Orbital rotation in the lowest triplet state of benzophenone
Dinse, K.P.; Pratt, D.W.
1982-04-07
Optically detected magnetic resonance (ODMR) and electron-nuclear double resonance (ODENDOR) spectroscopy at both zero and high magnetic fields were used to examine single crystals of 4,4'-dibromodiphenyl ether (DOE) containing 0.1 mol % of an enriched perdeuterio (/sup 17/O) benzophenone (/sup 17/O-BP-d/sub 10/) guest. Representative spectra are presented and explanations are offered for the electron spin transitions. The summarized results indicate the currently used atomic orbital functions do not provide an accurate description of the lowest excited states of many aromatic carbonyls. (BLM)
Lowest Vibrational States of Acrylonitrile
NASA Astrophysics Data System (ADS)
Kisiel, Zbigniew; Martin-Drumel, Marie-Aline; Pirali, Olivier
2015-06-01
Recent studies of the broadband rotational spectrum of acrylonitrile, H_2C=CHC≡N, revealed the presence of multiple resonances between rotational levels in different vibrational states. The resonances affect even the ground state transitions and their analysis allowed determination of vibrational term values for the first three excited states above the ground state and of vibrational energy differences in several polyads above these states. At that time there was no infrared data of sufficient resolution to assess the reliability of the resonance based vibrational energy determinations. We presently report results based on a 40-700 cm-1 high-resolution spectrum of acrylonitrile recorded at the AILES beamline of the SOLEIL synchrotron. This spectrum was reduced by using the AABS packagea, and allowed assignment of vibration-rotation transitions in four fundamentals, five hot bands, and one overtone band. The infrared data and previous measurements made with microwave techniques have been combined into a single global fit encompassing over 31000 measured transitions. Precise vibrational term values have been determined for the eight lowest excited vibrational states. The new results validate the previous estimates from rotational perturbations and are also compared with results of ab~initio anharmonic force field calculations. Z. Kisiel, et al., J. Mol. Spectrosc. 280 134 (2012). A. López, et al., Astron. & Astrophys. 572, A44 Z. Kisiel, et al., J. Mol. Spectrosc. 233 231 (2005).
Waeckerle, G.; Baer, M.; Zimmermann, H.; Dinse, K.H.; Yamauchi, S.; Kashmar, R.J.; Pratt, D.W.
1982-03-01
The magnetically active isotope of oxygen /sup 17/O has been used to probe the changes in the electron charge and spin density distributions in oxygen valence orbitals which occur when benzophenone is excited to its lowest triplet state. The data obtained include the optically detected magnetic resonance (ODMR) and electron-nuclear double resonance spectra at both zero and high magnetic fields. New methods of analysis of zero-field ODMR spectra, appropriate when the second-order hyperfine splitting exceeds the quadrupole coupling, are described. This analysis yields the principal values of the electron fine-structure (D), oxygen hyperfine (A), and oxygen quadrupole (Q) tensors, and the orientation of their principal axes with respect to the molecular frame. It is found, consistent with expectations for an n..pi..( state, that the direction of the largest component of Q is different from that of the ground state. It is also found, by two independent methods, that the principal transverse axes of A and Q do not conform to the local C/sub 2v/ symmetry axes of the carbonyl group. This result is interpreted to mean that the axis of the n-type oxygen 2p orbital is rotated out of the carbonyl plane, a rotation which appears to be direct consequence of n..pi..(/..pi pi..( configurational mixing. In agreement with this, the principal values of D, A, and Q are different from those expected for a ''pure'' n..pi..( state. Other consequences of n..pi..(/..pi pi..( mixing, not only in benzophenone but also in the lowest triplet states of other aromatic carbonyls, are discussed briefly.
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.
Takekoshi, T.; Lang, F.; Strauss, C.; Denschlag, J. Hecker; Lysebo, Marius; Veseth, Leif
2011-06-15
We present the results of an experimental and theoretical study of the electronically excited (1){sup 3{Sigma}}{sub g}{sup +} state of {sup 87}Rb{sub 2} molecules. The vibrational energies are measured for deeply bound states from the bottom up to v{sup '}=15 using laser spectroscopy of ultracold Rb{sub 2} Feshbach molecules. The spectrum of each vibrational state is dominated by a 47-GHz splitting into 0{sub g}{sup -} and 1{sub g} components caused mainly by a strong second-order spin-orbit interaction. Our spectroscopy fully resolves the rotational, hyperfine, and Zeeman structure of the spectrum. We are able to describe this structure to the first order using a simplified effective Hamiltonian.
Potential energy curves for the 48 lowest-lying molecular states of LiH +
NASA Astrophysics Data System (ADS)
Alikacem, A.; Aubert-Frécon, M.
1985-05-01
The electronic energies of the 20 lowest lying 2Σ + states, the 14 lowest lying 2Π states, and the 14 lowest lying 2Δ states of LiH + have been calculated in the range 2 ≤ R ≤ 20 a.u. from a model potential approach and using truncated diatomic orbitals (TDO) as basis set. Results in very good agreement with the more recent literature were obtained for the spectroscopic constants, Re and De, for the ground state X2Σ +.
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.
Jansen, Paul; Semeria, Luca; Hofer, Laura Esteban; Scheidegger, Simon; Agner, Josef A; Schmutz, Hansjürg; Merkt, Frédéric
2015-09-25
Multistage Zeeman deceleration was used to generate a slow, dense beam of translationally cold He_{2} molecules in the metastable a ^{3}Σ_{u}^{+} 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 He_{2} and the lowest rotational interval of the X^{+} ^{2}Σ_{u}^{+} (ν^{+}=0) ground state of ^{4}He_{2}^{+} have been determined with unprecedented precision and accuracy by Rydberg-series extrapolation. Comparison with ab initio predictions of the rotational energy level structure of ^{4}He_{2}^{+} [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 He_{2}^{+}. PMID:26451553
Representation of the Heisenberg Algebra h4 by the Lowest Landau Levels and Their Coherent States
NASA Astrophysics Data System (ADS)
Fakhri, H.; Shadman, Z.
Using simultaneous shape invariance with respect to two different parameters, we introduce a pair of appropriate operators which realize shape invariance symmetry for the monomials on a half-axis. It leads to the derivation of rotational symmetry and dynamical symmetry group H4 with infinite-fold degeneracy for the lowest Landau levels. This allows us to represent the Heisenberg-Lie algebra h4 not only by the lowest Landau levels, but also by their corresponding standard coherent states.
The Ground and Two Lowest-lying Singlet Excited Electronic States of Copper Hydroxide (CuOH)
Wang, Suyun; Paul, Ankan; DeYonker, Nathan John; Yamaguchi, Yukio; Schaefer, Henry F
2005-07-12
The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. Various ab initio methods, including self-consistent field (SCF), configuration interaction, coupled cluster (CC), and complete-active-space SCF (CASSCF), have been employed to study the electronic structure of copper hydroxide (CuOH). Geometries, total energies, dipole moments, harmonic vibrational frequencies, and zero-point vibrational energies are reported for the linear^{ 1}Σ^{+} and 1Π stationary points, and for the bent ground-state X˜ ^{1}A', and excited-states 2 ^{1}A" and 1^{ 1}A". Six different basis sets have been used in the study, Wachters/DZP being the smallest and QZVPP being the largest. The ground- and excited-state bending modes present imaginary frequencies for the linear stationary points, indicating that bent structures are more favorable. The effects of relativity for CuOH are important and have been considered using the Douglas–Kroll approach with cc-pVTZ/cc-pVTZ_DK and cc-pVQZ/cc-pVQZ_DK basis sets. The bent ground and two lowest-lying singlet excited states of the CuOH molecule are indeed energetically more stable than the corresponding linear structures. The optimized geometrical parameters for the X˜ ^{1}A' and 1 ^{1}A" states agree fairly well with available experimental values. However, the 2 ^{1}A' structure and rotational constants are in poor agreement with experiment, and we suggest that the latter are in error. The predicted adiabatic excitation energies are also inconsistent with the experimental values of 45.5 kcal mol^{-1} for the 2 ^{1}A' state and 52.6 kcal mol^{-1} for the 1^{ 1}A" state. The theoretical CC and CASSCF methods show lower
Zhu, Jun; Fogarty, Heather A; Möllerstedt, Helene; Brink, Maria; Ottosson, Henrik
2013-08-01
A density functional theory study on olefins with five-membered monocyclic 4n and 4n+2 π-electron substituents (C4H3X; X=CH(+), SiH(+), BH, AlH, CH2, SiH2, O, S, NH, and CH(-)) was performed to assess the connection between the degree of substituent (anti)aromaticity and the profile of the lowest triplet-state (T1) potential-energy surface (PES) for twisting about olefinic C=C bonds. It exploited both Hückel's rule on aromaticity in the closed-shell singlet ground state (S0) and Baird's rule on aromaticity in the lowest ππ* excited triplet state. The compounds CH2=CH(C4H3X) were categorized as set A and set B olefins depending on which carbon atom (C2 or C3) of the C4H3X ring is bonded to the olefin. The degree of substituent (anti)aromaticity goes from strongly S0 -antiaromatic/T1 -aromatic (C5H4 (+)) to strongly S0 -aromatic/T1- antiaromatic (C5H4(-)). Our hypothesis is that the shapes of the T1 PESs, as given by the energy differences between planar and perpendicularly twisted olefin structures in T1 [ΔE(T1)], smoothly follow the changes in substituent (anti)aromaticity. Indeed, correlations between ΔE(T1) and the (anti)aromaticity changes of the C4 H3 X groups, as measured by the zz-tensor component of the nucleus-independent chemical shift ΔNICS(T1;1)zz , are found both for sets A and B separately (linear fits; r(2) =0.949 and 0.851, respectively) and for the two sets combined (linear fit; r(2) =0.851). For sets A and B combined, strong correlations are also found between ΔE(T1) and the degree of S0 (anti)aromaticity as determined by NICS(S0,1)zz (sigmoidal fit; r(2) =0.963), as well as between the T1 energies of the planar olefins and NICS(S0,1)zz (linear fit; r(2) =0.939). Thus, careful tuning of substituent (anti)aromaticity allows for design of small olefins with T1 PESs suitable for adiabatic Z/E photoisomerization. PMID:23794153
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.
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.
Analysis of the three lowest bending frequencies of a rotating propeller
NASA Technical Reports Server (NTRS)
Liebers, F
1936-01-01
The available literature on rotating propeller oscillations reveals a lack of uniformity in interpretation, particularly as concerns the data on the overtone frequency with respect to the centrifugal forces. The present report is a survey of the existing data for computing the bending frequency and a check on the dependability of the calculating methods.
Theoretical prediction of the potential curves for the lowest-lying states of the C2 + molecular ion
NASA Astrophysics Data System (ADS)
Petrongolo, Carlo; Bruna, Pablo J.; Peyerimhoff, Sigrid D.; Buenker, Robert J.
1981-04-01
Ab initio MRD-CI potential curves have been calculated for C2+ in its first 16 electronic states and vertical transition energies Tv have been computed for a number of higher-lying species, all of which correlate with the first dissociation limit C(3Pg)+C+(2Pu). The ground state of this molecular ion is found to be X 4Σg- while the first excited state is 1 2Πu, with a calculated Te value of 0.84 eV. On the basis of this work the C2 I.P. value known experimentally is ascribed to the a 3Πu→1 2Πu process while the transition involving both ground states appears to be difficult to detect experimentlly. Thus, the measured De value for C+2 should involve fragmentation of the 1 2Πu states as well. A comparison with previous calculations which attempt to estimate the correlation energies of the various C+2 states in a semiempirical manner shows very large discrepancies, both in the transition energies themselves and in the ordering of these states. Finally the assignment for the Meinel experimental band system at 4.98 eV as a 2Σ-g←2Πu transition in C+2 is not supported by the present theoretical study.
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).
Stretching of hydrogen-bonded OH in the lowest singlet excited electronic state of water dimer.
Chipman, Daniel M
2006-01-28
The lowest singlet excited electronic state of water monomer in the gas phase is strictly dissociative along a OH stretch coordinate but changes its nature when the stretched OH moiety is hydrogen bonded to a neighboring water molecule. This work extends previous exploration of the water dimer excited singlet potential-energy surface, using computational methods that are reliable even at geometries well removed from the ground-state equilibrium. First, the hydrogen-bonded OH moiety is stretched far enough to establish the existence of a barrier that is sufficient to support a quasibound vibrational state of the OH oscillator near the Franck-Condon region. Second, the constraint of an icelike structure is relaxed, and it is found that a substantial fraction of liquidlike structures also supports a quasibound vibrational state. These potential-energy explorations on stretching of the hydrogen-bonded OH moiety in a water dimer are discussed as a model for understanding the initial dynamics upon excitation into the lowest excited singlet state of condensed water. The possibility is raised that the excited-state lifetime may be long enough to allow for exciton migration, which would provide a mechanism for energy transport in condensed water phases. PMID:16460160
Oh, Juwon; Sung, Young Mo; Kim, Woojae; Mori, Shigeki; Osuka, Atsuhiro; Kim, Dongho
2016-05-23
The aromaticity reversal in the lowest triplet state (T1 ) of a comparable set of Hückel/Möbius aromatic metalated expanded porphyrins was explored by optical spectroscopy and quantum calculations. In the absorption spectra, the T1 states of the Möbius aromatic species showed broad, weak, and ill-defined spectral features with small extinction coefficients, which is in line with typical antiaromatic expanded porphyrins. In combination with quantum calculations, these results indicate that the Möbius aromatic nature of the S0 state is reversed to Möbius antiaromaticity in the T1 state. This is the first experimental observation of aromaticity reversal in the T1 state of Möbius aromatic molecules. PMID:27079620
Testing quantum electrodynamics in the lowest singlet state of neutral beryllium-9
NASA Astrophysics Data System (ADS)
Williams, Will; Cao, Melody; Kaplan, Emily
2016-05-01
We present high precision spectroscopic results on the 2s2p J = 1 singlet state in neutral beryllium-9. Combined with theoretical predictions this measurement serves as a test of quantum electrodynamics and various theoretical methods for predicting the energy of this state. Our experimental setup consists of an oven at 1200C that produces a beam of beryllium atoms. The singlet state is probed transverse to the atomic beam with 235nm light from a frequency quadrupled titanium sapphire laser, where the frequency doubled light at 470nm is stabilized to an ultra low expansion cavity. We also present our progress on spectroscopy on the lowest triplet states and the ionization threshold.
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.
Fragile Fractional Quantum Hall States in the Lowest and the Second Landau Level
NASA Astrophysics Data System (ADS)
Csathy, Gabor; Kleinbaum, Ethan; Kumar, Ashwani; Samkharadze, Nodar; Pfeiffer, Loren; West, Ken
Ultra-low temperature measurements of the two-dimensional electron gas have revealed some of the most fragile fractional quantum Hall states. In these experiments electron thermalization was achieved using a He-3 immersion cell and the temperature of the bath is monitored using a quartz tuning fork viscometer. We will review the recently discovered fractional quantum Hall state at filling factor ν = 3 + 1 / 3 observed in the second Landau level and those at the filling factor ν = 4 / 11 and 5 / 13 in the lowest Landau level. The work at Purdue was supported by NSF DMR 1207375 and 1505866 grants. The work at Princeton University was funded by the Gordon and Betty Moore Foundation through the EPiQS initiative Grant GBMF4420, and by the National Science Foundation MRSEC Grant DMR-1420541.
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.
A diabatic representation of the two lowest electronic states of Li{sub 3}
Ghassemi, Elham Nour; Larson, Jonas; Institut für Theoretische Physik, Universität zu Köln, Köln De-50937 ; Larson, Åsa
2014-04-21
Using the Multi-Reference Configuration Interaction method, the adiabatic potential energy surfaces of Li{sub 3} are computed. The two lowest electronic states are bound and exhibit a conical intersection. By fitting the calculated potential energy surfaces to the cubic E ⊗ ε Jahn-Teller model we extract the effective Jahn-Teller parameters corresponding to Li{sub 3}. These are used to set up the transformation matrix which transforms from the adiabatic to a diabatic representation. This diabatization method gives a Hamiltonian for Li{sub 3} which is free from singular non-adiabatic couplings and should be accurate for large internuclear distances, and it thereby allows for bound dynamics in the vicinity of the conical intersection to be explored.
Isotope effects of ground and lowest lying vibrational states of H3-xDxO2 (-) complexes.
Ansari, Narjes; Meyer, Hans-Dieter
2016-02-01
Isotope effects of the H3O2 (-) anion are investigated. For this, the 24 lowest excited vibrational states of the H3-xDxO2 (-) 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. PMID:26851922
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.
Anisotropic Quantum Hall Liquid States with No Translational Invariance in the Lowest Landau Level
NASA Astrophysics Data System (ADS)
Ciftja, Orion
2016-05-01
Strongly correlated two-dimensional electron systems in a high perpendicular magnetic field have displayed remarkable new physics leading to the discovery of phenomena such as the integer and the fractional quantum Hall effect, to mention a few. Laughlin's theoretical model and the composite fermion's (CFs) approach provide a good description of the liquid electronic phases in the lowest Landau level (LLL) at relatively large filling factors. Other electronic phases at smaller filling factors of the LLL likely represent electronic Wigner solid states. It is believed that no other phases with intermediate order stabilize at the liquid-solid transition region. The current study deals with filling factor 1/6 in the LLL, a state which is very close to the critical filling factor where the liquid-solid transition takes place. With the assumption that the underlying signs of crystalline order are starting to appear at this transitional regime, we focus our attention and study the properties of a hybrid electronic phase that lacks translational invariance. To describe such a state, we consider a wave function that lies entirely in the LLL but, unlike a typical quantum Hall liquid phase, does not possess translational invariance. Although inspired by Laughlin's approach, the wave function we introduce differs from Laughlin's or CFs wave functions that describe translationally invariant uniform electronic phases. We perform quantum Monte Carlo simulations in a standard disk geometry to gain a better understanding of the properties of this wave function that may be considered as a precursor to the more conventional Wigner crystal phase.
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. PMID:26176891
Analysis of the Lowest In-Plane Bend and First Excited Torsional State of CH_3CH_2CN
NASA Astrophysics Data System (ADS)
Brauer, Carolyn S.; Pearson, John C.; Drouin, Brian J.; Yu, Shanshan
2009-06-01
Propionitrile (CH_3CH_2CN) is observed with large column densities in a number of high-mass star-forming cores, where core temperatures exceed 200 K. It is a near-prolate (κ=0.96) asymmetric top with appreciable dipole moment components on both the a- and b-axes (μ_a = 3.84 D, μ_b = 1.23 D). This, combined with the presence of four fundamental modes as well as four overtones and combination bands all occurring below 600 cm^{-1}, results in a very rich spectrum. It is known to be a major contributor to spectral line confusion in ground-based observations and is expected to complicate observations by Herschel, SOFIA and ALMA, making it imperative to fully characterize the entire spectrum. The lowest in-plane bend, ν_{13}, is 206.9(0.5) cm^{-1}, and the first excited torsional state, ν_{21}, which is just 186 GHz above, have been detected in hot cores with antenna temperatures of a few Kelvin. The close proximity of ν_{13} and ν_{21}, as well as their low-lying nature, offers a unique opportunity to study the vibration-torsion-rotation coupling problem in the case of two nearly degenerate vibrational states. As expected from C_s symmetry and their A^' and A^'' nature, these states exhibit strong a- and b-symmetry Coriolis interactions, as well as interactions resulting from different sets of Eckhart-Sayvetz conditions being required in ν_{13} and ν_{21}. In the present work, the ν_{13} and ν_{21} states of propionitrile have been analyzed to high frequency and angular momentum quantum number. The spectrum, molecular constants,and insights into the vibration-torsion-rotation problem will be discussed. H. M. Heise, H. Lutz & H. Dreizler,Z.Nat.,29a,1345 (1974). H. M. Heise, F. Winther & H. Lutz,J. Mol. Spectrosc.,90,531 (1981). D. M. Mehringer, J. C. Pearson, J. Keene & T. G. Phillips,Ap.J.,608,306 (2004).
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.
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…
Shape vibration and quasiparticle excitations in the lowest 0+ excited state in erbium isotopes
NASA Astrophysics Data System (ADS)
Chen, Fang-Qi; Egido, J. Luis
2016-06-01
The ground and first excited 0+ states of the -172Er156 isotopes are analyzed in the framework of the generator coordinate method. The shape parameter β is used to generate wave functions with different deformations which together with the two-quasiparticle states built on them provide a set of states. An angular momentum and particle number projection of the latter spawn the basis states of the generator coordinate method. With this ansatz and using the separable pairing plus quadrupole interaction we obtain a good agreement with the experimental spectra and E 2 transition rates up to moderate spin values. The structure of the wave functions suggests that the first excited 0+ states in the soft Er isotopes are dominated by shape fluctuations, while in the well deformed Er isotopes the two-quasiparticle states are more relevant. In between, both degrees of freedom are necessary.
NASA Astrophysics Data System (ADS)
Amberger, Brent K.; Woods, R. Claude; Esselman, Brian J.; McMahon, Robert J.
2015-06-01
Hydrazoic acid (HN_3) is a near-prolate asymmetric top molecule which we have extensively studied in the millimeter-wave region. Having completed an Re structure determination based on 14 isotopologues of HN_3, we have moved on to analyze the very complex rotational spectra for the first 7 vibrationally excited states, as well as the higher K levels of the ground vibrational state. The excited states include the 4 lowest (out of 6) fundamental modes (νb{5}, νb{6}, νb{4}, and νb{3}) and the 3 lowest combination and overtone states (2νb{5}, 2νb{6} and νb{5}+νb{6}). All of these states are totally symmetric (A') except for νb{6} and νb{5}+νb{6}, which are antisymmetric (A"). The ro-vibrational states are substantially more intermingled than in most molecules due to unusually wide rotational spacing in HN_3. This intermingling leads to a tangled web of perturbations connecting the various ro-vibrational states: a-type and b-type Coriolis interactions between νb{5} and νb{6}, between νb{4} and νb{6}, and between 2νb{6} or 2νb{5} and νb{5}+νb{6}, local Fermi resonance between νb{3} and 2νb{6}, and a strong centrifugal distortion interaction between the ground state and νb{5}. Fortunately, we have been able to make extensive use (in both assignment of spectra and fitting of spectroscopic parameters) of previously published high resolution FTIR data for the νb{5}, νb{6}, νb{4} and νb{3} bands and the pure rotational spectrum of the ground vibrational state. For the ground state, a-type R-branches from K = 0 to K = 9 and J = 9 through J = 19 and b-type transitions with K = 0 through K = 2 and J values up to 56 have been assigned. The datasets for most other states are similarly extensive. Combined millimeter-wave/FTIR multi-state fits have been performed using Pickett's SPFIT program. J. Bendtsen, F. Hegelund and F. M. Nicolaisen, J. Mol. Spectrosc. 118, 121 (1986) J. Bendtsen and F. M. Nicolaisen, J. Mol. Spectrosc. 119, 456 (1986) J. Bendtsen and
An ab initio study of the lowest electronic states of yttrium dicarbide, YC2
NASA Astrophysics Data System (ADS)
Puzzarini, Cristina; Peterson, Kirk A.
2005-02-01
The low-lying electronic states of yttrium dicarbide have been calculated using highly correlated wave functions and systematic sequences of correlation consistent basis sets. For the A12 ground electronic state, the near-equilibrium potential energy surface (PES) has been calculated using the coupled cluster method in conjunction with basis sets ranging in size from double to quintuple ζ. The relativistic effects have been taken into account by using pseudopotentials for the Y atom. After extrapolation to the complete basis set limit, additional corrections due to core-valence correlation and spin-orbit effects have also been included. The same approach has been followed for the B12,B22, and A22 states but only the C2V PESs have been considered in these cases. For the two A12 electronic excited states and, for comparison purposes, for the ground state, the multireference configuration interaction (MRCI) approach has been used in conjunction with double-ζ and triple-ζ basis sets for the construction of the PES. The molecular and spectroscopic properties predicted for the ground and excited states investigated in this work compare well with the available experimental data, particularly for the ground electronic state. The 0 K dissociation enthalpy of YC2,ΔHY-C2(0K ), and its atomization enthalpy, ΣD0, are predicted to be 148.4 and 291.5kcal /mol, respectively.
