concentration of arbitrary unknown less-entangled three-atom W states via photonic Faraday rotation in cavity QED

    NASA Astrophysics Data System (ADS)

    Cao, Cong; Fan, Ling; Chen, Xi; Duan, Yu-Wen; Wang, Tie-Jun; Zhang, Ru; Wang, Chuan

    2017-04-01

    We propose an efficient entanglement concentration protocol (ECP) for nonlocal three-atom systems in an arbitrary unknown less-entangled W state, resorting to the Faraday rotation of photonic polarization in cavity quantum electrodynamics and the systematic concentration method. In the first step of the present ECP, one party in quantum communication performs a parity-check measurement on her two atoms in two three-atom systems for dividing the composite six-atom systems into two groups. In the first group, the three parties will obtain some three-atom systems in a less-entangled state with two unknown coefficients. In the second group, they will obtain some less-entangled two-atom systems. In the second step of the ECP, the three parties can obtain a subset of three-atom systems in the standard maximally entangled W state by exploiting the above three-atom and two-atom systems. Moreover, the preserved systems in the failed instances can be used as the resource for the entanglement concentration in the next round. The total success probability of the ECP can therefore be largely increased by iterating the entanglement concentration process several rounds. The distinct feature of our ECP is that we can concentrate arbitrary unknown atomic entangled W states via photonic Faraday rotation, and thus it may be universal and useful for entanglement concentration in future quantum communication network.

  1. Effects of rotation on the sleep state-dependent midlatency auditory evoked P50 potential in the human

    NASA Technical Reports Server (NTRS)

    Dornhoffer, John L.; Mamiya, N.; Bray, P.; Skinner, Robert D.; Garcia-Rill, Edgar

    2002-01-01

    Sopite syndrome, characterized by loss of initiative, sensitivity to normally innocuous sensory stimuli, and impaired concentration amounting to a sensory gating deficit, is commonly associated with Space Motion Sickness (SMS). The amplitude of the P50 potential is a measure of level of arousal, and a paired-stimulus paradigm can be used to measure sensory gating. We used the rotary chair to elicit the sensory mismatch that occurs with SMS by overstimulating the vestibular apparatus. The effects of rotation on the manifestation of the P50 midlatency auditory evoked response were then assessed as a measure of arousal and distractibility. Results showed that rotation-induced motion sickness produced no change in the level of arousal but did produce a significant deficit in sensory gating, indicating that some of the attentional and cognitive deficits observed with SMS may be due to distractibility induced by decreased habituation to repetitive stimuli.

  2. Accurate rotational constant and bond lengths of hexafluorobenzene by femtosecond rotational Raman coherence spectroscopy and ab initio calculations.

    PubMed

    Den, Takuya S; Frey, Hans-Martin; Leutwyler, Samuel

    2014-11-21

    The gas-phase rotational motion of hexafluorobenzene has been measured in real time using femtosecond (fs) time-resolved rotational Raman coherence spectroscopy (RR-RCS) at T = 100 and 295 K. This four-wave mixing method allows to probe the rotation of non-polar gas-phase molecules with fs time resolution over times up to ∼5 ns. The ground state rotational constant of hexafluorobenzene is determined as B0 = 1029.740(28) MHz (2σ uncertainty) from RR-RCS transients measured in a pulsed seeded supersonic jet, where essentially only the v = 0 state is populated. Using this B0 value, RR-RCS measurements in a room temperature gas cell give the rotational constants Bv of the five lowest-lying thermally populated vibrationally excited states ν7/8, ν9, ν11/12, ν13, and ν14/15. Their Bv constants differ from B0 by between -1.02 MHz and +2.23 MHz. Combining the B0 with the results of all-electron coupled-cluster CCSD(T) calculations of Demaison et al. [Mol. Phys. 111, 1539 (2013)] and of our own allow to determine the C-C and C-F semi-experimental equilibrium bond lengths re(C-C) = 1.3866(3) Å and re(C-F) = 1.3244(4) Å. These agree with the CCSD(T)/wCVQZ re bond lengths calculated by Demaison et al. within ±0.0005 Å. We also calculate the semi-experimental thermally averaged bond lengths rg(C-C)=1.3907(3) Å and rg(C-F)=1.3250(4) Å. These are at least ten times more accurate than two sets of experimental gas-phase electron diffraction rg bond lengths measured in the 1960s.