NASA Astrophysics Data System (ADS)
Perez, Cristobal; Muckle, Matt T.; Zaleski, Daniel P.; Seifert, Nathan; Pate, Brooks H.; Kisiel, Zbigniew; Temelso, Berhane; Shields, George C.
2012-06-01
The water hexamer is predicted to be the smallest water cluster with a three-dimensional hydrogen bonding network as its minimum energy structure. Calculations indicate that there are several possible low-energy isomers, with different levels of theory identifying different isomers as the global minimum. Previous experimental work has provided evidence for the cage, book, and cyclic isomers but no experiment has identified multiple coexisting structures. Using broadband rotational spectroscopy in pulsed supersonic expansion these three isomers have now been unambiguously identified and their oxygen framework structures determined by means of H_218O substitution. Relative isomer populations at different expansion conditions establish that the cage isomer is the minimum energy structure. The comparison of experimental and theoretical rotational constants shows that significant improvement in the agreement is achieved when vibrationally averaged (0 K) theoretical structures are used. For the water hexamer isomers, only the prism shows effects from tunneling associated with the rearrangement of the H-bond network. This tunneling is quenched upon the incorporation of a single H_218O monomer into the prism cluster. Rotational spectra consistent with predictions for the lowest energy heptamer and nonamer structures have also been identified and the structure of the heptamer oxygen atom framework has also been determined using H_218O substitution.
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.
NASA Astrophysics Data System (ADS)
Mukhopadhyay, Indra
2016-05-01
In this work the far infrared (FIR) absorption spectrum has been measured for the asymmetrically mono deuterated Methanol (CH2DOH) species in the wavenumber range of 15-1200 cm-1 better accuracy and signal/noise ratio than known before. Assignments have been made for b-type transitions in the lowest lying torsional vibrational state trans-(e0) for a wide range of rotational angular momentum. The assignments have been rigorously confirmed by the residual loop defect methods. The rR-branch wavenumbers are analyzed by the usual state dependent expansion parameters and the Q-Branch origins. These origins have been used to calculate the torsional and torsional-rotation interaction contributions. These findings are in good agreement with predicted from the Hamiltonian model described in recent publications. A large number of assignments have also been made in the millimeter wave spectrum recorded earlier and thereby evaluated the asymmetry splitting parameters for 4 different axial rotational angular momentum quantum numbers. The analysis and interpretation of the spectra are reported. New assignments for about 260 transitions are included the text and a catalog of about 1500 transitions belonging to the e0 species is prepared (Appendix 1) and is made available through the open server in "Research Gate" and will be freely available to others.
The lowest-energy charge-transfer state and its role in charge separation in organic photovoltaics.
Nan, Guangjun; Zhang, Xu; Lu, Gang
2016-06-29
Energy independent, yet higher than 90% internal quantum efficiency (IQE), has been observed in many organic photovoltaics (OPVs). However, its physical origin remains largely unknown and controversial. The hypothesis that the lowest charge-transfer (CT) state may be weakly bound at the interface has been proposed to rationalize the experimental observations. In this paper, we study the nature of the lowest-energy CT (CT1) state, and show conclusively that the CT1 state is localized in typical OPVs. The electronic couplings in the donor and acceptor are found to determine the localization of the CT1 state. We examine the geminate recombination of the CT1 state and estimate its lifetime from first principles. We identify the vibrational modes that contribute to the geminate recombination. Using material parameters determined from first principles and experiments, we carry out kinetic Monte Carlo simulations to examine the charge separation of the localized CT1 state. We find that the localized CT1 state can indeed yield efficient charge separation with IQE higher than 90%. Dynamic disorder and configuration entropy can provide the energetic and entropy driving force for charge separation. Charge separation efficiency depends more sensitively on the dimension and crystallinity of the acceptor parallel to the interface than that normal to the interface. Reorganization energy is found to be the most important material parameter for charge separation, and lowering the reorganization energy of the donor should be pursued in the materials design. PMID:27306609
Wasilewski, J.; Staemmler, V.; Koch, S.
1988-08-01
Extensive ab initio calculations at coupled-electron-pair approximation and multireference configuration interaction levels have been performed for the two lowest states X /sup 2/..sigma../sup +/ and A/sup 2/Pi of HeNe/sup +/. Spin-orbit coupling has been included on a semiempirical basis in order to account for the strong mixing between the X /sup 2/..sigma../sub 1/2//sup +/ and A/sub 2//sup 2/Pi/sub 1/2/ components, which influences the properties of both these states in the experimentally observed region at large internuclear distances.
Dynamics of molecules in extreme rotational states
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.
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.
NASA Astrophysics Data System (ADS)
Ding, Yun; Ulenikov, O. N.; Bekhtereva, E. S.; Zheng, Jing-Jing; He, Sheng-Gui; Wang, Xiang-Huai; Hu, Shui-Ming; Zhu, Qing-Shi
2001-10-01
The high-resolution Fourier transform spectrum of the DO35Cl molecule was recorded and analyzed in the region of the two lowest D-O overtone bands, 2ν1 and 3ν1. Because of the presence of strong resonance interactions, the influence of the (130) state on the (200) state, and also that of the (221), (230) states on the (300) sate, was taken into account. Transitions belonging to the 2ν1 and 3ν1 bands were assigned up to Jmax.=35 in both cases. The sets of spectroscopic parameters and resonance coefficients obtained from the fit reproduce the 'experimental' rovibrational energies of the (200) and (300) vibrational states with accuracies close to experimental uncertainties.
Lowest vibrational states of {sup 4}He{sup 3}He{sup +}: Non-Born-Oppenheimer calculations
Stanke, Monika; Bubin, Sergiy; Kedziera, Dariusz; Molski, Marcin; Adamowicz, Ludwik
2007-11-15
Very accurate quantum mechanical calculations of the first five vibrational states of the {sup 4}He{sup 3}He{sup +} molecular ion are reported. The calculations have been performed explicitly including the coupling of the electronic and nuclear motions [i.e., without assuming the Born-Oppenheimer (BO) approximation]. The nonrelativistic non-BO wave functions were used to calculate the {alpha}{sup 2} relativistic mass velocity, Darwin, and spin-spin interaction corrections. For the lowest vibrational transition, whose experimental energy is established with high precision, the calculated and the experimental results differ by only 0.16 cm{sup -1}.
Measurement of the lifetimes of the lowest {sup 3}P{sub 1} state of neutral Ba and Ra
Scielzo, N. D.; Guest, J. R.; Schulte, E. C.; Ahmad, I.; Bailey, K.; Holt, R. J.; O'Connor, T. P.; Potterveld, D. H.; Bowers, D. L.; Lu, Z.-T.
2006-01-15
The lifetimes of the lowest {sup 3}P{sub 1} states of Ba and Ra were determined to be 1345{+-}14 ns and 422{+-}20 ns, respectively, by measuring the exponential decay of fluorescence after illuminating a thermal atomic beam with pulses of laser light. In addition, the {sup 1}S{sub 0}(F=1/2)-{sup 3}P{sub 1}(F=3/2) transition frequency in {sup 225}Ra was measured to be 13 999.269{+-}0.001 cm{sup -1} by referencing a nearby I{sub 2} transition.
Measurements of the lifetime of the lowest {sup 3}P{sub 1} state of neutral Ba and Ra.
Scielzo, N. D.; Guest, J. R.; Schulte, E. C.; Ahmad, I.; Bailey, K.; Bowers, D. L.; Holt, R. J.; Lu, Z.-T.; O'Connor, T.; Potterveld, D. H.; Univ. of Chicago
2006-01-01
The lifetimes of the lowest {sup 3}P{sub 1} states of Ba and Ra were determined to be 1345 {+-} 14 ns and 422 {+-} 20 ns, respectively, by measuring the exponential decay of fluorescence after illuminating a thermal atomic beam with pulses of laser light. In addition, the {sup 1}S{sub 0}(F=1/2)-{sup 3}P{sub 1}(F=3/2) transition frequency in {sup 225}Ra was measured to be 13 999.269 {+-} 0.001 cm{sup -1} by referencing a nearby I{sub 2} transition.
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.
Synchronous states of slowly rotating pendula
NASA Astrophysics Data System (ADS)
Kapitaniak, Marcin; Czolczynski, Krzysztof; Perlikowski, Przemysław; Stefanski, Andrzej; Kapitaniak, Tomasz
2014-08-01
Coupled systems that contain rotating elements are typical in physical, biological and engineering applications and for years have been the subject of intensive studies. One problem of scientific interest, which among others occurs in such systems is the phenomenon of synchronization of different rotating parts. Despite different initial conditions, after a sufficiently long transient, the rotating parts move in the same way - complete synchronization, or a permanent constant shift is established between their displacements, i.e., the angles of rotation - phase synchronization. Synchronization occurs due to dependence of the periods of rotating elements motion and the displacement of the base on which these elements are mounted. We review the studies on the synchronization of rotating pendula and compare them with the results obtained for oscillating pendula. As an example we consider the dynamics of the system consisting of n pendula mounted on the movable beam. The pendula are excited by the external torques which are inversely proportional to the angular velocities of the pendula. As the result of such excitation each pendulum rotates around its axis of rotation. It has been assumed that all pendula rotate in the same direction or in the opposite directions. We consider the case of slowly rotating pendula and estimate the influence of the gravity on their motion. We classify the synchronous states of the identical pendula and observe how the parameters mismatch can influence them. We give evidence that synchronous states are robust as they exist in the wide range of system parameters and can be observed in a simple experiment.
Theoretical transition probabilities between the lowest 2S, 2P and 2D states of Na, K, Rb and Cs
NASA Technical Reports Server (NTRS)
Langhoff, S. R.; Bauschlicher, C. W., Jr.; Partridge, H.
1985-01-01
Theoretical transition probabilities between the lowest 2S, 2P and 2D states of the alkali atoms Na through Cs have been computed using near Hartree-Fock quality Slater basis sets. The important core-valence correlation effects are incorporated explicitly by a configuration-interaction procedure. For Cs, the calculations were repeated using a Gaussian basis set so that relativistic effects could be incorporated through an effective core potential procedure. The best calculated electric quadrupole Einstein coefficients are Na(196.3/s), K(103.6/s), Rb(72.4/s) and Cs(19.7/s). Core-valence effects become increasingly important down the column, and reduce the quadrupole transition strengths to about the same degree as for the 2P-2S and 2D-2P dipole-allowed transitions. Relativistic effects increase the quadrupole moment of Cs, but less so than in Ba, presumably because the alkali 2D states are more diffuse.
NASA Astrophysics Data System (ADS)
Dehghani, A.; Fakhri, H.
2011-02-01
The second lowest and second highest bases of the discrete positive and negative irreducible representations of su(1, 1) Lie algebra via spherical harmonics are used to construct generalized coherent states. Depending on whether the representation label is an even or odd integer, each of the new coherent states is separated into two different classes. They are constituted by appropriate superpositions of the increasing and decreasing infinite sequences with respect to the m index of the spherical harmonics {Ym2j ± m(θ, phi)}m = mnplusj ± 1±∞ and {Ym2k ± m - 1(θ, phi)}m = mnplusk ± 2±∞, and converge to the known functions. Also the non-oscillating measures to realize the resolution of the identity condition on the unit disk are calculated.
NASA Astrophysics Data System (ADS)
Bussery, Béatrice; Achkar, Yamina; Aubert-Frécon, Monique
1987-09-01
Long-range energy matrix elements have been calculated in the multipolar expansion approximation for all the molecular states dissociating to the three or four lowest asymptotes for the molecules LiNa, LiK, LiRb, LiCs, NaK, NaRb, NaCs, KRb, KCs and RbCs using the semi-empirical perturbative model we proposed recently. Two different assumptions have been investigated: including or excluding the spin-orbit effects within each atom. Full numerical results are presented for NaK and LiCs which have been chosen as examples. For the ten molecules in the non-interacting assumption the long-range coefficients C6 and C8 have been found for each state when neglecting atomic spin-orbit effects while the fitted value C*6 and C*8 are presented for each state when including atomic spin-orbit effects. When considering the interacting states, those dissociating to ns + n's and to ns + 5d(Cs) are seen to be slightly perturbed while the states dissociating to ns + n'p and to np + n's are significantly perturbed. The wavefunctions for the interacting 3Σ +, 3Π, 0 +, 0 -, 1, 2 states for the molecules NaK and LiCs are presented for various internuclear distances.
Study of Topological Effects Concerning the Lowest A″ and the Three A' States for the CO2(+) Ion.
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. PMID:26583700
NASA Astrophysics Data System (ADS)
Xavier, F. George D.; Kumar, Sanjay
2010-10-01
Ab initio global adiabatic and quasidiabatic potential energy surfaces of lowest four electronic (1-4 A3″) states of the H++O2 system have been computed in the Jacobi coordinates (R,r,γ) using Dunning's cc-pVTZ basis set at the internally contracted multireference (single and double) configuration interaction level of accuracy, which are relevant to the dynamics studies of inelastic vibrational and charge transfer processes observed in the scattering experiments. The computed equilibrium geometry parameters of the bound [HO2]+ ion in the ground electronic state and other parameters for the transition state for the isomerization process, HOO+⇌OOH+ are in good quantitative agreement with those available from the high level ab initio calculations, thus lending credence to the accuracy of the potential energy surfaces. The nonadiabatic couplings between the electronic states have been analyzed in both the adiabatic and quasidiabatic frameworks by computing the nonadiabatic coupling matrix elements and the coupling potentials, respectively. It is inferred that the dynamics of energy transfer processes in the scattering experiments carried out in the range of 9.5-23 eV would involve all the four electronic states.
Frank, H A; Bautista, J A; Josue, J S; Young, A J
2000-03-21
The xanthophyll cycle is an enzymatic, reversible process through which the carotenoids violaxanthin, antheraxanthin, and zeaxanthin are interconverted in response to the need to balance light absorption with the capacity to use the energy to drive the reactions of photosynthesis. The cycle is thought to be one of the main avenues for safely dissipating excitation energy absorbed by plants in excess of that needed for photosynthesis. One of the key factors needed to elucidate the molecular mechanism by which the potentially damaging excess energy is dissipated is the energy of the lowest excited singlet (S(1)) state of the xanthophyll pigments. Absorption from the ground state (S(0)) to S(1) is forbidden by symmetry, making a determination of the S(1) state energies of these molecules by absorption spectroscopy very difficult. Fluorescence spectroscopy is potentially the most direct method for obtaining the S(1) state energies. However, because of problems with sample purity, low emission quantum yields, and detection sensitivity, fluorescence spectra from these molecules, until now, have never been reported. In this work these technical obstacles have been overcome, and S(1) --> S(0) fluorescence spectra of violaxanthin and zeaxanthin are presented. The energies of the S(1) states deduced from the fluorescence spectra are 14 880 +/- 90 cm(-)(1) for violaxanthin and 14 550 +/- 90 cm(-)(1) for zeaxanthin. The results provide important insights into the mechanism of nonphotochemical dissipation of excess energy in plants. PMID:10715102
NASA Astrophysics Data System (ADS)
Jin, Guanghao; Yoon, Jin-Hee; Cha, Dongwoo
2008-03-01
We examine the effects of the additional term of the type {\\sim} e^{- \\lambda^{\\prime} N_pN_n} on the recently proposed empirical formula for the lowest excitation energy of the 2+ states in even-even nuclei. This study is motivated by the fact that this term carries the favorable dependence of the valence nucleon numbers dictated by the NpNn scheme. We show explicitly that there is not any improvement in reproducing Ex(2+1) by including the extra NpNn term. However, our study also reveals that the excitation energies Ex(2+1), when calculated by the NpNn term alone (with the mass number A dependent term), are quite comparable to those calculated by the original empirical formula.
Mukherjee, Saikat; Adhikari, Satrajit; Mukhopadhyay, Debasis
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 H{sub 3}{sup +} 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.
NASA Astrophysics Data System (ADS)
Wegner, Franz
1983-12-01
The density of states of two-dimensional electrons in a strong perpendicular magnetic field and white-noise potential is calculated exactly under the provision that only the states of the free electrons in the lowest Landau level are taken into account. It is used that the integral over the coordinates in the plane perpendicular to the magnetic field in a Feynman graph yields the inverse of the number λ of Euler trails through the graph, whereas the weight by which a Feynman graph contributes in this disordered system is λ times that of the corresponding interacting system. Thus the factors λ cancel which allows the reduction of the d dimensional disordered problem to a ( d-2) dimensional φ4 interaction problem. The inverse procedure and the equivalence of disordered harmonic systems with interacting systems of superfields is used to give a mapping of interacting systems with U(1) invariance in d dimensions to interacting systems with UPL(1,1) invariance in ( d+2) dimensions. The partition function of the new systems is unity so that systems with quenched disorder can be treated by averaging exp(- H) without recourse to the replica trick.
NASA Astrophysics Data System (ADS)
Mukherjee, Saikat; Mukhopadhyay, Debasis; Adhikari, Satrajit
2014-11-01
We calculate the adiabatic Potential Energy Surfaces (PESs) and the Non-Adiabatic Coupling Terms (NACTs) for the three lowest singlet states of H_3^+ 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.
Peng, Huo-Lei; Payton, John L.; Protasiewicz, John D.
2009-01-01
Aryl diphosphenes (Ar-P=P-Ar) possess features that may make them useful in photonic devices, including the possibility for photochemical E-Z isomerization. Development of good models guided by computations is hampered by poor correspondence between predicted and experimental UV/vis absorption spectra. An hypothesis that the phenyl twist angle (i.e. PPCC torsion) accounts for this discrepancy is explored, with positive findings. DFT and TDDFT (B3LYP) were applied to the phenyl-P=P-phenyl (Ph-P=P-Ph) model compound over a range of phenyl twist angles, and to the Ph-P=P-Ph cores of two crystallographically characterized diphosphenes: bis-(2,4,6-tBu3C6H2)-diphosphene (Mes*-P=P-Mes*) and bis-(2,6-Mes2C6H3)-diphosphene (Dmp-P=P-Dmp). A shallow PES is observed: the full range of phenyl twist angles is accessible for under 5 kcal/mol. The Kohn-Sham orbitals (KS-MOs) exhibit stabilization and mixing of the two highest energy frontier orbitals – the n+ and π localized primarily on the – P=P– unit. A simple, single-configuration model based upon this symmetry-breaking is shown to be consistent with the major features of the measured UV/vis spectra of several diphosphenes. Detailed evaluation of singlet excitations, transition energies and oscillator strengths with TDDFT showed that the lowest energy transition (S1 ← S0) does not always correspond to the LUMO ← HOMO configuration. Coupling between the phenyl rings and central –P=P– destabilizes the π-π* dominated state. Hence, the S1 is always n+-π* in nature, even with a π-type HOMO. This coupling of the ring and –P=P– π systems engenders complexity in the UV/vis absorption region, and may be the origin of the variety of photobehaviours observed in diphosphenes. PMID:19496568
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)
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). PMID:25217920
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)
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. PMID:22891949
Molecular heat pump for rotational states
Lazarou, C.; Keller, M.; Garraway, B. M.
2010-01-15
In this work, we investigate the theory for three different unidirectional population-transfer schemes in trapped multilevel systems which can be utilized to cool molecular ions. The approach we use exploits the laser-induced coupling between the internal and motional degrees of freedom so that the internal state of a molecule can be mapped onto the motion of that molecule in an external trapping potential. By sympathetically cooling the translational motion back into its ground state, the mapping process can be employed as part of a cooling scheme for molecular rotational levels. This step is achieved through a common mode involving a laser-cooled atom trapped alongside the molecule. For the coherent mapping, we will focus on adiabatic passage techniques which may be expected to provide robust and efficient population transfers. By applying far-detuned chirped adiabatic rapid passage pulses, we are able to achieve an efficiency of better than 98% for realistic parameters and including spontaneous emission. Even though our main focus is on cooling molecular states, the analysis of the different adiabatic methods has general features which can be applied to atomic systems.
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…
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.
Solid State Replacement of Rotating Mirror Cameras
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.
Short Rotation Crops in the United States
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.
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.
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 (3)P+ triplet ground state at strong confinements and the (5)S- quintet ground state at the weak ones, the energy crossing occurring at ω ≈ 0.0240919. PMID:25084902
NASA Astrophysics Data System (ADS)
Nickel, Bernhard; Klemp, Dieter
1993-08-01
In liquid isopentane the lowest triplet (T 1) state of azulene- h8 and azulene- d8 can be populated by triplet energy transfer from phenazine. At low temperatures (≲ 150 K) two delayed luminescences are observed: phosphorescence and E-type delayed S 1→ S 0 fluorescence (EDF) due to thermally activated intersystem crossing (ISC) T 1⇝S 1. At higher temperature (≳ 200 K) the EDF dominates. The temperature dependence of the EDF is in accord with ISC T 1⇝S 1 being the only temperature-dependent triplet decay process. Light-atom out-of-plane bending modes are likely to be the promoting modes. The literature on the lowest triplet state of azulene is reviewed.
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.
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.
NASA Astrophysics Data System (ADS)
Maier, S.; Port, H.
1987-11-01
Photoexcitation spectra of triplet (T1← S0) zero-phonon lines and phonon sidebands in different anthracene electron donor-acceptor (EDA) complex crystals (A-PMDA, A-TCNB, A-TCPA) have been analyzed between 1.3 K and 50 K at high spectral resolution. From the electron-phonon coupling strength at T = 0 K values of the charge-transfer (CT) character in the range between 6% and 10% are calculated. The differences in these values are found to be correlated with the energetic positions of the triplet state, which are explained within the framework of the Mulliken theory.
The rotational spectrum of the NiS radical in the X3Sigma- state.
Yamamoto, Takuya; Tanimoto, Mitsutoshi; Okabayashi, Toshiaki
2007-07-28
The rotational spectrum of the NiS radical in the X(3)Sigma(-) state was observed by employing a source-modulation microwave spectrometer. The NiS radical was generated in a free space cell by a dc glow discharge in H(2)S diluted with Ar. The nickel atoms were supplied by the sputtering reaction from a nickel cathode. Rotational transitions with J = 11-10 to 25-24 were measured in the region between 135 and 314 GHz. Rotational, centrifugal distortion and several fine-structure constants were determined by a least-squares analysis. Other spectroscopic parameters such as dissociation energy, vibrational wavenumber and equilibrium bond length were also derived from the determined molecular constants. Excitation energies of the lowest (3)Pi and (1)Sigma(+) states were estimated from the fine-structure constants, lambda and gamma. PMID:17622409
Hall, Jeremy; Renger, Thomas; Müh, Frank; Picorel, Rafael; Krausz, Elmars
2016-09-01
The identification of low-energy chlorophyll pigments in photosystem II (PSII) is critical to our understanding of the kinetics and mechanism of this important enzyme. We report parallel circular dichroism (CD) and circularly polarized luminescence (CPL) measurements at liquid helium temperatures of the proximal antenna protein CP47. This assembly hosts the lowest-energy chlorophylls in PSII, responsible for the well-known "F695" fluorescence band of thylakoids and PSII core complexes. Our new spectra enable a clear identification of the lowest-energy exciton state of CP47. This state exhibits a small but measurable excitonic delocalization, as predicated by its CD and CPL. Using structure-based simulations incorporating the new spectra, we propose a revised set of site energies for the 16 chlorophylls of CP47. The significant difference from previous analyses is that the lowest-energy pigment is assigned as Chl 612 (alternately numbered Chl 11). The new assignment is readily reconciled with the large number of experimental observations in the literature, while the most common previous assignment for the lowest energy pigment, Chl 627(29), is shown to be inconsistent with CD and CPL results. Chl 612(11) is near the peripheral light-harvesting system in higher plants, in a lumen-exposed region of the thylakoid membrane. The low-energy pigment is also near a recently proposed binding site of the PsbS protein. This result consequently has significant implications for our understanding of the kinetics and regulation of energy transfer in PSII. PMID:27342201
Romero, Elisabet; Mozzo, Milena; van Stokkum, Ivo H.M.; Dekker, Jan P.; van Grondelle, Rienk; Croce, Roberta
2009-01-01
The peripheral light-harvesting complex of photosystem I contains red chlorophylls (Chls) that, unlike the typical antenna Chls, absorb at lower energy than the primary electron donor P700. It has been shown that the red-most absorption band arises from two excitonically coupled Chls, although this interaction alone cannot explain the extreme red-shifted emission (25 nm, ∼480 cm−1 for Lhca4 at 4 K) that the red Chls present. Here, we report the electric field-induced absorption changes (Stark effect) on the Qy region of the Lhca4 complex. Two spectral forms, centered around 690 nm and 710 nm, were necessary to describe the absorption and Stark spectra. The analysis of the lowest energy transition yields a high value for the change in dipole moment, Δμ710nm ≈ 8 Df−1, between the ground and excited states as compared with monomeric, Δμ = 1 D, or dimeric, Δμ = 5 D, Chl a in solution. The high value of the Δμ demonstrates that the origin of the red-shifted emission is the mixing of the lowest exciton state with a charge-transfer state of the dimer. This energetic configuration, an excited state with charge-transfer character, is very favorable for the trapping and dissipation of excitations and could be involved in the photoprotective mechanism(s) of the photosystem I complex. PMID:19254528
Reducing collective quantum state rotation errors with reversible dephasing
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.