  3. Transition from an unstable synchronization state with transient oscillation cessations to spiral rotation in a coupled chemical oscillator system

    NASA Astrophysics Data System (ADS)

    Nishiyama, Nobuaki; Matsuyama, Tomoko

    1997-02-01

    Spatiotemporal patterns of chemical wave propagation in the assemblies of nine cation-exchange beads loaded with the catalyst ferroin of Belousov-Zhabotinsky reaction are reported. The beads are immersed in the reaction mixture, on which periodic chemical waves are emerged. In the bead assemblies, abrupt changes of initiation site and direction of the periodic chemical waves were observed. In some cases, it was observed that transient oscillation cessations and the following rotating spiral wave occur.

  4. Fill-level symmetry and minimization of energy states in rotating tumblers with polygonal cross-sections

    NASA Astrophysics Data System (ADS)

    Pohlman, Nicholas A.; Paprocki, Daniel F., Jr.; Si, Yun

    2012-11-01

    Typically in rotating tumblers, constant rotation rates and circular cross-sections are used as they jointly produce a steady, uniform flowing layer at the free surface. On the other hand, experiments conducted in polygon-shaped tumblers produce unsteady conditions due to the rapidly changing flowing layer length. Results analyzing free surface properties indicate that the particle dynamics within the flowing layer attempt to minimize energy of the flowing system: The arithmetic difference between the angle of repose and the tumbler orientation has a functional relationship with the instantaneous flowing layer length in the form of a catenary. The peaks of the catenary are affected by the number of sides on the polygon cross-section as well as the symmetry around the critical 50% fill fraction. Furthermore, oscillation of the flowing layer position appears to affect the free surface curvature. This result is likely due to the rapidly increasing and decreasing length of the free surface and the rotational inertia of particles entering the flowing layer. Funding provided by NIU's Office of Student Engagement and Experiential Learning.

  5. Approximate Theoretical Model for the Five Electronic States (Ω = 5/2, 3/2, 3/2, 1/2, 1/2) Arising from the Ground 3d9 Configuration in Nickel Halide Molecules and for Rotational Levels of the Two Ω = 1/2 States in that Manifold

    NASA Astrophysics Data System (ADS)

    Cheung, Allan S.-C.

    2011-06-01

    An effective Hamiltonian for a non-rotating diatomic molecule containing only crystal-field and spin-orbit operators has been set up to describe the energies of the five spin-orbit components that arise in the ground electronic configuration of the nickel monohalides. The model assumes that bonding in the nickel halides has the approximate form Ni+X-, with an electronic 3d9 configuration plus closed shells on the Ni+ moiety and a closed shell configuration on the X&- moiety. Least-squares fits of the observed five spin-orbit components of the three lowest electronic states in NiF and NiCl are then carried out in terms of the three crystal field parameters C0, C2, C4 and the spin-orbit coupling constant A. Following this, the usual effective Hamiltonian B(J-L-S)^2 for a rotating diatomic molecule is used to derive expressions for the unusually large Ω-type doubling parameter p in the two Ω = 1/2 states in the 3d9 manifold. These expressions show (for certain sign conventions) that the sum of the two p values should be -2B, but that their difference can vary between -10B and +10B. The theoretical magnitudes for p are in good agreement with the two observed p values for both NiF and NiCl, but the signs are not. The experimental signs can be brought into agreement with the theoretical signs by a fairly massive change in +/- parity assignments in the NiF and NiCl literature. The last part of the talk will focus on the theoretical and experimental implications of these parity changes.

  6. Improved calculations of the lowest vibrational transitions in HeH{sup +}

    SciTech Connect

    Bubin, Sergiy; Stanke, Monika; Kedziera, Dariusz; Adamowicz, Ludwik

    2007-08-15

    More accurate variational calculations of the lowest three pure vibrational states (v=0,1,2) of the {sup 4}HeH{sup +} molecular ion have been carried out without assuming the Born-Oppenheimer approximation. In the calculations we included the complete set of {alpha}{sup 2} relativistic corrections, i.e., mass-velocity, Darwin, spin-spin, and orbit-orbit. This allowed us to improve the agreement between the theory and the experiment for the vibrational frequencies of the 1{yields}0 and 2{yields}1 transitions as compared to our previous calculations [Stanke et al., Phys. Rev. Lett. 96, 233002 (2006)].

  7. Sigma meson and lowest possible glueball candidate in an extended linear {sigma} model

    SciTech Connect

    Mukherjee, Tamal K.; Huang Mei; Yan Qishu

    2012-10-23

    We formulate an extended linear {sigma} model of a quarkonia nonet and a tetraquark nonet as well as a complex iso-singlet (glueball) field to study the low-lying scalar meson. Chiral symmetry and U{sub A}(1) symmetry and their breaking play important role to shape the scalar meson spectrum in our work. Based on our study we will comment on what may be the mass of the lowest possible scalar and pseudoscalar glueball states. We will also discuss on what may be the nature of the sigma or f{sub 0}(600) meson.

  8. Fine structure of the lowest Landau level in suspended trilayer graphene

    NASA Astrophysics Data System (ADS)

    van Elferen, H. J.; Veligura, A.; Tombros, N.; Kurganova, E. V.; van Wees, B. J.; Maan, J. C.; Zeitler, U.

    2013-09-01

    Magnetotransport experiments on ABC-stacked suspended trilayer graphene reveal a complete splitting of the 12-fold degenerated lowest Landau level, and, in particular, the opening of an exchange-driven gap at the charge neutrality point. A quantitative analysis of distinctness of the quantum Hall plateaus as a function of field yields a hierarchy of the filling factors: ν=6, 4, and 0 are the most pronounced, followed by ν=3, and finally ν=1, 2, and 5. Apart from the appearance of a ν=4 state, which is probably caused by a layer asymmetry, this sequence is in agreement with Hund's rules for ABC-stacked trilayer graphene.

  9. Rotational spectra of methyl ethyl and methyl propyl nitrosamines. Conformational assignment, internal rotation and quadrupole coupling

    NASA Astrophysics Data System (ADS)

    Walker, A. R. Hight; Lou, Qi; Bohn, Robert K.; Novick, Stewart E.

    1995-02-01

    A structural determination of two carcinogenic nitrosamines, methyl ethyl and methyl propyl nitrosamine, was performed. Microwave spectra were gathered from both a Stark cell spectrometer and a pulsed jet Fabry-Perot Fourier transform microwave spectrometer. Each rotational transition is split into quadrupole hyperfine components by two nitrogen nuclei. This quadrupole pattern is doubled by a low barrier methyl rotor which produces resolvable A and E states. Rotational spectra were assigned for one conformer of methyl ethyl nitrosamine and two conformers of methyl propyl nitrosamine. The lowest energy conformers of each compound, according to empirical force field calculations, were assigned. The structure found for methyl ethyl nitrosamine has the nitrosyl oxygen on the methyl side with the terminal methyl group of the ethyl chain in the gauche position (OMG). Both conformers of methyl propyl nitrosamine have the same skeletal structure as the methyl ethyl compound; one conformer has the terminal methyl of the propyl group in the anti position (OMGA) while the other conformer has this methyl in the gauche position (OMGG -). Rotational constants and quadrupole coupling constants are reported for each assigned species. A barrier to internal rotation of the N-methyl group in each compound is also reported.

  10. Nuclear-spin optical rotation in xenon

    NASA Astrophysics Data System (ADS)

    Savukov, I.

    2015-10-01

    The nuclear-spin optical rotation (NSOR) effect, which has potential applications in correlated nuclear-spin-resonance optical spectroscopy, has previously been explored experimentally and theoretically in liquid Xe. Calculations of the Xe NSOR constant are very challenging because the result is sensitive to correlations, relativistic effects, and the choice of basis, with strong cancellation between contributions from lowest and remaining states. The relativistic configuration-interaction many-body-theory approach, presented here, is promising because this approach has been successful in predicting various properties of noble-gas atoms, such as energies, oscillator strengths (OSs), Verdet constants, and photoionization cross sections. However, correlations become stronger along the sequence of noble-gas atoms and the theoretical accuracy in Xe is not as high as, for example, in neon and argon. To improve the accuracy of the Xe Verdet and NSOR constants, which are calculated as explicit sums over the excited states, theoretical values for the several lowest levels are replaced with empirical values of energies, OSs, and hyperfine structure constants. We found that the Xe Verdet constant is in excellent agreement with accurate measurements. To take into account liquid effects, empirical data for energy shifts were also used to correct the NSOR constant. The resulting Xe NSOR constant is in a good agreement with experiment, although the liquid-state effect is treated quite approximately.