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.
Inhibited rotational quenching in oriented ultra-high rotational states of CO2
NASA Astrophysics Data System (ADS)
Toro, Carlos; Liu, Qingnan; Echebiri, Geraldine O.; Mullin, Amy S.
2013-07-01
We demonstrate long-lived rotational orientation of CO2 molecules originally prepared in an optical centrifuge. The optical centrifuge traps molecules in a strong optical field and spins them to high rotational states by angular acceleration of the optical field. In the case of CO2, the optical centrifuge creates ultra-high rotational states with J ≥ 220. Polarisation-dependent, high-resolution transient infrared (IR) absorption was used to measure the spatial orientation of CO2 molecules in the (0000, J = 76) state following the optical centrifuge pulse and subsequent collisional energy transfer. Transient Doppler-broadened line profiles show that CO2 molecules in J = 76 probed with an IR transition dipole parallel to the initial plane of rotation are more plentiful and have higher translational temperatures than molecules with an IR transition dipole perpendicular to this plane. Time-dependent data show that the initial angular momentum orientation persists even after thousands of collisions, indicating that molecules in an optical centrifuge behave as quantum gyroscopes. These observations demonstrate that the optical centrifuge prepares an anisotropic rotational distribution and that molecules in oriented, ultra-high angular momentum states require many more collisions to randomise their orientation than do those in low rotational states.
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.
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.
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.
NASA Astrophysics Data System (ADS)
Nickel, Bernhard; Klemp, Dieter
1993-08-01
The decay rate constant k for the lowest triplet state of azulene (T 1) can be determined from the time dependence of three kinetically different delayed luminescences: (1) delayed S 2 → S 0 fluorescence due to hetero triplet-triplet annihilation T 1+T' 1 ⇝ S 2+S' 0, where T' 1 is the lowest triplet state of a sensitizer; (2) delayed S 2→S 0 fluorescence due to thermally activated homo triplet-triplet annihilation T 1+T 1⇝S 2+S 0; (3) phosphorescence and E-type delayed S 1→S 0 fluorescence. The kinetic and experimental conditions for the reliable determination of k are treated in detail. k has been determined between 130 and 270 K for azulene- h8 and azulene- d8 in isopentane. The temperature dependence of k can be represented by k= k0+ k1 exp(- Ea/ kBT). The values of k0, k1 and Ea are significantly different for azulene- h8 and azulene- d8.
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.
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.
NASA Astrophysics Data System (ADS)
Kawamura, Y.; Nagasawa, T.; Nakai, H.
2001-05-01
We theoretically investigate the internal rotations of the methyl group in methyl-azabenzenes, such as o- and m-methylpyridines, 2-methylpyrazine, 4-methylpyrimidine, 4-methylpyridadine, and 4-methyl-1,2,3-triazine in the ground, excited, and anionic states. The calculated rotational barriers reproduce well the experimental data. Orbital pictures are given for the barrier changes by excitation and electron attachment. An idea of π*-σ* hyperconjugation is applied for a comprehensive interpretation of the barrier changes. A correlation is found between the rotational barriers and the splitting of the lowest and next-lowest unoccupied molecular orbitals.
NASA Astrophysics Data System (ADS)
Mukhopadhyay, Indra
2016-05-01
In this report the spectroscopic results for far infrared Fourier transform spectrum corresponding to the b-type transitions within the lowest lying trans-substrate (e0) have been presented. The calculated matrix elements connecting various K-levels suggest that ΔK = 1 transitions within the trans- subs-state should be quite strong but the transitions between the trans state to the gauche states would quite week (practically non-existent). This was also concluded by previous studies using microwave and millimeter wave regions (Pearson et al., 1982; Millar, 1995). The assignments were confirmed by direct observations at the spectrum and the agreement between the observed and calculated spectrum using precise energy levels reported by Pearson et al. (1982). All the strong RR and some RQ branch lines starting from K = 10 ← 9 through K = 24 ← 23 have been identified. State dependent expansion parameters for all the 15 sub-bands have been presented. These parameters can reproduce the experimental wave numbers within experimental uncertainty. An atlas for about 450 transition lines corresponding to transitions within the e0 torsional-vibrational species has been prepared. To our knowledge this is the first time the high resolution far infra-red spectral region study for ethanol have been performed.
Peláez, Daniel; Sadri, Keyvan; Meyer, Hans-Dieter
2014-02-01
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. PMID:23831046
He, Xiaohu; Lv, Shuangjiang; Hayat, Tasawar; Han, Keli
2016-04-21
Two new potential energy surfaces are established for the ground and first excited electronic states of the LiH2(+) system, which are important for the astrophysics-related H(+) + LiH(+) and H(+) + LiH reactions. The ab initio energy points are calculated using the complete active space self-consistent field and multireference configuration interaction method with aug-cc-pVQZ basis set. At each state, more than 40000 energy points are calculated. The spectroscopic constants of the diatoms and the topographical characters of the new surfaces are examined in detail, showing good agreement with the available literature results. The reaction probabilities, integral and differential cross sections, and rate constants for the H(+) + LiH ⇌ H2(+) + Li reactions are obtained by performing quantum dynamics calculations, and compared with the previous literature results. The reaction mechanisms are discussed in detail. It is shown that the new surfaces can be recommended for the dynamics study of the H(+) + LiH(+) and H(+) + LiH(+) reactions and other research including LiH2(+) based rovibrational spectra and cluster dynamics. PMID:27022663
Uberseder, E.; Rogachev, G. V.; Goldberg, V. Z.; Koshchiy, E.; Roeder, B. T.; Alcorta, M.; Chubarian, G.; Davids, B.; Fu, C.; Hooker, J.; et al
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
Ke, Xian-Sheng; Zhao, Hongmei; Zou, Xiaoran; Ning, Yingying; Cheng, Xin; Su, Hongmei; Zhang, Jun-Long
2015-08-26
Learning nature's approach to modulate photophysical properties of NIR porphyrinoids by fine-tuning β-substituents including the number and position, in a manner similar to naturally occurring chlorophylls, has the potential to circumvent the disadvantages of traditional "extended π-conjugation" strategy such as stability, molecular size, solubility, and undesirable π-π stacking. Here we show that such subtle structural changes in Pt(II) or Pd(II) cis/trans-porphodilactones (termed by cis/trans-Pt/Pd) influence photophysical properties of the lowest triplet excited states including phosphorescence, Stokes shifts, and even photosensitization ability in triplet-triplet annihilation reactions with rubrene. Prominently, the overall upconversion capability (η, η = ε·Φ(UC)) of Pd or Pt trans-complex is 10(4) times higher than that of cis-analogue. Nanosecond time-resolved infrared (TR-IR) spectroscopy experiments showed larger frequency shift of ν(C═O) bands (ca. 10 cm(-1)) of cis-complexes than those of trans-complexes in the triplet excited states. These spectral features, combining with TD-DFT calculations, suggest the strong electronic coupling between the lactone moieties and the main porphyrin chromophores and thus the importance of precisely positioning β-substituents by mimicking chlorophylls, as an alternative to "extended π-conjugation", in designing NIR active porphyrinoids. PMID:26247480
Optical Characterization of Deep-Space Object Rotation States
NASA Astrophysics Data System (ADS)
Hall, D.; Kervin, P.
2014-09-01
Analysis of time-series data can yield remarkably accurate estimates of the frequency of a satellites brightness modulations. These apparent or synodic frequencies can vary in time, differing from the actual rotation rate of the object by an amount that depends on the relative angular motion between the satellite, illuminator, and observer for reflected light measurements (or between the satellite and observer for thermal emission measurements). When detected with sufficient accuracy, such synodic frequency variations can be exploited to characterize an objects rotation state, using an analysis that does not require any a priori knowledge of the objects shape. For instance, this shape-independent analysis method can be used to derive spin-axis orientations and sidereal rotation rates for spinning objects. Remotely determining such rotation parameters can be useful in many circumstances, such as when performing anomaly resolution of satellites that have lost stabilization. Unfortunately, synodic variations cannot be detected by ground-based observers for many deep-space objects due to low rates of relative angular motion. This is especially true for objects in geosynchronous orbit. In these cases, deriving spin-axis orientations can be accomplished using a shape-dependent method that employs a model of the shape and reflectance characteristics of the object. Our analysis indicates that a simple cylinder model can often suffice to characterize rotation states for upper-stage rocket bodies.
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.
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.
NASA Astrophysics Data System (ADS)
Zafra, José Luis; González Cano, Rafael C.; Ruiz Delgado, M. Carmen; Sun, Zhe; Li, Yuan; López Navarrete, Juan T.; Wu, Jishan; Casado, Juan
2014-02-01
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.
Pseudosteady-state mixed convection inside rotating spherical containers
Khodadadi, J.M.; Li, W.; Shi, X.
1999-07-01
A computational study of the pseudosteady-state two-dimensional mixed convection within rotating spherical containers is presented. The computations are based on an iterative, finite-volume numerical procedure using primitive dependent variables, whereby the time-dependent continuity, momentum and energy equations in the spherical coordinate system are solved. Natural convection effect is modeled via the Boussinesq approximation. For a fixed Prandtl number of 4.62, parametric studies were performed by varying the Rayleigh number in order to cover the laminar regime adequately. For a given Rayleigh number, the ratio of Gr/Re{sup 2} was varied between 0.1 and 10. Given a Rayleigh number, the streamline patterns maintain their general shape with a dominant rotating vortex. As the forced convection effect becomes less marked, the streamlines exhibit less pronounced gradients near the surface of the sphere. As the rotational effect become more marked, the extent of the deviation from the limiting case of non-rotating spheres becomes more noticed. However, the bottom of the sphere still remains to be the region with enhanced heat transfer. Given a rotational Reynolds number, the streamline patterns are not affected greatly as the natural convection is promoted, however the temperature gradients near the surface are markedly enhanced. It is noticed that as natural convection effects are promoted, the greater portion of the sphere's surface experiences enhanced heat transfer rates. Given a Rayleigh number, the contours of the azimuthal velocity exhibit a nearly vertical equally-spaced pattern suggesting that solid-body rotation for high rotational Reynolds numbers. However, as the natural convection effects are enhanced, the contours become more slanted. The variation of the mean Nusselt number with the Reynolds and Rayleigh numbers is also quantified.
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
From rotating atomic rings to quantum Hall states
Roncaglia, M.; Rizzi, M.; Dalibard, J.
2011-01-01
Considerable efforts are currently devoted to the preparation of ultracold neutral atoms in the strongly correlated quantum Hall regime. However, the necessary angular momentum is very large and in experiments with rotating traps this means spinning frequencies extremely near to the deconfinement limit; consequently, the required control on parameters turns out to be too stringent. Here we propose instead to follow a dynamic path starting from the gas initially confined in a rotating ring. The large moment of inertia of the ring-shaped fluid facilitates the access to large angular momenta, corresponding to giant vortex states. The trapping potential is then adiabatically transformed into a harmonic confinement, which brings the interacting atomic gas in the desired quantum-Hall regime. We provide numerical evidence that for a broad range of initial angular frequencies, the giant-vortex state is adiabatically connected to the bosonic ν = 1/2 Laughlin state. PMID:22355562
Rotating mirror plasmas in the quest of magnetofluid states
NASA Astrophysics Data System (ADS)
Quevedo, Hernan Javier
The goal of this dissertation is to describe and discuss the first steps taken by the Magneto Bernoulli eXperiment (MBX) to create magnetofluid states in the laboratory using a rotating plasma in an external mirror magnetic field. The terminology magnetofluid has been introduced to characterize a plasma model, based on 2-fluid theory, that treats the flow and the magnetic field in a symmetrical way. Many interesting astrophysical and laboratory problems involve large flows and fall in this category. Based on the set of parameters where MBX should run, we set up the experiment, and added different probes to diagnose the rotating plasma. We have also installed a data acquisition system, and set up an archive system (to store the data) that can be accessed worldwide. Experimental results demonstrate that supersonic flows can be generated with biasing electrodes at the throat of the mirror magnetic field. Alfvenic flows needed for a transition to magnetofluid states could not be reached because the initial plasma density was too low. At low bias (slow rotational speed) the plasma has E x B/B 2 drift rotation and the magnetic fields lines are equipotentials. With a higher bias, we observed large potential drops along the field lines. We also observed an asymmetry in the polarity of the bias which leads to constraints in the control of the sheared plasma flow. We present a model that captures many of these features. In conjunction with experimental efforts we develop a theory for a rotating plasma embedded in an external mirror magnetic field. An analytic solution that involves rigid rotation of the plasma shows important differences between a 2-fluid system and ideal MHD. We find high non equipotential magnetic lines and asymmetry to compare with the experimental results.
A theoretical study of the ground state and lowest excited states of PuO0/+/+2 and PuO20/+/+2
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.
NASA Astrophysics Data System (ADS)
Yannouleas, Constantine; Landman, Uzi
2011-10-01
Recently observed microwave resonances in the spectrum of a two-dimensional electon gas under high magnetic fields in the neighborhood of the fractional filling ν=1/3 were interpreted as signatures of a weakly pinned Wigner solid. Using the rotating-and-vibrating electron-molecule (RVEM) theory [Yannouleas and Landman, Phys. Rev. B10.1103/PhysRevB.66.115315 66, 115315 (2002); Phys. Rev. A10.1103/PhysRevA.81.023609 81, 023609 (2010)], in conjunction with exact diagonalization, a unified microscopic approach is developed for the interplay between liquid fractional-quantum-Hall-effect (FQHE) and Wigner-solid states in the lowest Landau level (LLL) in the neighborhood of ν=1/3. In contrast to more traditional treatments, the RVEM theory utilizes a single class of variational wave functions for the description of both the FQHE liquid and Wigner-solid states, and their coexistence. Liquid characteristics of the FQHE states are associated with the symmetry-conserving rotations and vibrations of the electron molecule. The liquid characteristics, however, coexist with intrinsic correlations that are crystalline in nature, as revealed by the conditional probability distributions. Although the electron densities of the symmetry-conserving LLL states do not exhibit crystalline patterns, the intrinsic crystalline correlations are reflected in the emergence of cusp yrast states in the LLL spectra. These cusp states correspond to fractional fillings in the thermodynamic limit and are the only ones to provide the global ground states of the system. It is shown that away from the exact fractional fillings, weak pinning perturbations (due to weak disorder) may overcome the energy gaps between adjacent global states and generate pinned broken symmetry ground states as a superposition of symmetry-conserving LLL states with different total angular momenta. The electron densities of such mixed states (without good angular momentum quantum numbers) exhibit oscillating patterns that
Rotating states of self-propelling particles in two dimensions
NASA Astrophysics Data System (ADS)
Chen, Hsuan-Yi; Leung, Kwan-Tai
2006-05-01
We present particle-based simulations and a continuum theory for steady rotating flocks formed by self-propelling particles (SPPs) in two-dimensional space. Our models include realistic but simple rules for the self-propelling, drag, and interparticle interactions. Among other coherent structures, in particle-based simulations we find steady rotating flocks when the velocity of the particles lacks long-range alignment. Physical characteristics of the rotating flock are measured and discussed. We construct a phenomenological continuum model and seek steady-state solutions for a rotating flock. We show that the velocity and density profiles become simple in two limits. In the limit of weak alignment, we find that all particles move with the same speed and the density of particles vanishes near the center of the flock due to the divergence of centripetal force. In the limit of strong body force, the density of particles within the flock is uniform and the velocity of the particles close to the center of the flock becomes small.
Rotating states of self-propelling particles in two dimensions.
Chen, Hsuan-Yi; Leung, Kwan-Tai
2006-05-01
We present particle-based simulations and a continuum theory for steady rotating flocks formed by self-propelling particles (SPPs) in two-dimensional space. Our models include realistic but simple rules for the self-propelling, drag, and interparticle interactions. Among other coherent structures, in particle-based simulations we find steady rotating flocks when the velocity of the particles lacks long-range alignment. Physical characteristics of the rotating flock are measured and discussed. We construct a phenomenological continuum model and seek steady-state solutions for a rotating flock. We show that the velocity and density profiles become simple in two limits. In the limit of weak alignment, we find that all particles move with the same speed and the density of particles vanishes near the center of the flock due to the divergence of centripetal force. In the limit of strong body force, the density of particles within the flock is uniform and the velocity of the particles close to the center of the flock becomes small. PMID:16802998
Distribution of xp in some molecular rotational states
NASA Astrophysics Data System (ADS)
Liu, Q. H.
2014-02-01
Developing the analysis of the distribution of the so-called posmom xp to some molecular rotational states for diatomic molecules and spherical cage molecules, we obtain posmometry (introduced recently by Bernard and Gill, 2010 [5]) of the spherical harmonics and demonstrate that it is similar to the momentum distributions of the stationary states for a one-dimensional simple harmonic oscillator. The results are not only potentially experimentally testable but also reflect a fact that the embedding of the two-dimensional spherical surface S2 in three-dimensional flat space R3 is physically self-consistent and appealing.
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
Gutierrez, Fabien; Tedeschi, Christine; Maron, Laurent; Daudey, Jean-Pierre; Poteau, Romuald; Azema, Joëlle; Tisnès, Pierre; Picard, Claude
2004-05-01
In this paper, we evaluate the potential use of theoretical calculations to obtain an energy scale of the lowest ligand-centred triplet excited state in luminescent terbium(III) complexes. In these complexes, non-radiative deactivation of the terbium emitting state via a back-energy transfer process (T1<--Tb(5D4)) is a common quenching process. Consequently the prediction of the energy gap between these two excited states should be useful for programming highly luminescent Tb(III) systems. We report on a strategy based upon experimental and theoretical investigations of the excited state properties of a series of four simple aromatic hydroxamate ligands coordinated to Tb(III) and Gd(III) ions. By using previously reported crystallographic data, the structural and energies properties of these systems were investigated in the ground and first excited triplet states at the density functional theory (DFT) level of calculations. Our theoretical results are consistent with a triplet excited state T1 which is localised on one ligand only and whose the energy level is independent of the lanthanide ion nature (Tb(III), Gd(III)). A good agreement between the calculated adiabatic transition energies and experimental data derived from emission spectra is obtained when a corrective term is considered. These satisfactory results are an indication that this type of modelling can lead to discriminate in terms of the position of the lowest ligand triplet energy level the best antenna among a family of chromophoric compounds. In addition this theoretical approach has provided indications that the difference between the adiabatic transition energies of all the investigated complexes can be mainly explained by metal-ligand electrostatic interactions. The influence of the number of antennae on the quantum yield and the luminescence lifetime is discussed. PMID:15252626
Ground-state rotational constants of 12CH 3D
NASA Astrophysics Data System (ADS)
Chackerian, C.; Guelachvili, G.
1980-12-01
An analysis of ground-state combination differences in the ν2( A1) fundamental band of 12CH 3D ( ν0 = 2200.03896 cm -1) has been made to yield values for the rotational constants B0, D0J, D0JK, H0JJJ, H0JJK, H0JKK, LJJJJ, L0JJJK, and order of magnitude values for L0JJKK and L0JKKK. These constants should be useful in assisting radio searches for this molecule in astrophysical sources. In addition, splittings of A1A2 levels ( J ≥ 17, K = 3) have been measured in both the ground and excited vibrational states of this band.
Lowest eigenvalues of random Hamiltonians
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.
NASA Astrophysics Data System (ADS)
Yoshinaga, N.; Arima, A.; Zhao, Y. M.
2006-01-01
In this report we study the origin of spin-zero ground-state dominance for even-even nuclei in the presence of random two-body interactions. We evaluate the ground-state energy in terms of the energy centroid and the width of the random Hamiltonian. For both fermions and bosons in a single orbital, we obtain excellent agreement between the spin-I ground state probabilities predicted by using our formula and those obtained by diagonalizing the random Hamiltonian.
Muon Spin Rotation Spectroscopy - Utilizing Muons in Solid State Physics
Suter, Andreas
2012-10-17
Over the past decades muon spin rotation techniques (mSR) have established themselves as an invaluable tool to study a variety of static and dynamic phenomena in bulk solid state physics and chemistry. Common to all these approaches is that the muon is utilized as a spin microprobe and/or hydrogen-like probe, implanted in the material under investigation. Recent developments extend the range of application to near surface phenomena, thin film and super-lattice studies. After briefly summarizing the production of so called surface muons used for bulk studies, and discussing the principle differences between pulsed and continuous muon beams, the production of keV-energy muon sources will be discussed. A few topical examples from different active research fields will be presented to demonstrate the power of these techniques.
Rotation state of 495 Eulalia and its implication
NASA Astrophysics Data System (ADS)
Vokrouhlický, D.; Ďurech, J.; Pravec, P.; Oey, J.; Vraštil, J.; Hornoch, K.; Kušnirák, P.; Groom, R.; Warner, B. D.; Bottke, W. F.
2016-01-01
Context. The low-albedo part of the Nysa-Polana-Hertha asteroid complex has recently been found to consist of at least two families. The larger of them has been associated with asteroid 495 Eulalia, hereafter named the Eulalia family. The unstable location of this body very close to Jupiter's 3:1 mean motion resonance (J3/1 resonance) at the periphery of the associated family in the space of proper orbital elements makes this case peculiar. Aims: We consider the possibility that 495 Eulalia was originally positioned farther from the J3/1 resonance when the family formed via a catastrophic impact than it is today. It was then transported to its current orbit by the Yarkovsky thermal forces over hundreds of millions of years. This requires that 495 Eulalia had a prograde rotation state. Methods: We use photometric observations and lightcurve inversion methods to determine the rotation pole of 495 Eulalia. Numerical simulation accounting for perturbations from the Yarkovsky effect then reveals the possible pathways of Eulalia orbital evolution. Results: We find that both of the possible pole solutions are prograde, in accordance with our initial hypothesis. In studying the long-term evolution of Eulalia's spin state, we show that the obliquity can oscillate over a large interval of values yet always remain <90°. We estimate that Eulalia could have migrated by as much as ~0.007 au toward the J3/1 resonance within the past 1 Gyr. Our numerical runs show that it could have originated in the orbital zone well aligned with other family members in proper eccentricity, whichafter it gained its current orbit by chaotic evolution along the J3/1 resonance.
NASA Astrophysics Data System (ADS)
Levrard, B.
2008-02-01
In a recent paper, Wisdom [Wisdom, J., 2008. Icarus, 193, 637-640] derived concise expressions for the rate of tidal dissipation in a synchronously rotating body for arbitrary orbital eccentricity and obliquity. He provided numerical evidence than the derived rate is always larger than in an asymptotic nonsynchronous rotation state at any obliquity and eccentricity. Here, I present a simple mathematical proof of this conclusion and show that this result still holds for any spin-orbit resonance.
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
NASA Astrophysics Data System (ADS)
Goldberg, Vladilen; Rogachev, G. V.; Alcorta, M.; Davids, B.; Hooker, J.; Jayatissa, H.; Koshchiy, E.; Nelson, A.; Roeder, B.; Uberseder, E.; Tribble, R. E.
2014-09-01
About 20 years ago, a group of Hahn-Meitner Institute made precision measurements of a multi nucleon transfer reaction to populate the lowest states in 9He. They found [1,2] a state of 9He(1/2-) at 1.27 +/- 0.10 MeV above the 8He + n threshold with Γ = 0.10 +/- 0.06 MeV. Since then, many groups tried to obtain detailed information on 9He mainly using rare isotope beams. However, the energy resolution and counting statistics was never sufficient to test the data [1,2] (see a review in [3]). Additionally an MSU group [4] found a virtual s-wave state within 0.2 MeV of the 8He + n threshold which they claimed to be the ground state of 9He. The theoretical calculations demonstrate rare unanimity. A variety of approaches including the recent [5] ab initio calculations predict a broad state, approximately ten times broader than given in Refs. [1,2]. So it can be that our understanding of nuclear structure at the border of nuclear stability is seriously deficient. To date, it looks like all straightforward ways to obtain spectroscopic information on 9He were tested. So, we populated T = 5/2 states in 9Li (analogs of 9He) in 8He + p resonance elastic scattering using the TTIK method [5,6]. The measurements were performed using 4 MeV/A 8He beam provided by TRIUMF facilities. The scattering chamber was filled with CH4 gas. The proton recoils were detected by an array of position sensitive proportional counters and silicon detectors. The experimental equipment was tested using 3.5 and 7 MeV/A 12C beams of Cyclotron Institute at TAMU.
Altaf, Adeel; Dutta, Sourav; Lorenz, John; Pérez-Ríos, Jesús; Chen, Yong P; Elliott, D S
2015-03-21
We report the formation of ultracold (7)Li(85)Rb molecules in the a(3)Σ(+) 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(-1) below the (7)Li 2s (2)S1/2 + (85)Rb 5p (2)P1/2 asymptote. In addition, we use REMPI spectroscopy to probe the a(3)Σ(+) state and excited electronic 3(3)Π and 4(3)Σ(+) states and identify a(3)Σ(+) (v″ = 7-13), 3(3)Π (vΠ' = 0-10), and 4(3)Σ(+) (vΣ' = 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. PMID:25796252
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.
NASA Astrophysics Data System (ADS)
Theis, Daniel; Ivanic, Joseph; Windus, Theresa L.; Ruedenberg, Klaus
2016-03-01
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 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 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. More accurate
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 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
Stanke, Monika; Kedziera, Dariusz; Bubin, Sergiy; Adamowicz, Ludwik
2007-05-21
In this work the authors present an approach to calculate the leading-order relativistic corrections for ground and excited states of helium isotopomers. In the calculations they used variational wave functions expanded in terms of explicitly correlated Gaussians obtained without assuming the Born-Oppenheimer approximation. PMID:17523809
NASA Astrophysics Data System (ADS)
Liu, Xiaojun; Zhang, Xiao; Hou, Yanbing; Teng, Feng; Lou, Zhidong
2011-03-01
The ground and excited state properties of DCDPC, particularly designed as a red emitter for organic light emitting diodes applications have been studied by means of density functional theory (DFT) and time-dependent (TD)DFT. The electronic and geometrical structures of DCDPC in acetone, tetrahydrofuran and benzene solvents are reported for the first time. The experimental absorption and fluorescence spectra are reproduced by calculations. By comparison with experimental data, insight on the performance of 10 exchange correlation functionals is also given. M06 in the frame of DFT and TDDFT with a polarizable continuum model and a medium sized basis set emerges as the most effective strategy. Beside the good agreement between the calculational and experimental spectra proving the accuracy of the strategy, the calculations allow further insights into the electronic structure for the family of isophorone-based light emitting materials with D-π-A structure, especially the electronic and geometrical structures for the excited states.
The puzzle of the steady-state rotation of a reverse sprinkler
NASA Astrophysics Data System (ADS)
Rueckner, Wolfgang
2015-04-01
The continuous rotation of the reverse sprinkler has been a puzzle for over two decades. This article presents a series of experiments that demonstrate that a properly designed reverse sprinkler experiences no steady-state torque and does not rotate. Ignoring transients when the flow starts and stops, if any sustained rotation of the reverse sprinkler occurs, it is because a force couple produces a torque accompanied by vortex flow inside the body of the sprinkler. No steady-state rotation occurs if the vortex is suppressed or prevented from forming in the first place. Demonstrative proof is given that an ideal reverse sprinkler does not rotate.
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.
The Determination Of Titan'S Rotational State From Cassini Sar Images
NASA Astrophysics Data System (ADS)
Persi Del Marmo, Paolo; Iess, L.; Picardi, G.; Seu, R.; Bertotti, B.
2007-10-01
SAR images acquired by the spacecraft Cassini in overlapping strips have been used to determine the vectorial angular velocity of Titan. The method entails the tracking of surface landmarks at different times (and mean anomalies), spanning a period from 2004 to 2007. Each image is referenced both in an inertial frame and in the IAU, Titan-centric, body-fixed reference frame. This referencing is quite precise (accuracy of Cassini relative to Titan position smaller than 100 m). The IAU body-fixed frame assumes a spin axis different from the actual one. By correlating the two images of the same surface region, one gets a two-dimensional vector, which retains information about the true spin axis. This vector provides the magnitude and direction of the displacement to be applied to a reference point of each image in order to produce maximum correlation. The correlation results therefore in a new Titan-centric, inertial referencing of the images, R(t1) and R(t2). The spin axis s is then obtained by requiring that [R(t2) - R(t1)] • s = 0 for each overlapping image pairs. Left hand sides cannot be simultaneously zeroed because Titan doesn't move respect to the known polar axis and the real spin axis must be determined by means of a least square procedure. The magnitude of the angular velocity is then derived from the angle and time between two observations. The Titan pole position estimated is consistent with the occupancy of a Cassini state. If Titan were a rigid body in a Cassini state (with an icy crust anchored to the mantle), one could use theoretical arguments to derive the moment of inertia from the obliquity and the second degree gravity field. However, our results suggest that those theoretical arguments cannot be straightforwardly applied to Titan, whose rotational state is more complex than expected.
Myrick, M.L.; Blakley, R.L.; DeArmond, M.K.; Arthur, M.L.
1988-03-02
The 77 K absorption, emission, steady-state excitation photoselection (SSExP), and time-resolved excitation photoselection (TRExP) results are reported for 11 (Ru(L)/sub 3/)(PF/sub 6/)/sub 2/ complexes with 2,2'-diimine ligands (L). The ligands are 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen), 2,2'-bipyrazine (bpz), 2-(2-pyridyl)quinoline (pq), and 2,2'-biquinoline (biq). Complexes of the form (Ru(L)/sub 3/)/sup 2 +/ (L = bpy, phen, bpz, pq, and biq) were examined as well as mixed-ligand complexes of the form (Ru(bpy)/sub n/(L)/sub 3-n/)/sup 2 +/ (n = 1, 2) (L = phen, bpz, and pq). Data are also presented for the monomeric model complex, (Ru(bpy)(py)/sub 4/)/sup 2 +/ (py = pyridine). Data indicate that optical excitation leads to static localization of the optically excited electron. A model is developed that rationalizes the maximum value obtainable in the SSExP data. Solvent effects observed in the TRExP data are explained in terms of relative rates of spin-lattice relaxation associated with different solvents.
NASA Technical Reports Server (NTRS)
Stallcop, J. R.
1971-01-01
Collision-induced vibration-rotation transition probabilities are calculated from a semiclassical three-dimensional model, in which the collision trajectory is determined by the classical motion in the interaction potential that is averaged over the molecular rotational state, and compared with those for which the motion is governed by a spherically averaged potential. For molecules that are in highly excited rotational states, thus dominating the vibrational relaxation rate at high temperature, it is found that the transition probability for rotational state averaging is smaller than that for spherical averaging. For typical collisions, the transition cross section is decreased by a factor of about 1.5 to 2.
Rotationally resolved state-to-state photoelectron study of niobium carbide radical
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.
The Determination Of Titan's Rotational State From Cassini SAR Images
NASA Astrophysics Data System (ADS)
Persi Del Marmo, P.; Iess, L.; Picardi, G.; Seu, R.; Bertotti, B.
2007-12-01
- referenced vectors. Titan's rotational state is therefore more complex than expected. If Titan were a rigid body in a Cassini state (with an icy crust anchored to the mantle), one could use theoretical arguments to derive the moment of inertia from the obliquity and the second degree gravity field. However, the new findings suggest that those theoretical arguments cannot be straightforwardly applied.
Prediction and Control of Slip-Free Rotation States in Sphere Assemblies
NASA Astrophysics Data System (ADS)
Stäger, D. V.; Araújo, N. A. M.; Herrmann, H. J.
2016-06-01
We study fixed assemblies of touching spheres that can individually rotate. From any initial state, sliding friction drives an assembly toward a slip-free rotation state. For bipartite assemblies, which have only even loops, this state has at least four degrees of freedom. For exactly four degrees of freedom, we analytically predict the final state, which we prove to be independent of the strength of sliding friction, from an arbitrary initial one. With a tabletop experiment, we show how to impose any slip-free rotation state by only controlling two spheres, regardless of the total number.
Prediction and Control of Slip-Free Rotation States in Sphere Assemblies.
Stäger, D V; Araújo, N A M; Herrmann, H J
2016-06-24
We study fixed assemblies of touching spheres that can individually rotate. From any initial state, sliding friction drives an assembly toward a slip-free rotation state. For bipartite assemblies, which have only even loops, this state has at least four degrees of freedom. For exactly four degrees of freedom, we analytically predict the final state, which we prove to be independent of the strength of sliding friction, from an arbitrary initial one. With a tabletop experiment, we show how to impose any slip-free rotation state by only controlling two spheres, regardless of the total number. PMID:27391726
Unstable rotational states of string models and width of a hadron
Sharov, G. S.
2009-06-01
Rotational states (planar uniform rotations) of various string hadron models are tested for stability with respect to small disturbances. These models include an open or closed string carrying n massive points (quarks), and their rotational states result in a set of quasilinear Regge trajectories. It is shown that rotations of the linear string baryon model q-q-q and the similar states of the closed string are unstable, because spectra of small disturbances for these states contain complex frequencies, corresponding to exponentially growing modes of disturbances. Rotations of the linear model are unstable for any values of points' masses, but for the closed string we have the threshold effect. This instability is important for describing excited hadrons; in particular, it increases predictions for their width {gamma}. Predicted large values {gamma} for N, {delta} and strange baryons in comparison with experimental data result in unacceptability of the linear string model q-q-q for describing these baryon states.
Impact of the nuclear equation of state on models of rotating neutron stars
Weber, F.; Glendenning, N.K.
1991-06-03
The impact of the nuclear equation of state on the properties of rotating neutron stars from two different sources, stable rotation at the general relativistic Kepler period and rotation at the gravitational radiation-reaction driven instability mode, is analyzed. For this purpose models of rotating neutron stars are constructed in the framework of Einstein's theory of general relativity by applying a refined version of Hartle's perturbative stellar structure equations. The investigation is based on a representative collection of a total of seventeen nuclear equations of state, covering both non-relativistic as well as relativistic ones. 41 refs., 3 figs., 2 tabs.
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.
Vortex distribution in the lowest Landau level
NASA Astrophysics Data System (ADS)
Aftalion, Amandine; Blanc, Xavier; Nier, Francis
2006-01-01
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.
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.
Microwave Spectra of Furazan. III. Rotation Spectra of Vibrationally Excited States
NASA Astrophysics Data System (ADS)
Stiefvater, Otto L.
1990-10-01
The pure rotational spectra of molecules in 21 vibrationally excited states of the heterocyclic compound furazan (C2H2N2O) have been detected and studied by DRM microwave spectroscopy. Rotational parameters are reported for the 12 fundamental levels below 1500 cm-1 , and the contri-butions from 10 vibrational modes to the effective rotational constants and to the inertia defect of furazan are calculated.
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.
Lifetimes of superdeformed rotational states in {sup 36}Ar.
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.
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.
NASA Astrophysics Data System (ADS)
Stiefvater, Otto L.
1990-10-01
The pure rotation spectra of molecules in 25 vibrationally excited states of perdeuterated furazan, C2D2N2O, have been studied by double resonance modulation (DRM) microwave spectroscopy. Twelve of these spectra have been correlated, -on the basis of relative intensity measurements under DRM -, with fundamental vibrations as previously established by IR spectroscopy. Rotational parameters for these 12 fundamental levels are reported, and the contributions to the effective rotational constants and to the inertia defect of the ground state of d2 -furazan have been determined for 10 modes of vibration.
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.
Effects of rotational states on the c /a ratio in solid hydrogens
NASA Astrophysics Data System (ADS)
Strzhemechny, Mikhail A.; Hemley, Russell J.
2015-04-01
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. The approach can be generalized to high pressures.
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
Vander Wal, R.L.; Scott, J.L.; Crim, F.F. )
1991-02-01
The state resolved photodissociation of highly vibrationally excited water molecules using laser induced fluorescence detection of the OH product demonstrates the control that the initially selected state exerts over product state populations. These vibrationally mediated photodissociation experiments, in which one photon prepares a highly vibrationally excited molecule and a second photon dissociates it, determine the role of overall rotations and of O--H stretching vibrations as well as measure the relative cross section for the photodissociation of water. The {ital rotational} {ital state} of the vibrationally excited water molecule governs the rotational state of the OH product of the dissociation, in agreement with {ital ab} {ital initio} calculations and previous measurements on single rotational states excited in the fundamental asymmetric stretching vibration band. The initially selected {ital vibrational} {ital state} of the water molecule determines the vibrational energy disposal in the products, which agrees with a simple qualitative model based on the pattern of the initially selected vibrational wave function. Dissociating vibrational states with similar energies but very different nuclear motions produces dramatically different product vibrational state populations. The vibrational energy initially present in the surviving bond primarily appears as vibrational excitation of the product. Dissociation of the {vert bar}04{r angle}{sup {minus}} state produces no vibrationally excited OH, but dissociation of the {vert bar}13{r angle}{sup {minus}} state produces mostly vibrationally excited products.
NASA Astrophysics Data System (ADS)
Kurosaki, Yuzuru; Takayanagi, Toshiyuki
2003-10-01
Global adiabatic potential energy surfaces (PESs) of the lowest three doublet states (1 A2A', 2 2A', and 1 2A″) for the BrH2 system have been calculated using the multireference configuration interaction (MRCI) method including the Davidson's correction (Q) with the aug-cc-pVTZ basis set. Spin-orbit effects were considered on the basis of the Breit-Pauli Hamiltonian using the MRCI wave functions. The calculated adiabatic energies were fitted to the analytical functional form of many-body expansion. The barrier heights of the H+HBr→H2+Br abstraction and H+H'Br→H'+HBr exchange reactions on the ground-state PES were calculated to be 1.28 and 11.71 kcal mol-1, respectively, both of which are slightly smaller than the values obtained in the previous work [G. C. Lynch, D. G. Truhlar, F. B. Brown, and J.-G. Zhao, J. Phys. Chem. 99, 207 (1995)]. The fits for the 1 2A', 2 2A', and 1 2A″ PESs were successful within an accuracy of 0.1 kcal mol-1 in the important regions of PESs such as the transition states and van der Waals wells. Thermal rate constants for the abstraction and exchange reactions and their isotopic variants were calculated with the fitted 1 2A' PES using the improved canonical variational transition-state theory with the least-action adiabatic ground-state approximation method. The calculated rate constants were found to agree better with experiment than those obtained by Lynch et al.
Rotationally Inelastic Scattering of Quantum-State-Selected ND3 with Ar.
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. PMID:25532415
C60 rotation in the solid state - Dynamics of a faceted spherical top
NASA Astrophysics Data System (ADS)
Johnson, Robert D.; Yannoni, Costantino S.; Dorn, Harry C.; Salem, Jesse R.; Bethune, Donald S.
1992-03-01
The C-13 NMR technique is presently used to ascertain the solid-state rotational dynamics of C60. The 283 K molecular reorientation correlation time tau, at 9.1 picosecs, implies a rotational-diffusion constant of 1.8 x 10 exp 10/sec; this is only three times longer than the calculated tau value for free rotation, and is shorter than the value measured for C60 in solution. Below 260 K, a second phase with much longer reorientation time is noted. In both phases, tau exhibits Arrhenius behavior. These results are noted to parallel those established for adamantane.
Jiang, Xing; Rodríguez-Molina, Braulio; Nazarian, Narega; Garcia-Garibay, Miguel A
2014-06-25
We report the design and dynamics of a solid-state molecular rotor with a large triptycene rotator. With a cross-section and surface area that are 2 and 3 times larger than those of the phenylene rotators previously studied in the solid state, it is expected that van der Waals forces and steric hindrance will render the motion of the larger triptycene more difficult. To address this challenge, we used a rigid and shape-persistent stator in a dendritic structure that reaches ca. 3.6 nm in length. Using variable-temperature solid-state (2)H NMR spectroscopy, we determined a symmetric three-fold rotational potential with a barrier of 10.2 kcal/mol and a pre-exponential factor of 1.1 × 10(10) s(-1), which correspond to ca. 4600 Brownian jumps per second in the solid state at 300 K. PMID:24911467
On the internal rotations in p-cresol in its ground and first electronically excited states
NASA Astrophysics Data System (ADS)
Hellweg, Arnim; Hättig, Christof
2007-07-01
The overall rotation and internal rotation of p-cresol (4-methyl-phenol) has been studied by comparison of the microwave spectrum with accurate ab initio calculations using the principal axis method in the electronic ground state. Both internal rotations, the torsions of the methyl and the hydroxyl groups relative to the aromatic ring, have been investigated. The internal rotation of the hydroxyl group can be approximately described as the motion of a symmetrical rotor on an asymmetric frame. For the methyl group it has been found that the potential barrier hindering its internal rotation is very small with the first two nonvanishing Fourier coefficients of the potential V3 and V6 in the same order of magnitude. Different splittings of b-type transitions for the A and E species of the methyl torsion indicate a top-top interaction between both internal rotors through the benzene ring. An effective coupling potential for the top-top interaction could be estimated. The hindering barriers of the hydroxyl and methyl rotation have been calculated using second-order Møller-Plesset perturbation theory and the approximate coupled-cluster singles-and-doubles model (CC2) in the ground state and using CC2 and the algebraic diagrammatic construction through second order in the first electronically excited state. The results are in excellent agreement with the experimental values.
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.
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.
NASA Astrophysics Data System (ADS)
Natterer, Fabian Donat; Patthey, François; Brune, Harald
2014-03-01
The appeal of inelastic electron tunneling spectroscopy with the scanning tunneling microscope (STM) stems from its unmatched spatial resolution and the ability to measure the magnetic, electronic and vibrational properties of individual atoms and molecules. Rotational excitations of molecules could provide additional information of surface processes but have hitherto remained elusive. Here we demonstrate rotational excitation spectroscopy (RES) with the STM for hydrogen and its isotopes on graphene and hexagonal boron nitride. Since the Pauli principle imposes restrictions on the allowed rotational levels J for molecules with identical nuclei, a certain alignment of the nuclear spins entails a specific set of rotational levels. Conversely, measuring the rotational levels allows characterizing the molecular nuclear spin state. We measured excitation energies at 44 meV and 21 meV, corresponding to rotational transitions J = 0 --> 2 for hydrogen and deuterium. We thereby identify the nuclear spin isomers para-H2 and ortho-D2. For HD, we observe J = 0 --> 1 and J = 0 --> 2 transitions, as expected for heteronuclear diatomics. Our measurements demonstrate the potential of STM-RES in the study of nuclear spin states with unprecedented spatial resolution. We acknowledge funding from the Swiss National Science Foundation under Projects No. 140479 and No. 148891.
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.
2016-08-01
Knowing the value of the maximum mass of a differentially rotating relativistic star is a key-step toward 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 article, we study the effects of differential rotation and of the equation of state on the maximum mass of rotating neutron stars modeled as relativistic polytropes with various adiabatic indices. Calculations are performed using a highly accurate numerical code, based on a multi-domain 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 article (Ansorg et al. 2009). 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.
Rotational Spectroscopy on Ultracold 23 Na40 K Ground State Molecules
NASA Astrophysics Data System (ADS)
Will, Sebastian; Park, Jee Woo; Yan, Zoe; Loh, Huanqian; Zwierlein, Martin
2016-05-01
Ultracold molecules with controllable dipolar long-range interactions will open up new routes for quantum simulation and the creation of novel states of matter. In particular, the molecules' rich internal degrees of freedom allow for versatile control of intermolecular interactions by applying static electric and microwave fields. Starting from an ultracold, spin-polarized ensemble of trapped fermionic 23 Na40 K molecules in the absolute ground state, we perform microwave spectroscopy on the first rotationally excited state for a range of magnetic and electric fields. Extracting the rotational and hyperfine coupling constants, we comprehensively understand the observed spectra. Following the coherent transfer of the entire ensemble of chemically stable 23 Na40 K molecules to the first rotationally excited state, we observe a lifetime of more than 3 sec, comparable to the lifetime in the rovibrational ground state. The collisional stability of excited rotational states opens up intriguing prospects for the control of intermolecular van-der-Waals interactions via electric fields.
Gaussian potentials facilitate access to quantum Hall states in rotating Bose gases.
Morris, Alexis G; Feder, David L
2007-12-14
Through exact numerical diagonalization for small numbers of atoms, we show that it is possible to access quantum Hall states in harmonically confined Bose gases at rotation frequencies well below the centrifugal limit by applying a repulsive Gaussian potential at the trap center. The main idea is to reduce or eliminate the effective trapping frequency in regions where the particle density is appreciable. The critical rotation frequency required to obtain the bosonic Laughlin state can be fixed at an experimentally accessible value by choosing an applied Gaussian whose amplitude increases linearly with the number of atoms while its width increases as the square root. PMID:18233424
NASA Astrophysics Data System (ADS)
Zubov, A. S.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.
2011-10-01
Using the statistical and quantum diffusion approaches, we study the population of ground-state rotational bands of superheavy nuclei produced in the fusion-evaporation reactions 208Pb(48Ca,2n)254No, 206Pb(48Ca,2n)252No, and 204Hg(48Ca,2n)250Fm. By describing the relative intensities of E2 transitions between the rotational states, the entry spin distributions of residual nuclei, and the excitation functions for these reactions, the dependence of fission barriers of shell-stabilized nuclei on angular momentum is investigated.
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…
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
Liu, Jinjun; Miller, Terry A
2014-12-26
The rotational structure of the previously observed B̃(2)A' ← X̃(2)A″ and B̃(2)A' ← Ã(2)A' laser-induced fluorescence spectra of jet-cooled cyclohexoxy radical (c-C6H11O) [ Zu, L.; Liu, J.; Tarczay, G.; Dupré, P; Miller, T. A. Jet-cooled laser spectroscopy of the cyclohexoxy radical. J. Chem. Phys. 2004 , 120 , 10579 ] has been analyzed and simulated using a spectroscopic model that includes the coupling between the nearly degenerate X̃ and Ã states separated by ΔE. The rotational and fine structure of these two states is reproduced by a 2-fold model using one set of molecular constants including rotational constants, spin-rotation constants (ε's), the Coriolis constant (Aζt), the quenched spin-orbit constant (aζed), and the vibronic energy separation between the two states (ΔE0). The energy level structure of both states can also be reproduced using an isolated-state asymmetric top model with rotational constants and effective spin-rotation constants (ε's) and without involving Coriolis and spin-orbit constants. However, the spin-orbit interaction introduces transitions that have no intensity using the isolated-state model but appear in the observed spectra. The line intensities are well simulated using the 2-fold model with an out-of-plane (b-) transition dipole moment for the B̃ ← X̃ transitions and in-plane (a and c) transition dipole moment for the B̃ ← Ã transitions, requiring the symmetry for the X̃ (Ã) state to be A″ (A'), which is consistent with a previous determination and opposite to that of isopropoxy, the smallest secondary alkoxy radical. The experimentally determined Ã-X̃ separation and the energy level ordering of these two states with different (A' and A″) symmetries are consistent with quantum chemical calculations. The 2-fold model also enables the independent determination of the two contributions to the Ã-X̃ separation: the relativistic spin-orbit interaction (magnetic effect) and the nonrelativistic
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.
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.
Hindered and modulated rotational states and spectra of adsorbed diatomic molecules
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.}
ROTATION STATE OF COMET 103P/HARTLEY 2 FROM RADIO SPECTROSCOPY AT 1 mm
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.
Infrared spectroscopy of molecular ions in selected rotational and spin-orbit states.
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 C2H2 (+) in selected rotational levels of the (2)Πu,3/2 and (2)Πu,1/2 spin-orbit components of the vibronic ground state. PMID:27394102
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.
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).
NASA Astrophysics Data System (ADS)
Lattanzi, F.; di Lauro, C.; Horneman, V.-M.