  11. Steady-state temperature distribution within a Brayton rotating unit operating in a power conversion system using helium-xenon gas

    NASA Technical Reports Server (NTRS)

    Johnsen, R. L.; Namkoong, D.; Edkin, R. A.

    1971-01-01

    The Brayton rotating unit (BRU), consisting of a turbine, an alternator, and a compressor, was tested as part of a Brayton cycle power conversion system over a side range of steady state operating conditions. The working fluid in the system was a mixture of helium-xenon gases. Turbine inlet temperature was varied from 1200 to 1600 F, compressor inlet temperature from 60 to 120 F, compressor discharge pressure from 20 to 45 psia, rotative speed from 32 400 to 39 600 rpm, and alternator liquid-coolant flow rate from 0.01 to 0.27 pound per second. Test results indicated that the BRU internal temperatures were highly sensitive to alternator coolant flow below the design value of 0.12 pound per second but much less so at higher values. The armature winding temperature was not influenced significantly by turbine inlet temperature, but was sensitive, up to 20 F per kVA alternator output, to varying alternator output. When only the rotational speed was changed (+ or - 10% of rated value), the BRU internal temperatures varied directly with the speed.

  12. Rotationally resolved S1<-- S0 electronic spectra of fluorene, carbazole, and dibenzofuran: evidence for Herzberg-Teller coupling with the S2 state.

    PubMed

    Yi, John T; Alvarez-Valtierra, Leonardo; Pratt, David W

    2006-06-28

    Rotationally resolved fluorescence excitation spectra of the S1 <-- S0 origin bands and higher vibronic bands of fluorene (FLU), carbazole (CAR), and dibenzofuran (DBF) have been observed and assigned. Analyses of these data show that replacement of the CH2 group in FLU with a NH group in CAR and an O atom in DBF produces only localized changes in structure, in the ground state. But the three molecules exhibit different changes in geometry when they are excited by light. The S1 states of the three molecules also are electronically very different. The S1 <-- S0 transition moments of CAR and DBF are parallel to the C2 symmetry axis whereas the corresponding transition moment in FLU is perpendicular to this axis. Herzberg-Teller coupling involving the S2 state also has been observed in the spectra of higher vibronic bands of CAR and DBF. Possible reasons for these behaviors are discussed.

  13. Rotationally resolved S1<--S0 electronic spectra of fluorene, carbazole, and dibenzofuran: Evidence for Herzberg-Teller coupling with the S2 state

    NASA Astrophysics Data System (ADS)

    Yi, John T.; Alvarez-Valtierra, Leonardo; Pratt, David W.

    2006-06-01

    Rotationally resolved fluorescence excitation spectra of the S1←S0 origin bands and higher vibronic bands of fluorene (FLU), carbazole (CAR), and dibenzofuran (DBF) have been observed and assigned. Analyses of these data show that replacement of the CH2 group in FLU with a NH group in CAR and an O atom in DBF produces only localized changes in structure, in the ground state. But the three molecules exhibit different changes in geometry when they are excited by light. The S1 states of the three molecules also are electronically very different. The S1←S0 transition moments of CAR and DBF are parallel to the C2 symmetry axis whereas the corresponding transition moment in FLU is perpendicular to this axis. Herzberg-Teller coupling involving the S2 state also has been observed in the spectra of higher vibronic bands of CAR and DBF. Possible reasons for these behaviors are discussed.

  14. (1+1) Resonant Enhanced Multiphoton Ionization Via the A 2 Sigma(+) State of NO: Ionic Rotational Branching Ratios and Their Intensity Dependence

    DTIC Science & Technology

    1988-02-01

    studies of diatomic mole- " atomic -like" model, in which the 3sa Rydberg state jc~ts a cules (H2, NO, CO, N2, 12),"" exploiting their less con...the PES detectoes have been refined to a point more complex and that the " atomic " picture may be mnade-P where the rotational structure of the ion can...I wave is pre- basis set.2 dicted to be dominant in an atomic -like model, and hence Finally, the Mi-resolved photoelectron distribution AN is even

  15. Rotational frequencies of transition metal hydrides for astrophysical searches in the far-infrared

    NASA Technical Reports Server (NTRS)

    Brown, John M.; Beaton, Stuart P.; Evenson, Kenneth M.