The lowest infrared active perpendicular fundamental ν9 of disilane has been analysed on a Fourier transform spectrum between 320 and 430 cm-1, at the spectral resolution of 0.0012 cm-1. The rotation-torsion structure of this band is affected by x,y Coriolis interactions with excited torsional levels of the vibrational ground state, correlating with components of 3ν4 and 4ν4 in the high barrier limit. The interaction of ν9 and 4ν4, forbidden in the D3d symmetry limit, is allowed between components of E torsional symmetry under the G36(EM) extended molecular group, because of the large amplitude of the internal rotation motion. We could determine the values of the main vibration-rotation-torsion parameters of ν9, interaction parameters, and the vibrational wavenumbers of the four torsional components of 3ν4 and of the E3d component of 4ν4. The intrinsic torsional splitting of ν9 is found to be smaller than in the ground vibrational state by 0.0066 cm-1, in good agreement with our theoretical predictions. The possibility of observing the effects of D3d-forbidden interactions in the spectra of ethane-like molecules is also discussed.
Short rotation woody crops: Using agroforestry technology for energy in the United States
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.
Short rotation woody crops: Using agroforestry technology for energy in the United States
Wright, L.L.; Ranney, J.W.
1991-12-31
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.
Hindered rotational physisorption states of H2 on Ag(111) surfaces.
Kunisada, Y; Kasai, H
2015-07-15
We have investigated the physisorption states of H2 on Ag(111) surfaces. To clarify the accurate adsorption properties of H2 on Ag(111), we performed first-principles calculations based on spin-polarized density functional theory (DFT) with the semiempirical DFT-D2 method and the newly-developed exchange functional with the non-local correlation functional vdW-DF2 (rev-vdW-DF2). We constructed exhaustive potential energy surfaces, and revealed that non-negligible out-of-plane potential anisotropy with a perpendicular orientation preference exists even for H2 physisorption on planar Ag(111), as predicted by previous results of resonance-enhanced multiphoton ionization spectroscopy and temperature-programmed desorption experiments. Therefore, the molecular rotational ground states of ortho-H2 split into two energy levels in the anisotropic potential. The obtained adsorption energy and the number of bound states, including the zero-point energies and the rotational energy shift, agree with diffractive and rotationally mediated selective adsorption scattering resonance measurements. The origin of the potential anisotropy on Ag(111) is a combination of the London dispersion interaction and the virtual transition of the metal electron to the unoccupied molecular state. PMID:26151425
An approximate solution to the stress and deformation states of functionally graded rotating disks
NASA Astrophysics Data System (ADS)
Sondhi, Lakshman; Sanyal, Shubhashis; Saha, Kashi Nath; Bhowmick, Shubhankar
2016-07-01
The present work employs variational principle to investigate the stress and deformation states and estimate the limit angular speed of functionally graded high-speed rotating annular disks of constant thickness. Assuming a series approximation following Galerkin's principle, the solution of the governing equation is obtained. In the present study, elasticity modulus and density of the disk material are taken as power function of radius with the gradient parameter ranging between 0.0 and 1.0. Results obtained from numerical solutions are validated with benchmark results and are found to be in good agreement. The results are reported in dimensional form and presented graphically. The results provide a substantial insight in understanding the behavior of FGM rotating disks with constant thickness and different gradient parameter. Furthermore, the stress and deformation state of the disk at constant angular speed and limit angular speed is investigated to explain the existence of optimum gradient parameters.
Symmetry of extremely floppy molecules: Molecular states beyond rotation-vibration separation.
Schmiedt, Hanno; Schlemmer, Stephan; Jensen, Per
2015-10-21
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 (CH5(+)) [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
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
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
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.
C60 rotation in the solid state: dynamics of a faceted spherical top.
Johnson, R D; Yannoni, C S; Dorn, H C; Salem, J R; Bethune, D S
1992-03-01
The rotational dynamics of C(60) in the solid state have been investigated with carbon-13 nuclear magnetic resonance ((13)C NMR). The relaxation rate due to chemical shift anisotropy (1/9T1(CSA)(1)) was precisely measured from the magnetic field dependence of T(1), allowing the molecular reorientational correlation time, tau, to be determined. At 283 kelvin, tau = 9.1 picoseconds; with the assumption of diffusional reorientation this implies a rotational diffusion constant D = 1.8 x 10(10) per second. This reorientation time is only three times as long as the calculated tau for free rotation and is shorter than the value measured for C(60) in solution (15.5 picoseconds). Below 260 kelvin a second phase with a much longer reorientation time was observed, consistent with recent reports of an orientational phase transition in solid C(60). In both phases tau showed Arrhenius behavior, with apparent activation energies of 1.4 and 4.2 kilocalories per mole for the high-temperature (rotator) and low-temperature (ratchet) phases, respectively. The results parallel those found for adamantane. PMID:17816831
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 32S16O3 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 6-fold rotational energy clusters at high rotational excitation are investigated. The SO3 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 100-250. 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.
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.
Rotation State of Comet 103P/Hartley 2 from Radio Spectroscopy at 1 mm
NASA Astrophysics Data System (ADS)
Drahus, Michał; Jewitt, David; Guilbert-Lepoutre, Aurélie; Waniak, Wacław; Hoge, James; Lis, Dariusz C.; Yoshida, Hiroshige; Peng, Ruisheng; Sievers, Albrecht
2011-06-01
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-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. Based on observations carried out with the IRAM 30 m, JCMT 15 m, and CSO 10.4 m telescopes. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). JCMT is operated by Joint Astronomy Centre and supported by STFC (UK), NRC (Canada), and NWO (Netherlands). CSO is operated by Caltech and supported through NSF grant AST-0540882 (USA).
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)
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.
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.
Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state.
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
Terahertz spectroscopy on Faraday and Kerr rotations in a quantum anomalous Hall state
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
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.
NASA Astrophysics Data System (ADS)
Zhao, Meishan; Mladenovic, Mirjana; Truhlar, Donald G.; Schwenke, David W.; Sharafeddin, Omar
1989-11-01
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.
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.
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.
State-to-state cross-sections for rotationally inelastic collision of LiH with Ne
NASA Astrophysics Data System (ADS)
Feng, Eryin; Huang, Wuyin; Cui, Zhifeng; Zhang, Weijun
2004-08-01
The close coupling calculation of rotationally inelastic collision of Ne with LiH is first performed by employing a recently computed ab initio potential energy surface [Chem. Phys. Lett. 327 (2000) 305]. State-to-state differential, partial and integral cross-sections are calculated. Differential cross-sections show the feature of forward scattering for low Δ j inelastic transitions and backward scattering for high Δ j transitions. Two maxima exist in the curve of partial cross-sections and they are originated from different mechanism. The dependence of the integral cross-sections on j' for initial states j=0,1 displays a pronounced oscillatory structure rather than a monotonic one, and dependence on low collision energy presents resonance feature. These features are related to the anisotropic interaction potential.
Fine structure of alpha decay to rotational states of heavy nuclei
Wang, Y. Z.; Dong, J. M.; Peng, B. B.; Zhang, H. F.
2010-06-15
To gain a better insight into alpha-decay fine structure, we calculate the relative intensities of alpha decay to 2{sup +} and 4{sup +} rotational states in the framework of the generalized liquid drop model (GLDM) and improved Royer's formula. The calculated relative intensities of alpha decay to 2{sup +} states are in good agreement with the experimental data. For the relative intensities of alpha decay to 4{sup +} states, a good agreement with experimental data is achieved for Th and U isotopes. The formula we obtain is useful for the analysis of experimental data of alpha-decay fine structure. In addition, some predicted relative intensities which are still not measured are provided for future experiments.
Ground and Low-Lying Collective States of Rotating Three-Boson System
NASA Astrophysics Data System (ADS)
Imran, Mohd.; Ahsan, M. A. H.
2016-04-01
The ground and low-lying collective states of a rotating system of N = 3 bosons harmonically confined in quasi-two-dimension and interacting via repulsive finite-range Gaussian potential is studied in weakly to moderately interacting regime. The N-body Hamiltonian matrix is diagonalized in subspaces of quantized total angular momenta 0 ≥ L ≥ 4N to obtain the ground and low-lying eigenstates. Our numerical results show that breathing modes with N-body eigenenergy spacing of 2ħω⊥, known to exist in strictly 2D system with zero-range (δ-function) interaction potential, may as well exist in quasi-2D system with finite-range Gaussian interaction potential. To gain an insight into the many-body states, the von Neumann entropy is calculated as a measure of quantum correlation and the conditional probability distribution is analyzed for the internal structure of the eigenstates. In the rapidly rotating regime the ground state in angular momentum subspaces L = (q/2)N (N ‑ 1) with q = 2, 4 is found to exhibit the anticorrelation structure suggesting that it may variationally be described by a Bose-Laughlin like state. We further observe that the first breathing mode exhibits features similar to the Bose-Laughlin state in having eigenenergy, von Neumann entropy and internal structure independent of interaction for the three-boson system considered here. On the contrary, for eigenstates lying between the Bose-Laughlin like ground state and the first breathing mode, values of eigenenergy, von Neumann entropy and internal structure are found to vary with interaction.
NASA Astrophysics Data System (ADS)
Wang, Xin; Tan, Ren-Bing; Du, Zhi-Jing; Zhao, Wen-Yu; Zhang, Xiao-Fei; Zhang, Shou-Gang
2014-07-01
Motivated by recent experimental realization of synthetic spin—orbit coupling in neutral quantum gases, we consider the quasi-two-dimensional rotating two-component Bose—Einstein condensates with anisotropic Rashba spin—orbit coupling subject to concentrically coupled annular potential. For experimentally feasible parameters, the rotating condensate exhibits a variety of rich ground state structures by varying the strengths of the spin—orbit coupling and rotational frequency. Moreover, the phase transitions between different ground state phases induced by the anisotropic spin—orbit coupling are obviously different from the isotropic one.
NASA Technical Reports Server (NTRS)
Abel, Bernd; Coy, Stephen L.; Klaassen, Jody J.; Steinfeld, Jeffrey I.
1992-01-01
The state-resolved rotational (R-R, R-T) energy transfer in (N-14)H3 (for NH3-NH3 and NH3-Ar collisions) was studied using an IR double-resonance laser spectroscopic technique. Measurements of both the total rate of depopulation by collisions, and the rates of transfer into specific final rovibrational states (v,J,K) were performed using time-resolved tunable diode laser absorption spectroscopy. A kinetic master-equation analysis of time-resolved level populatons was carried out, yielding state-to-state rate constants and propensity rules for NH3-NH3 and NH3-Ar collisions.
Hydrodynamics on the lowest Landau level
NASA Astrophysics Data System (ADS)
Geracie, Michael; Son, Dam Thanh
2015-06-01
Using the recently developed approach to quantum Hall physics based on Newton-Cartan geometry, we consider the hydrodynamics of an interacting system on the lowest Landau level. We rephrase the non-relativistic fluid equations of motion in a manner that manifests the spacetime diffeomorphism invariance of the underlying theory. In the massless (or lowest Landau level) limit, the fluid obeys a force-free constraint which fixes the charge current. An entropy current analysis further constrains the energy response, determining four transverse response functions in terms of only two: an energy magnetization and a thermal Hall conductivity. Kubo formulas are presented for all transport coefficients and constraints from Weyl invariance derived. We also present a number of Středa-type formulas for the equilibrium response to external electric, magnetic and gravitational fields.
Generalized Frequency Domain State-Space Models for Analyzing Flexible Rotating Spacecraft
NASA Astrophysics Data System (ADS)
Turner, James D.; Elgohary, Tarek A.
2012-06-01
The mathematical model for a flexible spacecraft that is rotating about a single axis rotation is described by coupled rigid and flexible body degrees-of-freedom, where the equations of motion are modeled by integro-partial differential equations. Beam-like structures are often useful for analyzing boom-like flexible appendages. The equations of motion are analyzed by introducing generalized Fourier series that transform the governing equations into a system of ordinary differential equations. Though technically straightforward, two problems arise with this approach: (1) the model is frequency-truncated because a finite number of series terms are retained in the model, and (2) computationally intense matrix-valued transfer function calculations are required for understanding the frequency domain behavior of the system. Both of these problems are resolved by: (1) computing the Laplace transform of the governing integro-partial differential equation of motion; and (2) introducing a generalized state space (consisting of the deformational coordinate and three spatial partial derivatives, as well as single and double spatial integrals of the deformational coordinate). The resulting math model is cast in the form of a linear state-space differential equation that is solved in terms of a matrix exponential and convolution integral. The structural boundary conditions defined by Hamilton's principle are enforced on the closed-form solution for the generalized state space. The generalized state space model is then manipulated to provide analytic scalar transfer function models for original integro-partial differential system dynamics. Symbolic methods are used to obtain closed-form eigen decomposition- based solutions for the matrix exponential/convolution integral algorithm. Numerical results are presented that compare the classical series based approach with the generalized state space approach for computing representative spacecraft transfer function models.
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.
NASA Astrophysics Data System (ADS)
Cotti, Gina; Linnartz, Harold; Meerts, W. Leo; van der Avoird, Ad; Olthof, Edgar H. T.
1996-03-01
In this paper we present Stark measurements on the G:K=-1 vibration-rotation-tunneling (VRT) transition, band origin 747.2 GHz, of the ammonia dimer. The observed splitting pattern and selection rules can be explained by considering the G36 and G144 symmetries of the inversion states involved, and almost complete mixing of these states by the applied electric field. The absolute values of the electric dipole moments of the ground and excited state are determined to be 0.763(15) and 0.365(10) D, respectively. From the theoretical analysis and the observed selection rules it is possible to establish that the dipole moments of the two interchange states must have opposite sign. The theoretical calculations are in good agreement with the experimental results: The calculated dipole moments are -0.74 D for the lower and +0.35 D for the higher state. Our results, in combination with the earlier dipole measurements on the G:K=0 ground state and the G:K=1 transition with band origin 486.8 GHz, confirm that the ammonia dimer is highly nonrigid. Its relatively small and strongly K-dependent dipole moment, which changes sign upon far-infrared excitation, originates from the difference in dynamical behavior of ortho and para NH3.
Raman analysis of bond conformations in the rotator state and premelting of normal alkanes.
Kotula, Anthony P; Walker, Angela R Hight; Migler, Kalman B
2016-06-14
We perform Raman spectroscopic measurements on normal alkanes (CnH2n+2) to quantify the n dependence of the conformational disorder that occurs below the melt temperature. We employ a three-state spectral analysis method originally developed for semi-crystalline polyethylene that posits crystalline, amorphous, and non-crystalline consecutive trans (NCCT) conformations to extract their respective mass fractions. For the alkanes studied that melt via a rotator phase (21 ≤n≤ 37), we find that conformational disorder can be quantified by the loss of NCCT mass fraction, which systematically decreases with increasing chain length. For those that melt directly via the crystal phase (n≥ 40), we observe NCCT conformational mass fractions that are independent of chain length but whose disordered mass fraction increases with length. These complement prior IR measurements which measure disorder via gauche conformations, but have not been able to measure the mass fraction of this disorder as a function of n. An interesting feature of the three-state analysis when applied to alkanes is that the measured fraction of disordered chain conformations in the rotator phase of (10 to 30)% greatly exceeds the mass fraction of gauche bonds (1 to 7)% as measured from IR; we reconcile this difference through DFT calculations. PMID:27174157
Rotational state distributions from vibrational autoionization of H_{2} revisited
Pratt, Stephen T.; McCormack, E. F.; Dehmer, Joseph L.; Dehmer, Patricia M.
1990-01-01
Photoelectron spectra of vibrationally autoionized (X ²Σ⁺_{g})np, v=1,2 Rydberg states of H_{2} were obtained by using an optical--optical double-resonance technique. The spectra were obtained by using a hemispherical electrostatic electron energy analyzer that had sufficient resolution to determine the rotational state distributions of the H⁺_{2} ions. The ionization process occurred in a magnetic and electric field-free region. All of the results are consistent with the assumptions that the photoelectrons are ejected as p waves and that spin effects are negligible. This is in sharp contrast to our earlier results obtained by using a magnetic bottle electron spectrometer, in which the ionization process occurred in a 0.5--1.0 T magnetic field [J. L. Dehmer et al., J. Chem. Phys. 90, 6243 (1989)]. It is concluded that the magnetic field can significantly modify the rotational distributions observed for vibrational autoionization. The implications of this conclusion are discussed, with particular attention to other experiments performed with the magnetic bottle spectrometer.
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.
Rotational isomerism and physical properties of long-chain molecules in solid states
NASA Astrophysics Data System (ADS)
Kobayashi, M.
1985-01-01
Rotational isomerism occurring in solid state of organic long-chain compounds, including synthetic linear polymers, have been concerned in connection with the macroscopic physical properties of bulk materials. The conformational order in the non-crystalline part of polyethylene has been investigated by Raman spectra, and related to the elastic behaviors of bulk samples. In the solid-state phase transition induced by mechanical forces of poly(butylene terephthalate) the macroscopic strain has been related directly to the conformational conversion of the molecules. Concerning the piezoelectric and pyroelectric activities of poly(vinylidene fluoride), polymorphism, phase transition, and structural change on the poling process have been investigated. A ferroelectric-paraelectric phase transition has been found for a series of copolymers of vinylidene fluoride and trifluoroethylene. On the phase transition a great change in molecular conformation is accompanied with the scrambling of the dipolar orientation. This is the characteristic of polymer ferroelectrics in which the dipolar units are linked with each other by covalent bonds in a molecular chain. Spectroscopic evidences are presented indicating that the thermodynamic stability of polymorphs of n-fatty acids is closely related to the rotational isomerism occurring in the carboxyl groups.
NASA Astrophysics Data System (ADS)
Ware, John Matthew
The problem of a vibrating-rotating polyatomic molecule is treated, with emphasis given to the case of molecules with C(,3V) sym- metry. It is shown that several of the gross features of the rotational spectra of polyatomic molecules in excited vibrational states can be predicted by group theoretical considerations. Expressions for the rotational transition frequencies of molecules of C(,3V) symmetry in the ground vibrational state, singly excited degenerate vibrational states, and doubly excited degenerate vibrational states are given. The deri- vation of these expressions by fourth order perturbation theory as given by Amat, Nielsen, and Tarrago is discussed. The ground and V(,10) = 1 rotational spectra of propyne have been investigated in the 17 to 70 GHz, and 17 to 53 GHz regions, respec- tively, and compared with predictions based on higher frequency measurements. The V(,9) = 1 and V(,10) = 2 rotational spectra of propyne have been investigated and assigned for the first time. A perturbation of the V(,9) = 1 rotational spectra for K = -L has been discovered and discussed. Methods of assignment for excited vibrational state spectra are discussed in detail. The methods of assignment given here allow the analysis of spectra where only a relatively small number of experi- mental points are available. A discrepancy has been found in the interpretation of recently reported infrared results on the rotational spectra of propyne in the V(,10) = 1, 2, 3, and 4 vibrational states. The constants of anharmoni- city which describe the change of the rotational constant, B, with the level of excitation of the V(,10) vibrational mode are rederived from microwave data. It is shown that microwave measurements increase the accuracy of one of these constants by over an order of magnitude.
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.
Is rotating between static and dynamic work beneficial for our fatigue state?
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. PMID:27101392
NASA Astrophysics Data System (ADS)
Zheng, Jing-Jing; Ulenikov, O. N.; Bekhtereva, E. S.; Ding, Yun; He, Sheng-Gui; Hu, Shui-Ming; Wang, Xiang-Huai; Zhu, Qing-Shi
2001-09-01
The high-resolution Fourier transform spectra of the DOCl molecule were recorded and analyzed in the region of the ν1 and 2ν2 bands. Transitions belonging to the ν1 and 2ν2 bands were assigned up to Jmax=55 and 46, respectively. The sets of spectroscopic parameters of the (100) and (020) vibrational states obtained from the fit reproduce their energies derived from the experimental data with accuracies close to experimental uncertainties.
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
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.
Line strengths of rovibrational and rotational transitions within the X^3Σ {^-} ground state of NH
NASA Astrophysics Data System (ADS)
Brooke, James S. A.; Bernath, Peter F.; Western, Colin M.; van Hemert, Marc C.; Groenenboom, Gerrit C.
2014-08-01
A new line list for rovibrational and rotational transitions, including fine structure, within the NH X^3Σ {^-} ground state has been created. It contains line intensities in the form of Einstein A and f-values, for all possible bands up to v' = 6, and for J up to between 25 and 44. The intensities are based on a new dipole moment function (DMF), which has been calculated using the internally contracted multi-reference configuration interaction method with an aug-cc-pV6Z basis set. The programs RKR1, LEVEL, and PGOPHER were used to calculate line positions and intensities using the most recent spectroscopic line position observations and the new DMF, including the rotational dependence on the matrix elements. The Hund's case (b) matrix elements from the LEVEL output (available as Supplement 1 of the supplementary material) have been transformed to the case (a) form required by PGOPHER. New relative intensities for the (1,0) band have been measured, and the calculated and observed Herman-Wallis effects are compared, showing good agreement. The line list (see Supplement 5 of the supplementary material) will be useful for the study of NH in astronomy, cold and ultracold molecular systems, and in the nitrogen chemistry of combustion.
Line strengths of rovibrational and rotational transitions in the X2 Π ground state of OH
NASA Astrophysics Data System (ADS)
Brooke, James S. A.; Bernath, Peter F.; Western, Colin M.; Sneden, Christopher; Afşar, Melike; Li, Gang; Gordon, Iouli E.
2016-01-01
A new line list including positions and absolute transition strengths (in the form of Einstein A values and oscillator strengths) has been produced for the OH ground X2 Π state rovibrational (Meinel system) and pure rotational transitions. All possible transitions are included with v‧ and v ″ up to 13, and J up to between 9.5 and 59.5, depending on the band. An updated fit to determine molecular constants has been performed, which includes some new rotational data and a simultaneous fitting of all molecular constants. The absolute transition strengths are based on a new dipole moment function, which is a combination of two high level ab initio calculations. The calculations show good agreement with an experimental v = 1 lifetime, experimental μv values, and Δv=2 line intensity ratios from an observed spectrum. To achieve this good agreement, an alteration in the method of converting matrix elements from Hund's case (b) to (a) was made. Partitions sums have been calculated using the new energy levels, for the temperature range 5-6000 K, which extends the previously available (in HITRAN) 70-3000 K range. The resulting absolute transition strengths have been used to calculate O abundances in the Sun, Arcturus, and two red giants in the Galactic open and globular clusters M67 and M71. Literature data based mainly on [O I] lines are available for the Sun and Arcturus, and excellent agreement is found.
D.R. Farley, D.P. Ludberg and S.A. Cohen
2010-09-21
A dipole-quadrupole electron-impact excitation model, consistent with molecular symmetry rules, is presented to fit ro-vibronic spectra of the hydrogen Fulcher-α Q-branch line emissions for passively measuring the rotational temperature of hydrogen neutral molecules in kinetic plasmas with the coronal equilibrium approximation. A quasi-rotational temperature and quadrupole contribution factor are adjustable parameters in the model. Quadrupole excitation is possible due to a violation of the 1st Born approximation for low to medium energy electrons (up to several hundred eV). The Born-Oppenheimer and Franck-Condon approximations are implicitly shown to hold. A quadrupole contribution of 10% is shown to fit experimental data at several temperatures from different experiments with electron energies from several to 100 eV. A convenient chart is produced to graphically determine the vibrational temperature of the hydrogen molecules from diagonal band intensities, if the ground state distribution is Boltzmann. Hydrogen vibrational modes are long-lived, surviving up to thousands of wall collisions, consistent with multiple other molecular dynamics computational results. The importance of inter-molecular collisions during a plasma pulse are also discussed.
Lowest excitation energy of 9Be.
Stanke, Monika; Kedziera, Dariusz; Bubin, Sergiy; Adamowicz, Ludwik
2007-07-27
Variational calculations employing explicitly correlated Gaussian functions and explicitly including the nuclear motion [i.e., without assuming the Born-Oppenheimer (BO) approximation] have been performed to determine the lowest singlet transition energy in the 9Be atom. The non-BO wave functions were used to calculate the alpha2 relativistic corrections (alpha=1/137.035,999,679). With those corrections and with the alpha3 and alpha4 QED corrections determined previously by others, we obtained 54,677.35 cm(-1) for the 3(1)S-->2(1)S transition energy. This result falls within the error bracket for the experimental transition of 54,677.26(10) cm(-1). This is the first time an electronic transition of Be has been calculated from first principles with the experimental accuracy. PMID:17678358
Collisional state-changing of OH- rotations by interaction with Rb atoms in cold traps
NASA Astrophysics Data System (ADS)
González-Sánchez, L.; Carelli, F.; Gianturco, F. A.; Wester, R.
2015-11-01
We employ an accurate, ab initio potential energy surface (PES) which describes the electronic interaction energy between the molecular anion OH- (1Σ+) and the neutral rubidium atom Rb (2 S), to evaluate the elastic and inelastic cross sections over a range of energies representative of the conditions of low-T experiments in MOT traps, when combined with laser-cooled rubidium gas. The system is considered to be in its vibrational ground state, while the first four rotational levels are taken to be involved in the cooling and heating collisional processes that are computed here. The corresponding cooling and heating rates up to about 35 K are obtained from the calculations and compared with the recent results in a similar experiments, where He was the partner atom of the current anion.
Nonequilibrium inhomogeneous steady state distribution in disordered, mean-field rotator systems
NASA Astrophysics Data System (ADS)
Campa, Alessandro; Gupta, Shamik; Ruffo, Stefano
2015-05-01
We present a novel method to compute the phase space distribution in the nonequilibrium stationary state of a wide class of mean-field systems involving rotators subject to quenched disordered external drive and dissipation. The method involves a series expansion of the stationary distribution in inverse of the damping coefficient; the expansion coefficients satisfy recursion relations whose solution requires computing a matrix where about three quarters of the elements vanish, making numerical evaluation simple and efficient. We illustrate our method for the paradigmatic Kuramoto model of spontaneous collective synchronization and for its two mode generalization, in the presence of noise and inertia, and demonstrate an excellent agreement between simulations and theory for the phase space distribution.
Quantum fluctuations of the vortex-lattice state in an ultrafast rotating Bose gas
Li Qiong; Feng Bo; Li Dingping
2011-04-15
Quantum fluctuations in an ultrafast rotating Bose gas at zero temperature are investigated. We calculate the condensate density perturbatively to show that no condensate is present in the thermodynamic limit. The excitation from Gaussian fluctuations around the mean-field solution causes infrared divergences in loop diagrams, nevertheless, in calculating the atom number density, the correlation functions and the free energy, we find that the sum of the divergences in the same loop order vanishes and we obtain finite physical quantities. The long-range correlation is explored and the algebraic decay exponent for the single-particle correlation function is obtained. The atom number density distribution is obtained at the one-loop level, which illustrates the quantum fluctuation effects to melt the mean-field vortex lattice. By the nonperturbative Gaussian variational method, we locate the spinodal point of the vortex-lattice state.
Quantum fluctuations of the vortex-lattice state in an ultrafast rotating Bose gas
NASA Astrophysics Data System (ADS)
Li, Qiong; Feng, Bo; Li, Dingping
2011-04-01
Quantum fluctuations in an ultrafast rotating Bose gas at zero temperature are investigated. We calculate the condensate density perturbatively to show that no condensate is present in the thermodynamic limit. The excitation from Gaussian fluctuations around the mean-field solution causes infrared divergences in loop diagrams, nevertheless, in calculating the atom number density, the correlation functions and the free energy, we find that the sum of the divergences in the same loop order vanishes and we obtain finite physical quantities. The long-range correlation is explored and the algebraic decay exponent for the single-particle correlation function is obtained. The atom number density distribution is obtained at the one-loop level, which illustrates the quantum fluctuation effects to melt the mean-field vortex lattice. By the nonperturbative Gaussian variational method, we locate the spinodal point of the vortex-lattice state.
Glab, W.L.; Glynn, P.T.; Dehmer, P.M.; Dehmer, J.L.
1996-05-01
The authors have used a magnetic bottle photoelectron spectrometer to study the distribution of ion rotational states following photoionization of selected rotational states of the {tilde C}(0,0,0) state of water by 355 nm light. The spectrometer`s kinetic energy resolution of about 4 meV was sufficient to yield rotationally resolved time-of-flight photoelectron spectra. Comparison of the measured and calculated photoelectron spectra is encouraging and reveals unusual photoionization dynamics due to very nonatomic-like behavior in the photoionization continuum and to the presence of Cooper minima. This is the first time that such a test of photoionization theory for a polyatomic molecule at finite kinetic energy has been possible.
Rotation states of the nucleus of Comet Halley compatible with spacecraft images
NASA Astrophysics Data System (ADS)
Abergel, A.; Bertaux, J. L.
1990-07-01
The positions of the nucleus of Comet Halley have been interpreted, for the observations conducted by the flybys of Vegas 1 and 2 and Giotto, with a pure rotation motion and a period of about 54 hours. Comparisons with ground-based estimates of either the angular momentum or the instantaneous rotation axis of the nucleus indicate that the observed rotation axis during the three spacecraft encounters was moving; on this basis it is suggested that the rotation rate of the nucleus cannot be simple, for all that it may not be far from a pure rotation.
Lowest instrumented vertebra selection in AIS.
Erickson, Mark A; Baulesh, David M
2011-01-01
Appropriate selection of the lowest instrumented vertebra (LIV) is crucial to ensure positive outcomes after surgical management of patients with adolescent idiopathic scoliosis. Failure to do so can lead to curve decompensation and "adding on" of additional vertebrae to the deformity. Correct identification of the stable, end, and neutral vertebra, whether the curve(s) is structural or nonstructural, and classifying the type of curve are essential aspects of preoperative planning. Evaluating curve flexibility using fulcrum, side bending, push-prone, and traction can be used to predict the amount of observed postoperative correction for both fused and unfused curves. In addition, these measures can be used to foresee potential residual LIV-tilt and disc wedging postoperatively. Intraoperative techniques such as fine tuning, derotation, wide release, and in situ contouring and instrumentation type used all influence the LIV selection and therefore, must be taken into account preoperatively. Surgical goals when treating adolescent idiopathic scoliosis include achieving a well-balanced spine in all planes while working to preserve segments and therefore, maintain mobility. PMID:21173622
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
Accurate Determination of Rotational Energy Levels in the Ground State of ^{12}CH_4
NASA Astrophysics Data System (ADS)
Abe, M.; Iwakuni, K.; Okubo, S.; Sasada, H.
2013-06-01
We have measured absolute frequencies of saturated absorption of 183 allowed and 21 forbidden transitions in the νb{3} band of ^{12}CH_4 using an optical comb-referenced difference-frequency-generation spectrometer from 86.8 to 93.1 THz (from 2890 to 3100 wn). The pump and signal sources are a 1.06-μ m Nd:YAG laser and a 1.5-μ m extended-cavity laser diode. An enhanced-cavity absorption cell increases the optical electric field and enhances the sensitivity. The typical uncertainty is 3 kHz for the allowed transitions and 12 kHz for the forbidden transitions. Twenty combination differences are precisely determined, and the scalar rotational and centrifugal distortion constants of the ground state are thereby yielded as r@ = l@ r@ = l B_{{s}} (157 122 614.2 ± 1.5) kHz, D_{{s}} (3 328.545 ± 0.031) kHz, H_{{s}} (190.90 ± 0.26) Hz, and L_{{s}} (-13.16 ± 0.76) mHz. Here, B_{{s}} is the rotational constant and D_{{s}}, H_{{s}} and L_{{s}} are the scalar quartic, sextic, octic distortion constants. The relative uncertainties are considerably smaller than those obtained from global analysis of Fourier-transform infrared spectroscopy. S. Okubo, H. Nakayama, K. Iwakuni, H. Inaba and H. Sasada, Opt. Express 19, 23878 (2011). M. Abe, K. Iwakuni, S. Okubo, and H. Sasada, J. Opt. Soc. Am. B (to be published). S. Albert, S. Bauerecker, V. Boudon, L. R. Brown, J. -P. Champion, M. Loëte, A. Nikitin, and M. Quack, Chem. Phys. 356, 131 (2009).
Fast rotating neutron stars with realistic nuclear matter equation of state
NASA Astrophysics Data System (ADS)
Cipolletta, F.; Cherubini, C.; Filippi, S.; Rueda, J. A.; Ruffini, R.
2015-07-01
We construct equilibrium configurations of uniformly rotating neutron stars for selected relativistic mean-field nuclear matter equations of state (EOS). We compute, in particular, the gravitational mass (M ), equatorial (Req) and polar (Rpol) radii, eccentricity, angular momentum (J ), moment of inertia (I ) and quadrupole moment (M2) of neutron stars stable against mass shedding and secular axisymmetric instability. By constructing the constant frequency sequence f =716 Hz of the fastest observed pulsar, PSR J1748-2446ad, and constraining it to be within the stability region, we obtain a lower mass bound for the pulsar, Mmin=[1.2 - 1.4 ]M⊙ , for the EOS employed. Moreover, we give a fitting formula relating the baryonic mass (Mb) and gravitational mass of nonrotating neutron stars, Mb/M⊙=M /M⊙+(13 /200 )(M /M⊙)2 [or M /M⊙=Mb/M⊙-(1 /20 )(Mb/M⊙)2], which is independent of the EOS. We also obtain a fitting formula, although not EOS independent, relating the gravitational mass and the angular momentum of neutron stars along the secular axisymmetric instability line for each EOS. We compute the maximum value of the dimensionless angular momentum, a /M ≡c J /(G M2) (or "Kerr parameter"), (a /M )max≈0.7 , found to be also independent of the EOS. We then compare and contrast the quadrupole moment of rotating neutron stars with the one predicted by the Kerr exterior solution for the same values of mass and angular momentum. Finally, we show that, although the mass quadrupole moment of realistic neutron stars never reaches the Kerr value, the latter is closely approached from above at the maximum mass value, as physically expected from the no-hair theorem. In particular, the stiffer the EOS, the closer the mass quadrupole moment approaches the value of the Kerr solution.
Gao, Fei; Weiland, L.M.; Kitchin, J.R.
2008-05-01
While the acidic polymer electrolyte membrane (PEM) Nafion® has garnered considerable attention, the active response of basic PEMs offers another realm of potential applications. For instance, the basic PEM Selemion® is currently being considered in the development of a CO2 separation prototype device to be employed in coal power plant flue gas. The mechanical integrity of this material and subsequent effects in active response in this harsh environment will become important in prototype development. A multiscale modeling approach based on rotational isomeric state theory in combination with a Monte Carlo methodology may be employed to study mechanical integrity. The approach has the potential to be adapted to address property change of any PEM in the presence of foreign species (reinforcing or poisoning), as well as temperature and hydration variations. The conformational characteristics of the Selemion® polymer chain and the cluster morphology in the polymer matrix are considered in the prediction of the stiffness of Selemion® in specific states.
Rotation-vibrational states of H3+ and the adiabatic approximation.
Alijah, Alexander; Hinze, Juergen
2006-11-15
We discuss recent progress in the calculation and identification of rotation-vibrational states of H3+ at intermediate energies up to 13,000 cm(-1). Our calculations are based on the potential energy surface of Cencek et al. which is of sub-microhartree accuracy. As this surface includes diagonal adiabatic and relativistic corrections to the fixed nuclei electronic energies, the remaining discrepancies between our calculated and experimental data should be due to the neglect of non-adiabatic coupling to excited electronic states in the calculations. To account for this, our calculated energy values were adjusted empirically by a simple correction formula. Based on our understanding of the adiabatic approximation, we suggest two new approaches to account for the off-diagonal adiabatic correction, which should work; however, they have not been tested yet for H3+. Theoretical predictions made for the above-barrier energy region of recent experimental interest are accurate to 0.35 cm(-1) or better. PMID:17015396
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.
A prediction of the rotational states for partially deuterated ammonium ions in NH4 - xDxClO4
NASA Astrophysics Data System (ADS)
Maki, Kazuo
1983-01-01
Splittings of the librational ground state of partially deuterated ammonium ions in the ammonium perchlorate crystal are calculated. Heat capacity anomalies are predicted to be observed at around 1-3 K, a careful measurement of which will be very useful for characterizing the anisotropy of the rotational potential.
Niane, Aliou; Dath, Cheikh Amadou Bamba; Faye, Ndèye Arame Boye; Hammami, Kamel; Jaidane, Nejm-Eddine
2014-01-01
A theoretical study of rotational collision of LiH(X(1)Σ(+),v = 0, J) with Ar has been carried out. The ab initio potential energy surface (PES) describing the interaction between the Ar atom and the rotating LiH molecule has been calculated very accurately and already discussed in our previous work [Computational and Theoretical Chemistry 993 (2012) 20-25]. This PES is employed to evaluate the de-excitation cross sections. The ab initio PES for the LiH(X(1)Σ(+))-Ar((1)S) Van der waals system is calculated at the coupled-cluster [CCSD(T)] approximation for a LiH length fixed to an experimental value of 3.0139 bohrs. The basis set superposition error (BSSE) is corrected and the bond functions are placed at mid-distance between the center of mass of LiH and the Ar atom. The cross sections are then derived in the close coupling (CC) approach and rate coefficients are inferred by averaging these cross sections over a Maxwell-Boltzmann distribution of kinetic energies. The 11 first rotational levels of rate coefficients are evaluated for temperatures ranging from 10 to 300 K. We notice that the de-excitation rate coefficients appear large in the order 10(-10) cm(-3) s(-1) and show very low temperature dependence. The rate coefficients magnify significantly the propensity toward ∆ J = -1 transitions. These results confirm the same propensity already noted for the cross sections. PMID:24808997
The lowest frequency vibrational fundamental of disilane: A three-band analysis
NASA Astrophysics Data System (ADS)
Borvayeh, L.; Moazzen-Ahmadi, N.; Horneman, V.-M.
2007-04-01
The lowest frequency perpendicular fundamental band ν9 of disilane has been analyzed to investigate torsion mediated vibrational interactions. We report here a three-band analysis involving torsional levels built on the ground state, the ν9 vibrational fundamental, and ν3 fundamental. This analysis includes transitions from the far-infrared torsional bands, ν4, 2 ν4 - ν4, 3 ν4 - 2 ν4, two perturbation-allowed rotational series from the overtone band 3 ν4 and transitions restricted to -21 ⩽ kΔ k ⩽ 21 in the ν9 fundamental band. An excellent fit to the included data was obtained. Two interactions are identified in this fit, a resonant Coriolis interaction between the ν9 torsional stack and that of the ground vibrational state and a Fermi interaction between the ν3 fundamental and the gs. The introduction of the Fermi interaction causes a large change in the barrier height for the ground vibrational state and makes the barrier shape parameter redundant, indicating that the vibrational contributions to the experimental barrier shape are dominant. Such effects have also been observed for ethane and other similar molecules.
Lifetimes of Vibro-Rotational Levels in Excited Electronic States of Diatomic Hydrogen Isotopologues
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.
Shape model and rotational state of dwarf planet Ceres from Dawn FC stereo images
NASA Astrophysics Data System (ADS)
Preusker, F.; Scholten, F.; Matz, K.-D.; Roatsch, T.; Elgner, S.; Jaumann, R.; Joy, S. P.; Polanskey, C. A.; Raymond, C. A.; Russell, C. T.
2015-10-01
In 2012, the Dawn mission completed its 14-month observation campaign at asteroid (4) Vesta and entered in March 2015 successfully into the orbit around its final target - the dwarf planet Ceres. Similar to the mapping strategy at Vesta, Ceres will be imaged in three different altitude orbits [1] Survey, High Altitude Mapping Orbit (HAMO), and Low Altitude Mapping Orbit (LAMO) using the onboard camera Dawn FC [2]. In June 2015 Dawn is going to start its Survey orbit and will acquire about 920 clear filter images with a resolution of about 400 m/pixel in eight different cycles. In each cycle Ceres will be mapped completely under similar illumination conditions (Sun elevation and azimuth), but different viewing conditions (by slewing the spacecraft offnadir). This will allow us to analyze the images stereoscopically and to construct stereo topographic maps. The topography is particularly important because it is essential for derivation of physical properties of Ceres, precise ortho-image registration, mosaicking, and map generation of monochrome/color FC images and VIR images [3]. Furthermore we will determine a precise description of the rotational state of Ceres.
Ott, C D; Dimmelmeier, H; Marek, A; Janka, H-T; Hawke, I; Zink, B; Schnetter, E
2007-06-29
We present 2D and 3D simulations of the collapse of rotating stellar iron cores in general relativity employing a nuclear equation of state and an approximate treatment of deleptonization. We compare fully general relativistic and conformally flat evolutions and find that the latter treatment is sufficiently accurate for the core-collapse supernova problem. We focus on gravitational wave (GW) emission from rotating collapse, bounce, and early postbounce phases. Our results indicate that the GW signature of these phases is much more generic than previously estimated. We also track the growth of a nonaxisymmetric instability in one model, leading to strong narrow-band GW emission. PMID:17678077
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.
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.
NASA Astrophysics Data System (ADS)
Chen, Li-Bing; Jin, Rui-Bo; Lu, Hong
Teleportation of quantum gates using partially entangled states is considered. Different from the known probability schemes, we propose and study a method for teleporting a prototypical single-qubit rotation on a remote receiver with unit fidelity and unit probability by using two partially entangled pairs. The method is applicable to any two partially entangled pairs satisfying the condition that their smaller Schmidt coefficients γ and η are (2γ+2η-2γη-1)≥0. In our scheme, the sender's local generalized measurement described by a positive operator-valued measurement (POVM) lies at the heart. We construct the required POVM. The fact that the controlled teleportation of single-qubit rotation could be realized exactly using two partially entangled pairs is also notable. A sender could teleport a rotation on a remote receiver, an arbitrary one of the two receivers, via the control of the other in a network.
NASA Astrophysics Data System (ADS)
Kunishige, Sachi; Katori, Toshiharu; Baba, Masaaki; Hayashi, Masato; Hasegawa, Hirokazu; Ohshima, Yasuhiro
2015-12-01
High-resolution spectra of the S1←S0 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 S1 state. The degenerate 61 levels of C6H6 or C6D6 are split into 6a1 and 6b1 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.
Kunishige, Sachi; Katori, Toshiharu; Baba, Masaaki; Hayashi, Masato; Hasegawa, Hirokazu; Ohshima, Yasuhiro
2015-12-28
High-resolution spectra of the S1←S0 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 S1 state. The degenerate 6(1) levels of C6H6 or C6D6 are split into 6a(1) and 6b(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. PMID:26723667
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].
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.
Weber, F. |; Glendenning, N.K.
1993-10-25
In this paper the following items will be treated: The present status of dense nuclear matter calculations and constraints on the behavior of the associated equation of state at high densities from data on rapidly rotating pulsars. Recent finding of the likely existence of a mixed phase of baryons and quarks forming a coulomb lattice in the dense cores of neutron stars. Review of important findings of recently performed calculations of rapidly rotating compact stars. These are constructed in the framework of general relativity theory for a representative collection of realistic nuclear equations of state. Establish the minimum-possible rotational periods of gravitationally bound neutron stars and self-bound strange stars. Its knowledge is of fundamental importance for the decision between pulsars that can be understood as rotating neutron stars and those that cannot (signature of hypothetical self-bound matter of which strange stars are the likely stellar candidates. Investigate the properties of sequences of strange stars. Specifically, we answer the question whether such objects can give rise to the observed phenomena of pulsar glitches, which is at the present time the only astrophysical test of the strange-quark-matter hypothesis.
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.
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
NASA Astrophysics Data System (ADS)
Chandra, N.; Chakraborty, M.
1991-11-01
In this paper we report theoretical studies of angle-resolved photoelectron spectroscopy (ARPES) and of circular dichroism in photoelectron angular distribution (CDAD) for ionization in molecules oriented in a single ‖JKJMJ> rotational eigenstate. These processes have been investigated also as two of the possible alternatives to photodissociation to determine orientational distribution function of rotationally state selected, oriented molecules. Expressions are derived which can be used to calculate ARPES and CDAD for such molecular species from ab initio methods or to analyze these experimentally observed spectra for extracting information about the degree of orientation of the molecular framework. These formulas are put in their simplest possible forms using the transformation properties of the molecular point group to their full advantage. The ionization amplitude is thus shown to decompose into a sum of transitions each involving the final state wave function belonging to an irreducible representation of the point group of the target molecule. It is found that, similar to the case of photodissociation, one can determine the rotational quantum number J purely from experimental photoionization data. Expressions developed herein are used to study ARPES and CDAD for ionization in a1 orbital of those rotationally state selected and oriented spherical top molecules which transform according to the Td point symmetry group. In this case, the detection-integrated cross section, singly differential in molecular orientation, is found to be independent of the photoionization dynamics and directly gives the molecular orientational function. The other ARPES and CDAD formulas are shown to depend upon the dynamics through the integrated partial cross section σ¯, the angularly asymmetry parameter β¯, the phase shift of the continuum waves representing the photoelectron, and the phase of the dipole transition amplitudes. The formulation presented in this paper sets a
NASA Astrophysics Data System (ADS)
Koroleva, L. A.; Krasnoshchekov, S. V.; Matveev, V. K.; Pentin, Yu. A.
2016-08-01
The structural parameters of s- trans- and s- cis-isomers of a methacrolein molecule in the ground ( S 0) electronic state are determined by means of MP2 method with the cc-pVTZ basis set. Kinematic factor F(φ) is expanded in a Fourier series. The potential function of internal rotation (PFIR) of methacrolein in this state is built using experimental frequencies of transitions of the torsional vibration of both isomers, obtained from an analysis of the vibrational structure of the high-resolution UV spectrum with allowance for the geometry and difference between the energy (Δ H) of the isomers. It is shown that the V n parameters of the potential function of internal rotation of the molecule, built using the frequencies of the transition of the torsional vibrations of s- trans- and s- cis-isomers of the methacrolein molecule, determined from vibrational structure of the high-resolution UV spectrum and the FTIR spectrum, are close.
Selective control of the states of multilevel quantum systems using nonselective rotation operators
Zobov, V. E. Shauro, V. P.
2009-01-15
We have calculated the sequences of nonselective rotation operators separated by intervals of free evolution that perform selective rotations between adjacent levels in systems with three, four, five, and six nonequidistant levels. We have numerically simulated the realization of the calculated sequences for quadrupole nuclei with corresponding spins controlled by intense nonselective radio-frequency (RF) pulses and investigated the dependences of the realization error on the parameters of external and internal interactions. To reduce the error when the RF field is not strong enough, we have found composite nonselective RF pulses consisting of five simple ones. We show that the error of the composite selective rotation operator can be reduced signifi- cantly in comparison to the error of a simple single selective pulse.
Quantum state-resolved study of pure rotational excitation of CO sub 2 by hot atoms
Hershberger, J.F.; Hewitt, S.A.; Sarkar, S.K.; Flynn, G.W. ); Weston, R.E. Jr.
1989-10-15
Rotationally inelastic scattering of carbon dioxide by translationally hot H, D, and Cl atoms was studied by time-resolved diode laser absorption. The high {ital J} rotational distribution falls off quite rapidly between {ital J}=60 and {ital J}=80. D atom collisions have roughly twice the excitation cross section versus H atom collisions, with the H*/D* ratio decreasing with increasing {ital J}. These results are consistent with a constraint on the total reagent orbital angular momentum available for rotational excitation. Transient Doppler profiles measured immediately after hot atom/CO{sub 2} collisions indicate that CO{sub 2} molecules excited to high {ital J} levels have a larger recoil velocity than molecules excited to lower {ital J} levels. This result is consistent with predictions based on a simple model which treats the CO{sub 2} potential as a hard shell ellipsoid.
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
NASA Astrophysics Data System (ADS)
Bizzocchi, L.; Esposti, C. Degli
2001-10-01
The unstable FBS molecule has been produced in the gas phase by a high-temperature reaction between crystalline boron and sulfur tetrafluoride. Its rotational spectrum has been observed in the millimeter-wave region, from 75 to 460 GHz, for different isotopic species and vibrational states. All the excited states which approximately lie below 1700 cm-1, that are 1000 (F-B stretch), 0110 (FBS bend), 0001 (B=S stretch), 2000, 0200, 0220, 0310, 0330, 0400, 0420, 0440, 1110, 1200, and 1220, have been investigated for the most abundant isotopomer F11B32S. The analysis of the spectra has been performed taking simultaneously into account the Fermi interaction which couples the states ν1,ν2,ν3 with ν1-1, ν2+2,ν3, and l-type resonances between different sublevels of a given vibrational bending state. This procedure allowed us to calculate directly deperturbed parameters and, in addition, yielded reliable estimates of the vibrational energy difference between the interacting levels and of the normal coordinate cubic force constant k122. Rotational spectra in the ground and various excited states have been also recorded and analyzed for the less abundant isotopic species F10B32S, F11B34S, F10B34S, F11B33S, and F10B33S. The very weak spectrum in the 0001 state was successfully observed for the pair of isotopomers F11B32S and F10B32S, whose equilibrium rotational constants could be accurately calculated yielding the first evaluation of the equilibrium structure of fluorothioborine: re(F-B)=1.2762±0.0002 Å and re(B=S)=1.6091±0.0002 Å.