    1993-01-01

    Accurate frequencies for the lowest rotational transitions of five transition metal hydrides (CrH, FeH, CoH, NiH, and CuH) in their ground electronic states are reported to help the identification of these species in astrophysical sources from their far-infrared spectra. Accurate frequencies are determined in two ways: for CuH, by calculation from rotational constants determined from higher J transitions with an accuracy of 190 kHz; for the other species, by extrapolation to zero magnetic field from laser magnetic resonance spectra with an accuracy of 0.7 MHz.

  16. Rotational frequencies of transition metal hydrides for astrophysical searches in the far-infrared

    NASA Technical Reports Server (NTRS)

    Brown, John M.; Beaton, Stuart P.; Evenson, Kenneth M.

    1993-01-01

    Accurate frequencies for the lowest rotational transitions of five transition metal hydrides (CrH, FeH, CoH, NiH, and CuH) in their ground electronic states are reported to help the identification of these species in astrophysical sources from their far-infrared spectra. Accurate frequencies are determined in two ways: for CuH, by calculation from rotational constants determined from higher J transitions with an accuracy of 190 kHz; for the other species, by extrapolation to zero magnetic field from laser magnetic resonance spectra with an accuracy of 0.7 MHz.

  17. Unsteady Aerodynamic Response of Oscillating Contra-Rotating Annular Cascades Part II: Numerical Study

    NASA Astrophysics Data System (ADS)

    Nishino, Ryohei; Namba, Masanobu

    The unsteady aerodynamic force and work for contra-rotating annular cascades of oscillating blades are numerically investigated. A comparison among frequency components of unsteady blade loadings on oscillating blades and stationary blades in relative rotational motion is conducted. It is proved that the state of generated acoustic duct mode of the lowest order is a key factor governing the aeroacoustic interaction between the blade rows. The effect of the neighboring blade row on the aerodynamic force and work is never small and will make substantial modifications to the flutter boundaries of an isolated blade row.

  18. Rotating Wavepackets

    ERIC Educational Resources Information Center

    Lekner, John

    2008-01-01

    Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

  19. Rotating Wavepackets

    ERIC Educational Resources Information Center

    Lekner, John

    2008-01-01

    Any free-particle wavepacket solution of Schrodinger's equation can be converted by differentiations to wavepackets rotating about the original direction of motion. The angular momentum component along the motion associated with this rotation is an integral multiple of [h-bar]. It is an "intrinsic" angular momentum: independent of origin and…

  20. Unifying the rotational and permutation symmetry of nuclear spin states: Schur-Weyl duality in molecular physics.

    PubMed

    Schmiedt, Hanno; Jensen, Per; Schlemmer, Stephan

    2016-08-21

    In modern physics and chemistry concerned with many-body systems, one of the mainstays is identical-particle-permutation symmetry. In particular, both the intra-molecular dynamics of a single molecule and the inter-molecular dynamics associated, for example, with reactive molecular collisions are strongly affected by selection rules originating in nuclear-permutation symmetry operations being applied to the total internal wavefunctions, including nuclear spin, of the molecules involved. We propose here a general tool to determine coherently the permutation symmetry and the rotational symmetry (associated with the group of arbitrary rotations of the entire molecule in space) of molecular wavefunctions, in particular the nuclear-spin functions. Thus far, these two symmetries were believed to be mutually independent and it has even been argued that under certain circumstances, it is impossible to establish a one-to-one correspondence between them. However, using the Schur-Weyl duality theorem we show that the two types of symmetry are inherently coupled. In addition, we use the ingenious representation-theory technique of Young tableaus to represent the molecular nuclear-spin degrees of freedom in terms of well-defined mathematical objects. This simplifies the symmetry classification of the nuclear wavefunction even for large molecules. Also, the application to reactive collisions is very straightforward and provides a much simplified approach to obtaining selection rules.