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
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
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 rapid 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, Χ_{b}, 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 Χ_{m}, which estimates the time it takes for surface fluxes to moisten the midtroposphere. A smaller Χ_{m} 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.
NASA Astrophysics Data System (ADS)
Zhou, Wenyu
2015-12-01
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 rapid 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.
Deep, Low Mass Ratio Overcontact Binary Systems. V. The Lowest Mass Ratio Binary V857 Herculis
NASA Astrophysics Data System (ADS)
Qian, S.-B.; Zhu, L.-Y.; Soonthornthum, B.; Yuan, J.-Z.; Yang, Y.-G.; He, J.-J.
2005-09-01
Charge-coupled device (CCD) photometric light curves in the B, V, and R bands of the complete eclipsing binary star V857 Her are presented. It is shown that the light curves of the W UMa-type binary are symmetric and of A type according to Binnendijk's classification. Our four epochs of light minimum along with others compiled from the literature were used to revise the period and study the period change. Weak evidence indicates that the orbital period of V857 Her may show a continuous increase at a rate of dP/dt=+2.90×10-7 days yr-1. The photometric parameters of the system were determined with the 2003 version of the Wilson-Devinney code. It is shown that V857 Her is a deep overcontact binary system with f=83.8%+/-5.1%. The derived mass ratio of q=0.06532+/-0.0002 suggests that it has the lowest mass ratio among overcontact binary systems. As the orbital period increases, the decrease of the mass ratio will cause it to evolve into a single rapidly rotating star when it meets the more familiar criterion that the orbital angular momentum be less than 3 times the total spin angular momentum. To understand the evolutionary state of the system, long-term photometric monitoring and spectroscopic observations will be required.
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).
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.
Bartley, J.M. ); Glazner, A.F. )
1991-12-01
Two areas of intense early Miocene crustal extension in the southwestern United States, the Colorado River trough and the central Mojave Desert, are separated by a weakly deformed area in the eastern Mojave Desert. The authors propose that these areas form a left-stepping en echelon rift system linked by a ductile detachment at depth. The en echelon geometry explains the southward loss of displacement in the central Mojave Desert and northward loss of coeval displacement in the Colorado River trough, and it incorporates seismic reflection evidence that mid-crustal Tertiary extensional mylonites continue beneath the weakly deformed area. This geometry also explains clockwise paleomagnetic declination anomalies from lower Miocene rocks as recording thin-skinned, detached rotations; large-scale block rotations are not required. Obliquity of the northeast-trending crustal-extension vector to the east-west-trending early Miocene synextensional volcanic belt may have caused the en echelon pattern to develop.
High-pressure magnetic state of MnP probed by means of muon-spin rotation
NASA Astrophysics Data System (ADS)
Khasanov, R.; Amato, A.; Bonfà, P.; Guguchia, Z.; Luetkens, H.; Morenzoni, E.; De Renzi, R.; Zhigadlo, N. D.
2016-05-01
We report a detailed muon-spin rotation study of the pressure evolution of the magnetic order in the manganese-based pnictide MnP, which has been recently found to undergo a superconducting transition under pressure once the magnetic ground state is suppressed. Using the muon as a volume sensitive local magnetic probe, we identify a ferromagnetic state as well as two incommensurate helical states (with propagation vectors Q aligned along the crystallographic c and b directions, respectively) which transform into each other through first-order phase transitions as a function of pressure and temperature. Our data suggest that the magnetic state from which superconductivity develops at higher pressures is an incommensurate helical phase.
González, José; Molina, Rafael A
2016-04-15
We investigate the development of novel surface states when 3D Dirac or Weyl semimetals are placed under circularly polarized electromagnetic radiation. We find that the hybridization between inverted Floquet bands opens, in general, a gap, which closes at so-called exceptional points found for complex values of the momentum. This corresponds to the appearance of midgap surface states in the form of evanescent waves decaying from the surface exposed to the radiation. We observe a phenomenon reminiscent of Landau quantization by which the midgap surface states get a large degeneracy proportional to the radiation flux traversing the surface of the semimetal. We show that all of these surface states carry angular current, leading to an angular modulation of their charge that rotates with the same frequency of the radiation, which should manifest in the observation of a macroscopic chiral current in the irradiated surface. PMID:27127980
NASA Astrophysics Data System (ADS)
González, José; Molina, Rafael A.
2016-04-01
We investigate the development of novel surface states when 3D Dirac or Weyl semimetals are placed under circularly polarized electromagnetic radiation. We find that the hybridization between inverted Floquet bands opens, in general, a gap, which closes at so-called exceptional points found for complex values of the momentum. This corresponds to the appearance of midgap surface states in the form of evanescent waves decaying from the surface exposed to the radiation. We observe a phenomenon reminiscent of Landau quantization by which the midgap surface states get a large degeneracy proportional to the radiation flux traversing the surface of the semimetal. We show that all of these surface states carry angular current, leading to an angular modulation of their charge that rotates with the same frequency of the radiation, which should manifest in the observation of a macroscopic chiral current in the irradiated surface.
NASA Astrophysics Data System (ADS)
Brouard, M.; Mabbs, R.
1993-03-01
A reinvestigation of the vibrationally mediated photodissociation spectrum of the 3rd OH stretching overtone (4 vOH) of jetcooled H 2O 2, first observed by Crim and co-workers, reveals anomalous double resonance spectral intensities compared with those observed via high-resolution absorption spectroscopy. The origin of these intensity perturbations is traced to J' KaKc level dependent variations in the photodissociation cross section, δ 00, out of the intermediate overtone state. The photofragment OH(X, v=0) rotational state distribution generated by photodissociation of H 2O 2 (4 vOH, J' KaKc=2 02) has been determined. Combined with the relative cross-section data, these results imply that delocalization of the overtone state wavefunction into wideamplitude OO stretching regions of the ground state is profoundly influenced by parent molecular rotation, primarily about the a and b axes. The intermediate state with J'=0 is shown to be much more highly localized, and hence more likely to display mode selective behaviour, than its J' >0 counterparts.
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.
The rotational spectrum of the NH+ radical in its X 2Pi and a 4Sigma- states.
Hübers, Heinz-Wilhelm; Evenson, Kenneth M; Hill, Christian; Brown, John M
2009-07-21
Transitions between the spin-rotational levels of the (14)NH(+) radical in the v = 0 levels of its X (2)Pi and a (4)Sigma(-) states have been studied by the technique of laser magnetic resonance at far-infrared wavelengths. The data have been combined with a previous zero-field measurement of the J = 1 1/2 - 1/2 transition frequencies at 1.01 THz to determine a much improved set of molecular parameters for NH(+) in the X (2)Pi state; the major parameters for the a (4)Sigma(-) state have also been determined. A full determination of the hyperfine parameters for both (14)N and (1)H nuclei has been achieved for the first time. Accurate predictions of the transition frequencies between the low-lying levels of the radical in the absence of a magnetic field have also been made, including lambda-doubling frequencies for use by radio astronomers. PMID:19624201
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)). PMID:24295035
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
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
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
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.
The rotational spectrum of nitric acid - The first five vibrational states
NASA Technical Reports Server (NTRS)
Crownover, Richard L.; Booker, Randy A.; De Lucia, Frank C.; Helminger, Paul
1988-01-01
The details of work on the nu(8) vibrational state, which arise from the NO2 out-of-plane vibration, are reported. For this state, over 210 transitions have been measured in the millimeter and submillimeter spectral region and analyzed with Watson's A-reduced centrifugal distortion Hamiltonian. Also included in this work is a comparison of all these spectra and an overview of the millimeter and submillimeter spectra associated with these states. Although at the high sensitivity available in laboratory experiments, many additional lines are observable, all arise from vibrational states whose populations are more than 100 times lower than the ground state. The most prominent of these are due to the states which give rise to the perturbed 2 nu(9) and nu(5) bands near 11 microns. These results provide a significant data base for both atmospheric remote sensing experiments and spectral analyses of data in other spectral regions, especially the IR.
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.
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
Excitation of the ground state rotational band in 20Ne by 0.8 GeV protons
NASA Astrophysics Data System (ADS)
Blanpied, G. S.; Balchin, G. A.; Langston, G. E.; Ritchie, B. G.; Barlett, M. L.; Hoffmann, G. W.; McGill, J. A.; Franey, M. A.; Gazzaly, M.; Wildenthal, B. H.
1984-10-01
Angular distributions for the scattering of 0.8 GeV polarized protons from the ground state rotational band in 20Ne are reported. Cross sections and analyzing powers for protons exciting these states were measured with a high resolution spectrometer. Coupled channels and distorted wave Born approximation analyses of scattering data for the 0+, 2+, 4+, and experimentally unresolved 6+ states are presented. The observed cross section data for the 0+, 2+, and 4+ states are reproduced quite well with the coupled channels calculations, and the large hexadecapole deformation reported previously is confirmed. The distorted wave Born approximation results are equally good for the 0+ angular distribution, but are a significantly poorer representation of the cross section data for the 2+ and 4+ states. Both calculations do equally well in explaining the 0+ analyzing power data and both fail to explain the 4+ analyzing power data past the region of the first maximum. The coupled channels results do a better job in explaining the 2+ analyzing power data. The multipole moments of the deformed optical potential used in the coupled channels calculations are related to those of the matter distributions by Satchler's theorem. These are compared to the moments found using other hadronic probes, those of the charge distribution determined by electromagnetic measurements, and to moments from shell model and Hartree-Fock calculations.
Yamaki, Masahiro; Teranishi, Yoshiaki; Nakamura, Hiroki; Lin, Sheng Hsien; Fujimura, Yuichi
2016-01-21
The electron angular momentum is a fundamental quantity of high-symmetry aromatic ring molecules and finds many applications in chemistry such as molecular spectroscopy. The stationary angular momentum or unidirectional rotation of π electrons is generated by the excitation of a degenerated electronic excited state by a circularly-polarized photon. For low-symmetry aromatic ring molecules having non-degenerate states, such as chiral aromatic ring molecules, on the other hand, whether stationary angular momentum can be generated or not is uncertain and has not been clarified so far. We have found by both theoretical treatments and quantum optimal control (QOC) simulations that a stationary angular momentum can be generated even from a low-symmetry aromatic ring molecule. The generation mechanism can be explained in terms of the creation of a dressed-state, and the maximum angular momentum is generated by the dressed state with an equal contribution from the relevant two excited states in a simple three-electronic state model. The dressed state is formed by inducing selective nonresonant transitions between the ground and each excited state by two lasers with the same frequency but having different polarization directions. The selective excitation can be carried out by arranging each photon-polarization vector orthogonal to the electronic transition moment of the other transition. We have successfully analyzed the results of the QOC simulations of (P)-2,2'-biphenol of axial chirality in terms of the analytically determined optimal laser fields. The present findings may open up new types of chemical dynamics and spectroscopy by utilizing strong stationary ring currents and current-induced magnetic fields, which are created at a local site of large compounds such as biomolecules. PMID:26670839
Park, Se-Jin; Kim, Eugene; Jeong, Hwa Jae; Lee, Jinmyung; Park, Shinsuk
2012-01-01
Background: Accurate reduction of rotational displacement for transverse or comminute fracture of humeral shaft fracture is difficult during operation. The purpose of this study was to evaluate the reliability of the bicipital groove as a point of reference for the prediction of the rotational state of the humerus on two dimensional images of C-arm image intensifier during operation for humeral shaft fractures. Materials and Methods: One hundred subjects, 62 male, 38 female, aged 22-53 years were recruited contralateral bicipital groove on the 45 degrees externally rotational standard anterior-posterior view recorded before surgery. Three observers, watched only contour of bicipital groove in monitor of C-arm image intensification with naked eye without looking at the subject and predicted rotational state of the humerus by comparing the contour of the opposite side of bicipital groove. The angle of discrepancy from real rotational position was then assessed. Results: The mean (SD), angular discrepancy between the neutral point and the predicted angle was 3.4°(±2.7°). A value within 5° was present in 72% of cases. All observations were within 15°. There was no interobserver variation (P = 0.47). The intraclass correlation coefficient (ICC) was 0.847. Conclusion: Contour of the bicipital groove on simple radiograph was a useful landmark. Comparing the contour of the bicipital groove in the 45 degrees externally rotational standard view bilaterally, was an effective method for reduction of rotational displacement of the humerus. PMID:23325971
Particle mixing in rotating fluidized beds: Inferences about the fluidized state
Qian, G.H.; Bagyi, I.; Pfeffer, R.; Shaw, H.; Stevens, J.G.
1999-07-01
Particle motion in a rotating fluidized bed was studied by observing the mixing of two layers of particles of different colors. The particles in the two layers were either nearly identical, except for their color, or were of different density and size distribution. All of the particles were in the Geldart-A classification for conventional fluidized beds. After fluidization, but before mixing, the bed exhibited some fluid-like behavior, that is, the inner surface became radially uniform. For particle layers of the same material, mixing occurred after U{sub mfc} was reached, with bubbles observed at the mixing velocity. No experimental difference between U{sub mb} and U{sub mfc} could be discerned; they either coincided or were nearly equal. Bubbles appeared to be responsible for particle motion and mixing. When the denser particles are placed on the distributor, the mixing behavior was similar to that observed for layers of the same material. However, when the less dense particles are placed on the distributor, mixing is dominated by differences in density and occurs before bubbles are visible.
Vaz, W L; Austin, R H; Vogel, H
1979-01-01
A derivative of the integral membranes protein, cytochrome b5, has been prepared in which the native heme group has been replaced by the structurally similar rhodium(III)-protoporphyrin IX. This metalloporphyrin has a finite triplet yield with a single exponential decay time of 22 microsecond in water. After insertion of the metalloporphyrin into the protein, its triplet-state decay becomes strongly nonexponential with at least three equal amplitude components with time constants varying over a range of 100. The derivatized protein has been incorporated into unilamellar liposomes prepared from dimyristoyllecithin, and the rotational diffusion of the protein in the lipid bilayer has been studied at temperatures above and below the lipid phase transition temperature via triplet absorbance anisotropy decay. The anisotropy decay curves are biphasic both above and below the lipid phase transition. The rotational diffusion constant is found to be 2.4 X 10(5) s-1 at 35 degrees C, and 1.1 X 10(4) s-1 at 10 degrees C, both being calculated from the fast decay component. The ratio of the limiting anisotropy to the initial anisotropy is 0.6 at both temperatures. This implies a cone of restricted motion of 34 degrees for the protein in the bilayer. PMID:262426
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.
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
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. PMID:27376104
Schmidt-May, Alice F; Grütter, Monika; Neugebohren, Jannis; Kitsopoulos, T N; Wodtke, Alec M; Harding, Dan J
2016-07-14
We present a 1 + 1' resonance-enhanced multiphoton ionization (REMPI) scheme for acetylene via the linear G̃ 4sσ (1)Πu Rydberg state, offering partial rotational resolution and the possibility to detect excitation in both the cis- and trans-bending modes. The resonant transition to the G̃ state is driven by a vacuum ultraviolet (VUV) photon, generated by resonant four-wave mixing (FWM) in krypton. Ionization from the short-lived G̃ state then occurs quickly, driven by the high intensity of the residual light from the FWM process. We have observed nine bands in the region between 79 200 cm(-1) and 80 500 cm(-1) in C2H2 and C2D2. We compare our results with published spectra in this region and suggest alternative assignments for some of the Renner-Teller split bands. Similar REMPI schemes should be applicable to other small molecules with picosecond lifetime Rydberg states. PMID:27073931
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
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.
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.
Technology Transfer Automated Retrieval System (TEKTRAN)
Fruit rot, caused by Phytophthora capsici is a prevalent disease in most watermelon producing regions of the world. The disease was first reported in 1940 in Florida. It is particularly severe in the southeastern United States, where about 50% of the watermelon fruit are produced (FL, GA, AL, SC, N...
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.
NASA Astrophysics Data System (ADS)
Leary, C. C.; Reeb, D.; Raymer, M. G.
2008-10-01
Solution of the Dirac equation predicts that when an electron with nonzero orbital angular momentum (OAM) propagates in a cylindrically symmetric potential, its spin and orbital degrees of freedom interact, causing the electron's phase velocity to depend on whether its spin angular momentum (SAM) and OAM vectors are oriented parallel or anti-parallel with respect to each other. This spin-orbit splitting of the electronic dispersion curves can result in a rotation of the electron's spatial state in a manner controlled by the electron's own spin z-component value. These effects persist at non-relativistic velocities. To clarify the physical origin of this effect, we compare solutions of the Dirac equation to perturbative predictions of the Schrödinger-Pauli equation with a spin-orbit term, using the standard Foldy-Wouthuysen Hamiltonian. This clearly shows that the origin of the effect is the familiar relativistic spin-orbit interaction.
Kostenko, Arseni; Tumanskii, Boris; Karni, Miriam; Inoue, Shigeyoshi; Ichinohe, Masaaki; Sekiguchi, Akira; Apeloig, Yitzhak
2015-10-01
We report the first direct spectroscopic observation by electron paramagnetic resonance (EPR) spectroscopy of a triplet diradical that is formed in a thermally induced rotation around a main-group π bond, that is, the SiSi double bond of tetrakis(di-tert-butylmethylsilyl)disilene (1). The highly twisted ground-state geometry of singlet 1 allows access to the perpendicular triplet diradical 2 at moderate temperatures of 350-410 K. DFT-calculated zero-field splitting (ZFS) parameters of 2 accurately reproduce the experimentally observed half-field transition. Experiment and theory suggest a thermal equilibrium between 1 and 2 with a very low singlet-triplet energy gap of only 7.3 kcal mol(-1) . PMID:26297814
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.
NASA Astrophysics Data System (ADS)
Jin, Jingjing; Zhang, Suying; Han, Wei; Wei, Zhifeng
2013-04-01
We investigate the ground states and spin textures of rotating two-component Bose-Einstein condensates (BECs) confined in an annular potential. For the two-component miscible BECs, we analytically give the critical angular velocity of each component with the Thomas-Fermi approximation (TFA), at which the density profile changes from a disc shape into an annulus shape, forming a giant vortex. We present a phase diagram showing three kinds of density profiles of the ground states that are two disc shaped, one disc and another annulus shaped, and two annulus shaped. For the two-component immiscible BECs with particle number grave imbalance, we also discuss their ground states using the TFA, and three kinds of symmetrical structures of the density profiles are classified analytically. The spin textures of the two-component immiscible BECs have been studied and we find three kinds of symmetrical structures of the spin textures in the annular trap. One of these textures is an annular skyrmion which has been observed in harmonic potentials. Both of the other spin textures contain a new structure composed of concentric double-annulus skyrmion whose topological charge is the sum of the ones of two annular skyrmions, and the topological charge of each annular skyrmion is equal to the absolute value of the difference between the quantum numbers of circulation of two components inside this annular skyrmion. We also prove that these new textures are robust by investigating the dynamical behaviours of the system under external disturbances.
Towards rotationally state-resolved differential cross sections for the hydrogen exchange reaction
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.
Towards rotationally state-resolved differential cross sections for the hydrogen exchange reaction
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.
Translation-rotation states of H2 in C60: New insights from a perturbation-theory treatment.
Felker, Peter M; Bačić, Zlatko
2016-08-28
We report an investigation of the translation-rotation (TR) level structure of H2 entrapped in C60, in the rigid-monomer approximation, by means of a low-order perturbation theory (PT). We focus in particular on the degree to which PT can accurately account for that level structure, by comparison with the variational quantum five-dimensional calculations. To apply PT to the system, the interaction potential of H2@C60 is decomposed into a sum over bipolar spherical tensors. A zeroth-order Hamiltonian, Hˆ0, is then constructed as the sum of the TR kinetic-energy operator and the one term in the tensor decomposition of the potential that depends solely on the radial displacement of the H2 center of mass (c.m.) from the cage center. The remaining terms in the potential are treated as perturbations. The eigenstates of Hˆ0, constructed to also account for the coupling of the angular momentum of the H2 c.m. about the cage center with the rotational angular momentum of the H2 about the c.m., are taken as the PT zeroth-order states. This zeroth-order level structure is shown to be an excellent approximation to the true one except for two types of TR-level splittings present in the latter. We then show that first-order PT accounts very well for these splittings, with respect to both their patterns and magnitudes. This allows one to connect specific features of the level structure with specific features of the potential-energy surface, and provides important new physical insight into the characteristics of the TR level structure. PMID:27586925
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...
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...
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...
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...
48 CFR 47.306-2 - Lowest overall transportation costs.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 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...
Emani, Prashant S; Olsen, Gregory L; Echodu, Dorothy C; Varani, Gabriele; Drobny, Gary P
2010-12-01
Functional RNA molecules are conformationally dynamic and sample a multitude of dynamic modes over a wide range of frequencies. Thus, a comprehensive description of RNA dynamics requires the inclusion of a broad range of motions across multiple dynamic rates which must be derived from multiple spectroscopies. Here we describe a slow conformational exchange theoretical approach to combining the description of local motions in RNA that occur in the nanosecond to microsecond window and are detected by solid-state NMR with nonrigid rotational motion of the HIV-1 transactivation response element (TAR) RNA in solution as observed by solution NMR. This theoretical model unifies the experimental results generated by solution and solid-state NMR and provides a comprehensive view of the dynamics of HIV-1 TAR RNA, a well-known paradigm of an RNA where function requires extensive conformational rearrangements. This methodology provides a quantitative atomic level view of the amplitudes and rates of the local and collective displacements of the TAR RNA molecule and provides directly motional parameters for the conformational capture hypothesis of this classical RNA-ligand interaction. PMID:21067190
NASA Astrophysics Data System (ADS)
Delahaye, Thibault; Nikitin, Andrei; Rey, Michaël; Szalay, Péter G.; Tyuterev, Vladimir G.
2014-09-01
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 12C2H4, 13C2H4, and 12C2D4 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 13C2H4 and 12C2D4 and rovibrational levels of 12C2H4.
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
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
Rotating trapped Bose-Einstein condensates
NASA Astrophysics Data System (ADS)
Fetter, A. L.
2008-01-01
Trapped Bose-Einstein condensates (BECs) differ considerably from the standard textbook example of a uniform Bose gas. In an isotropic harmonic potential V( r) = ½ Mω2 r 2, the single-particle ground state introduces a new intrinsic scale of length [the ground-state size d = √ ℏ/( Mω)] and energy [the ground-state energy E 0 = frac{3} {2} ℏω]. When the trap rotates at a low angular velocity, the behavior of a single vortex illustrates the crucial role of discrete quantized vorticity. For more rapid rotation, the condensate contains a vortex array. The resulting centrifugal forces expand the condensate radially and shrink it axially; thus, the condensate becomes effectively two dimensional. If the external rotation speed approaches the frequency of the radial harmonic confining potential, the condensate enters the "lowest-Landau-level" regime, and a simple description again becomes possible. Eventually, the system is predicted to make a quantum phase transition to a highly correlated state analogous to the fractional quantum Hall states of electrons in a strong magnetic field.
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
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
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
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.
NASA Astrophysics Data System (ADS)
Endres, C. P.; Drouin, B. J.; Pearson, J. C.; Müller, H. S. P.; Lewen, F.; Schlemmer, S.; Giesen, T. F.
2009-09-01
Dimethyl ether (CH_3OCH_3) is one of the largest organic molecules detected in the interstellar medium. As an asymmetric top molecule with two methyl groups which undergo large amplitude motions and a dipole moment of μ=1.3 D, it conveys a dense spectrum throughout the terahertz region and contributes to the spectral line confusion in astronomical observations at these frequencies. In this paper, we present rotational spectra of dimethyl ether in its ground vibrational states, which have been measured in the laboratory and analyzed covering frequencies up to 2.1 THz. The analysis is based on an effective Hamiltonian for a symmetric two-top rotor and includes experimental data published so far. Frequency predictions are presented up to 2.5 THz for astronomical applications with accuracies better than 1 MHz. Table A.1 is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/504/635
NASA Technical Reports Server (NTRS)
Rudolph, H.; Mckoy, V.; Dixit, S. N.; Huo, W. M.
1988-01-01
Rotational branching ratios resulting from the (1 + 1) resonant enhanced multiphoton ionization spectroscopy of NO via the 0-0 transition of the A-X band for the four possible branches that can be assigned as R(21.5) are explored using calculation performed in the frozen-core approximation at the Hartree-Fock level. The four different branches, of which three are distinctly different in the perturbative limit, have rather different branching ratios. The mixed R12 + Q22(21.5) branch, which is not intense and has the lowest transition energy, appears to give the best agreement with experimental branching ratio for parallel detection. The agreement is less satisfactory for perpendicular detection. Neither the effect of finite-acceptance angle of the photoelectron detector nor high intensities can explain the discrepancy.
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.
NASA Astrophysics Data System (ADS)
Daly, Adam M.; Drouin, Brian J.; Groner, Peter; Yu, Shanshan; Pearson, John C.
2015-01-01
The pure rotational spectrum of mono-deuterated ethane, CH3CH2D, has been measured up to 1600 GHz and spectroscopic constants have been fit to 984 transitions in the ground state and 422 transitions in the first torsional excited state (ν18). Analyses of the ground state data were performed with the programs SPFIT, ERHAM and XIAM and of the first torsional state with SPFIT and ERHAM to extract molecular and spectroscopic constants. A combined fit of both states using ERHAM was used to determine ρ = 0.4344026(68), which in the symmetric limit is the ratio Iα/Iz and a measure of the periodicity of the internal rotation energy with K and the energy differences between the A and E torsional substates, ΔE(E-A), of 74.167(18) and -3382.23(34) MHz for the ground and excited states, respectively. Using these energy differences and the overtone transitions Δv = 2 from Raman measurements in the literature, the coefficients V3 and V6 of the potential function of the internal rotation in CH3CH2D were determined as V3 = 1004.56(4) cm-1 and V6 = 7.09(12) cm-1. This analysis lays the ground work for the assignment of the IR spectrum of CH3CH2D between (680-880 cm-1) which will help quantify isotopic ratios by remote sensing missions.
NASA Astrophysics Data System (ADS)
Felker, Peter M.
2014-11-01
The quantal translation-rotation (TR) states of the (p-H2)2@51264 clathrate hydrate inclusion compound have been computed. The ten-dimensional problem (in the rigid-cage and rigid-H2 approximation) is solved by first approximating the H2 moieties as spherically symmetric and solving for their 6D translational eigenstates. These are then combined with H2 free rotational states in a product basis that is used to diagonalize the full TR hamiltonian. The computed low-energy eigenstates have translational components that are essentially identical to the 6D translational eigenstates and rotational components that are 99.9% composed of rotationally unexcited H2 moieties. In other words, TR coupling is minimal for the low-energy states of the species. The low-energy level structure is found to be substantially more congested than that of the more tightly packed (p-H2)4@51264 clathrate species. The level structure is also shown to be understandable in terms of a model of (H2)2 as a semirigid diatomic species consisting of two spherically symmetric H2 pseudo-atoms.
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.
Emergence of frustrated antiferromagnet in the lowest Landau level
NASA Astrophysics Data System (ADS)
Rhim, Jun Won; Archer, Alexander C.; Jain, Jainendra K.; Park, Kwon; Condensed Matter Theory Collaboration
2014-03-01
We investigate the spin structure of the triangular composite fermion crystals (CFCs) in the lowest Landau level (LLL). In contrast to the usual Hund's rule, our Monte-Carlo (MC) calculation finds the spin exchange energy to be antiferromagnetic in certain parameter regimes in the vicinity of ν = 1 / 5 . For further physical intuition, we develop an effective two-body potential between composite fermions in the crystal phase, which provides a reasonable account of the MC results. We discuss the experimental feasibility of this physics.
Lowest order QED radiative corrections to longitudinally polarized Moeller scattering
Ilyichev, A.; Zykunov, V.
2005-08-01
The total lowest-order electromagnetic radiative corrections to the observables in Moeller scattering of longitudinally polarized electrons have been calculated. The final expressions obtained by the covariant method for the infrared divergency cancellation are free from any unphysical cut-off parameters. Since the calculation is carried out within the ultrarelativistic approximation our result has a compact form that is convenient for computing. Basing on these expressions the FORTRAN code MERA has been developed. Using this code the detailed numerical analysis performed under SLAC (E-158) and JLab kinematic conditions has shown that the radiative corrections are significant and rather sensitive to the value of the missing mass (inelasticity) cuts.
Dynamics of momentum entanglement in lowest-order QED
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.
NASA Astrophysics Data System (ADS)
Lu, Yongchuan; Wang, Chen
2016-07-01
We investigate the ground-state behavior of the Dicke-Hubbard model including counter-rotating terms. By generalizing an extended coherent-state approach within mean-field theory, we self-consistently obtain the ground-state energy and delocalized order parameter. Localization-delocalization quantum phase transition of photons is clearly observed by breaking the parity symmetry. Particularly, Mott lobes are fully suppressed, and the delocalized order parameter shows monotonic enhancement by increasing qubit-cavity coupling strength, in sharp contrast to the Dicke-Hubbard model under rotating-wave approximation. Moreover, the corresponding phase boundaries are stabilized by decreasing photon hopping strength, compared to the Rabi-Hubbard model.
NASA Astrophysics Data System (ADS)
Staelens, Steven; Vandenberghe, Stefaan; De Beenhouwer, Jan; De Clercq, Stijn; D'Asseler, Yves; Lemahieu, Ignace; Van de Walle, Rik
2004-05-01
The main goal of this work is to assess the overall imaging performance of dedicated new solid state devices compared to a traditional scintillation camera for use in SPECT imaging. A solid state detector with a rotating slat collimator will be compared with the same detector mounted with a classical collimator as opposed to a traditional Anger camera. A better energy resolution characterizes the solid state materials while the rotating slat collimator promises a better sensitivity-resolution tradeoff. The evaluation of the different imaging modalities is done using GATE, a recently developed Monte Carlo code. Several features for imaging performance evaluation were addressed: spatial resolution, energy resolution, sensitivity, and a ROC analysis was performed to evaluate the hot spot detectability. In this way a difference in perfromance was concluded for the diverse imaging techniques which allows a task dependent application of these modalities in future clinical practice.
Hot water emission spectra: Rotational energy levels of the (0 0 0) and (0 1 0) states of HD17O
NASA Astrophysics Data System (ADS)
Mellau, Georg Ch.; Mikhailenko, Semen N.; Tyuterev, Vladimir G.
2015-02-01
The rotational transitions of the HD17O water isotopologue have been assigned in a high temperature emission spectrum between 320 and 520 cm-1 of water vapor enriched by deuterium and 17O. We assigned 169 emission lines to 189 partly overlapping transitions of pure rotational and the ν2-ν2 rotational bands. A new extended set of 390 rotational energy levels for the (0 0 0) and (0 1 0) vibration states of HD17O up to J = 17 and Ka = 13 was obtained by combination of the new line transitions with those reported in previous studies. We constructed an effective rotational Hamiltonian based on the generation function approach. For this Hamiltonian the deviation between calculated and measured eigenenergies is in the order of 0.001 cm-1. We report a new calculated linelist based on our new energy level list. Our linelist supersedes the IUPAC linelist for the HD17O water isotopologue as it is based on a substantially extended set of accurate transition wavenumbers.
NASA Astrophysics Data System (ADS)
Groner, P.
2009-06-01
The rotational spectrum of methyl carbamate in the first excited torsional state (up to 149 GHz) has been analyzed recently for rotational quantum number J up to 20 together with transitions in the ground state. An extended analysis of the rotational spectrum in the ground state between 10 and 371 GHz with over 6000 transitions with J up to 60 has also been published. In the spectra recorded at that time by the FASSST method, about 3000 transitions belonging to the first torsional excited state of the methyl group have now been assigned and analyzed, about half of them belonging to the E torsional species. Both the newly assigned and previously published transitions have been used to fit less than 45 spectroscopic parameters of an effective rotational Hamiltonian for such systems, achieving a dimensionless standard deviation of 1.33. A somewhat unexpected result was the value of the {ρ} parameter of 0.063628(20) which differed significantly from the value obtained for the ground state of 0.058791(15). The discrepancy will be investigated in the near future. Hopefully, a resolution of the problem can be achieved by a combined fit of all excited and ground state transitions using common {ρ} and {β} parameters with {β} as the angle between the {ρ}-axis and the a principal axis. V. Ilyushin, E. Alekseev, J. Demaison, I. Kleiner, J. Mol. Spectrosc. 240, 127 (2006). P. Groner, M. Winnewisser, I. R. Medvedev, F. C. De Lucia, E. Herbst, K. V. L. N. Sastry, Astrophys. J. Suppl. Ser. 169, 28 (2007). P. Groner, J. Chem. Phys. 107, 4483 (1997).
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.
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.
Rationality, Irrationality and Escalating Behavior in Lowest Unique Bid Auctions
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
Bordbar, G. H.; Bigdeli, M.
2008-01-15
In this paper, we calculate properties of the spin polarized asymmetrical nuclear matter and neutron star matter, using the lowest order constrained variational (LOCV) method with the AV{sub 18}, Reid93, UV{sub 14}, and AV{sub 14} potentials. According to our results, the spontaneous phase transition to a ferromagnetic state in the asymmetrical nuclear matter as well as neutron star matter do not occur.
Lowest order constrained variational calculation of polarized neutron matter at finite temperature
Bordbar, G. H.; Bigdeli, M.
2008-11-15
Some properties of polarized neutron matter at finite temperature have been studied using the lowest order constrained variational (LOCV) method with the Argonne V18 (AV18) potential. Our results indicate that a spontaneous transition to the ferromagnetic phase does not occur. Effective mass, free energy, magnetic susceptibility, entropy, and the equation of state of polarized neutron matter at finite temperature are also calculated. A comparison is also made between our results and those of other many-body techniques.
Scintillation advantages of lowest order Bessel-Gaussian beams
NASA Astrophysics Data System (ADS)
Eyyuboğlu, H. T.; Baykal, Y.; Sermutlu, E.; Cai, Y.
2008-08-01
For a weak turbulence propagation environment, the scintillation index of the lowest order Bessel-Gaussian beams is formulated. Its triple and single integral versions are presented. Numerical evaluations show that at large source sizes and large width parameters, when compared at the same source size, Bessel-Gaussian beams tend to exhibit lower scintillations than the Gaussian beam scintillations. This advantage is lost however for excessively large width parameters and beyond certain propagation lengths. Large width parameters also cause rises and falls in the scintillation index of off-axis positions toward the edges of the received beam. Comparisons against the fundamental Gaussian beam are made on equal source size and equal power basis.
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.
NASA Astrophysics Data System (ADS)
Sironneau, V.; Chelin, P.; Tchana, F. Kwabia; Kleiner, I.; Pirali, O.; Roy, P.; Guillemin, J.-C.; Orphal, J.; Margulès, L.; Motiyenko, R. A.; Cooke, S. A.; Youngblood, W. J.; Agnew, A.; Dewberry, C. T.
2011-05-01
The first far-infrared high resolution absorption measurement of the cis-methyl nitrite molecule has been recorded in the range 15-400 cm -1 using the synchrotron AILES beamline radiation at SOLEIL with a resolution of 0.0011 cm -1. First assignments for the pure rotational transitions (15-65 cm -1) belonging to the ground ν t (= ν15) = 0 and first ν t = 1 excited torsional state are based on measurements from previous studies performed in the 13-40 GHz spectral range, as well as on new millimeter-wave measurements performed at Lille in the spectral range 75-465 GHz. A few measurements and remeasurements in the 1.8-13 GHz were also performed using the chirped FT-MW spectrometer located in North Texas. The pure rotational transitions in the far-infrared and in the microwave spectral range belonging to the two first torsional states have been globally fitted using the RAM ("Rho Axis Method") dealing with the rotation-torsion Hamiltonian and implemented in the BELGI code. A total of 708 and 713 microwave transitions (6 ⩽ J ⩽ 40, Kamax ⩽ 23) belonging to the ground torsional state ν t = 0 and 1 have been fitted with root-mean-square (rms) deviations of 37.4 kHz and 32.3 kHz respectively, and 3170 pure rotational transitions in the far-infrared range (12 ⩽ J max ⩽ 65, 0 ⩽ Kamax ⩽ 48) belonging to ν t = 0 and 1 have been fitted with a rms deviation of 0.00017 cm -1, using 35 parameters. Since in the far-infrared spectral range, the A-E internal rotor splittings have not been observed for the transitions belonging to the torsional ground ν t = 0 state of the cis-methyl nitrite species, another fit was performed on those lines, using a Watson type Hamiltonian for comparison.
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. PMID:14603714
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.âº Asteroid and...
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.
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.
Smarter than Others? Conjectures in Lowest Unique Bid Auctions
Hu, Rui; Chen, Qinghua
2015-01-01
Research concerning various types of auctions, such as English auctions, Dutch auctions, highest-price sealed-bid auctions, and second-price sealed-bid auctions, is always a topic of considerable interest in interdisciplinary fields. The type of auction, known as a lowest unique bid auction (LUBA), has also attracted significant attention. Various models have been proposed, but they often fail to explain satisfactorily the real bid-distribution characteristics. This paper discusses LUBA bid-distribution characteristics, including the inverted-J shape and the exponential decrease in the upper region. The authors note that this type of distribution, which initially increases and later decreases, cannot be derived from the symmetric Nash equilibrium framework based on perfect information that has previously been used. A novel optimization model based on non-perfect information is presented. The kernel of this model is the premise that agents make decisions to achieve maximum profit based on imaginary information or assumptions regarding the behavior of others. PMID:25849631
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 ND3 is described. In an apparatus recently constructed to study cold ion-molecule collisions, the ND3 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 ND3 can be produced with rotational state populations corresponding to approximately T(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 ND3. The translational temperature of the guided ND3 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. PMID:25028020
NASA Astrophysics Data System (ADS)
Brooke, James S. A.; Bernath, Peter F.; Western, Colin; Li, Gang; Groenenboom, Gerrit
2014-06-01
A new line list for rovibrational and rotational transitions within the NH X^3Σ{^-} ground state has been created, including line intensities in the form of Einstein A and f-values, for all possible bands up to v^'=6. The intensities are based on a new dipole moment function (DMF), which has been calculated using the internally contracted MRCI method with an aug-cc-pV6Z basis set. The programs RKR1, LEVEL and PGOPHER were used to calculate line positions and intensities using the most recent spectroscopic observations and the new DMF, and including the rotational dependence on the matrix elements. The Hund's case (b) matrix elements from the LEVEL output have been transformed to the case (a) form required by PGOPHER. Equivalent calculations have been performed for the OH X^2Π ground state. This includes a new DMF calculation using the internally contracted MR-ACPF method with an aug-cc-pV6Z basis set. A similar line list has been produced for rovibrational and rotational transitions for all possible transitions up to v^'=13.
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.
NASA Astrophysics Data System (ADS)
Lipus, K.; Simon, U.; Bachem, E.; Nelis, Th.; Urban, W.
We report the first direct observation of the vibration-rotation spectrum of nickel-deuteride in its X2Δ ground state by CO-Faraday-L.M.R. spectroscopy. A set of effective molecular parameters is given. We present first results on the vibration-rotation spectroscopy of NiH, employing a tunable diode laser spectrometer.
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. PMID:27083725
Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; Field, Robert W.
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
NASA Astrophysics Data System (ADS)
Park, G. Barratt; Jiang, Jun; Saladrigas, Catherine A.; Field, Robert W.
2016-04-01
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, 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 C ˜ electronic state.
LHC phenomenology of lowest massive Regge recurrences in the Randall-Sundrum orbifold
Anchordoqui, Luis A.; Huang Xing; Goldberg, Haim; Taylor, Tomasz R.
2010-11-15
We consider string realizations of the Randall-Sundrum effective theory for electroweak symmetry breaking and explore the search for the lowest massive Regge excitation of the gluon and of the extra (color singlet) gauge boson inherent in D-brane constructions. In these curved backgrounds, the higher-spin Regge recurrences of standard model fields localized near the IR brane are warped down to close to the TeV range and hence can be produced at collider experiments. Assuming that the theory is weakly coupled, we make use of four gauge boson amplitudes evaluated near the first Regge pole to determine the discovery potential of LHC. We study the inclusive dijet mass spectrum in the central rapidity region |y{sub jet}|<1.0 for dijet masses M{>=}2.5 TeV. We find that with an integrated luminosity of 100 fb{sup -1}, the 5{sigma} discovery reach can be as high as 4.7 TeV. Observations of resonant structures in pp{yields}direct{gamma}+jet can provide interesting corroboration for string physics up to 3.0 TeV. We also study the ratio of dijet mass spectra at small and large scattering angles. We show that with the first fb{sup -1} such a ratio can probe lowest-lying Regge states for masses {approx}2.5 TeV.
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.
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.
Improved calculations of the lowest vibrational transitions in HeH{sup +}
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)].
Sigma meson and lowest possible glueball candidate in an extended linear {sigma} model
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.
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.
NASA Astrophysics Data System (ADS)
Uberna, Radoslaw; Khalil, Munira; Williams, Richard M.; Papanikolas, John M.; Leone, Stephen R.
1998-06-01
Femtosecond laser pulse amplitude/phase masking techniques are employed to control the formation and detection of rotational wave packets in the electronic E 1Σg+ state of lithium dimer. The wave packets are prepared by coherent excitation of rovibronic E 1Σg+(νE,JE) states of Li2 from a single intermediate state, A 1Σu+(νA=11,JA=28), and probed by time-resolved photoionization. In the detection step, the wave packet is projected onto the X 2Σg+ state of Li2+. New resonance structure in the X 2Σu+ ionic state continuum is obtained by measuring the wave packet signal modulation amplitude as a function of the frequencies removed from the spectrally dispersed probe pulse by insertion of a wire mask in a single-grating pulse shaper. A split glass phase mask inserted into the pulse shaper is used to produce step function changes in the spectral phase of the pulse. The phase relation among the wave packet states is varied by changing the relative phases of spectral components in the pump pulse and is monitored by measuring the changes in the phase of the rotational wave packet recurrences using an unmodified probe pulse. By altering the relative phases among the wave packet components, the spatial distribution of the initial wave packet probability density is varied, resulting in phase-dependent "alignment" of the probability density in angular space. Phase changes in the signal recurrences are also observed when a phase modified pulse is used in the wave packet detection step after wave packet preparation with an unmodified pulse. The formation and detection of the wave packets is discussed in terms of quantum interference between different excitation routes. The relative phase factors encoded in a single optical pulse (pump or probe) are transferred into the interference term of the measured signal through the molecule-photon interaction.
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…
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. PMID:27544099
Jiang, Jun; Park, G. Barratt; Field, Robert W.
2016-04-14
A new quartic force field for the SO2 C~1B2 state has been derived, based on high resolution data from S16O2 and S18O2. Included are eight b2 symmetry vibrational levels of S16O2 reported in the first paper of this series [G. B. Park, et al., J. Chem. Phys. 144, 144311 (2016)]. Many of the experimental observables not included in the fit, such as the Franck-Condon intensities and the Coriolis-perturbed effective C rotational constants of highly anharmonic C~ state vibrational levels, are well reproduced using our force field. Because the two stretching modes of the C~ state are strongly coupled via Fermi-133more » interaction, the vibrational structure of the C state is analyzed in a Fermi-system basis set, constructed explicitly in this work via partial diagonalization of the vibrational Hamiltonian. The physical significance of the Fermi-system basis is discussed in terms of semiclassical dynamics, based on study of Fermi-resonance systems by Kellman and coworkers [M. E. Kellman and L. Xiao, J. Chem. Phys. 93, 5821 (1990)]. By diagonalizing the vibrational Hamiltonian in the Fermi-system basis, the vibrational characters of all vibrational levels can be determined unambiguously. It is shown that the bending mode cannot be treated separately from the coupled stretching modes, particularly at vibrational energies of more than 2000 cm–1. Based on our force field, the structure of the Coriolis interactions in the C~ state of SO2 is also discussed. As a result, we identify the origin of the alternating patterns in the effective C rotational constants of levels in the vibrational progressions of the symmetry-breaking mode, νβ (which correlates with the antisymmetric stretching mode in our assignment scheme).« less
Jiang, Jun; Park, G Barratt; Field, Robert W
2016-04-14
A new quartic force field for the SO2 C̃(1)B2 state has been derived, based on high resolution data from S(16)O2 and S(18)O2. Included are eight b2 symmetry vibrational levels of S(16)O2 reported in the first paper of this series [G. B. Park et al., J. Chem. Phys. 144, 144311 (2016)]. Many of the experimental observables not included in the fit, such as the Franck-Condon intensities and the Coriolis-perturbed effective C rotational constants of highly anharmonic C̃ state vibrational levels, are well reproduced using our force field. Because the two stretching modes of the C̃ state are strongly coupled via Fermi-133 interaction, the vibrational structure of the C̃ state is analyzed in a Fermi-system basis set, constructed explicitly in this work via partial diagonalization of the vibrational Hamiltonian. The physical significance of the Fermi-system basis is discussed in terms of semiclassical dynamics, based on study of Fermi-resonance systems by Kellman and Xiao [J. Chem. Phys. 93, 5821 (1990)]. By diagonalizing the vibrational Hamiltonian in the Fermi-system basis, the vibrational characters of all vibrational levels can be determined unambiguously. It is shown that the bending mode cannot be treated separately from the coupled stretching modes, particularly at vibrational energies of more than 2000 cm(-1). Based on our force field, the structure of the Coriolis interactions in the C̃ state of SO2 is also discussed. We identify the origin of the alternating patterns in the effective C rotational constants of levels in the vibrational progressions of the symmetry-breaking mode, νβ (which correlates with the antisymmetric stretching mode in our assignment scheme). PMID:27083726
NASA Astrophysics Data System (ADS)
Jiang, Jun; Park, G. Barratt; Field, Robert W.
2016-04-01
A new quartic force field for the SO2 C ˜ 1B2 state has been derived, based on high resolution data from S16O2 and S18O2. Included are eight b2 symmetry vibrational levels of S16O2 reported in the first paper of this series [G. B. Park et al., J. Chem. Phys. 144, 144311 (2016)]. Many of the experimental observables not included in the fit, such as the Franck-Condon intensities and the Coriolis-perturbed effective C rotational constants of highly anharmonic C ˜ state vibrational levels, are well reproduced using our force field. Because the two stretching modes of the C ˜ state are strongly coupled via Fermi-133 interaction, the vibrational structure of the C ˜ state is analyzed in a Fermi-system basis set, constructed explicitly in this work via partial diagonalization of the vibrational Hamiltonian. The physical significance of the Fermi-system basis is discussed in terms of semiclassical dynamics, based on study of Fermi-resonance systems by Kellman and Xiao [J. Chem. Phys. 93, 5821 (1990)]. By diagonalizing the vibrational Hamiltonian in the Fermi-system basis, the vibrational characters of all vibrational levels can be determined unambiguously. It is shown that the bending mode cannot be treated separately from the coupled stretching modes, particularly at vibrational energies of more than 2000 cm-1. Based on our force field, the structure of the Coriolis interactions in the C ˜ state of SO2 is also discussed. We identify the origin of the alternating patterns in the effective C rotational constants of levels in the vibrational progressions of the symmetry-breaking mode, νβ (which correlates with the antisymmetric stretching mode in our assignment scheme).
Krüger, Bastian C; Bartels, Nils; Wodtke, Alec M; Schäfer, Tim
2016-06-01
When NO molecules collide at a Au(111) surface, their interaction is controlled by several factors; especially important are the molecules' orientation with respect to the surface (N-first vs. O-first) and their distance of closest approach. In fact, the former may control the latter as N-first orientations are attractive and O-first orientations are repulsive. In this work, we employ electric fields to control the molecules' incidence orientation in combination with rotational rainbow scattering detection. Specifically, we report final rotational state distributions of oriented NO(vi = 11) molecules scattered from Au(111) for final vibrational states between vf = 4 and 11. For O-first collisions, the interaction potential is highly repulsive preventing the close approach and scattering results in high-J rainbows. By contrast, these rainbows are not seen for the more intimate collisions possible for attractive N-first orientations. In this way, we reveal the influence of orientation and the distance of closest approach on vibrational relaxation of NO(vi = 11) in collisions with a Au(111) surface. We also elucidate the influence of steering forces which cause the O-first oriented molecules to rotate to an N-first orientation during their approach to the surface. The experiments show that when NO collides at the surface with the N-atom first, on average more than half of the initial vibrational energy is lost; whereas O-first oriented collisions lose much less vibrational energy. These observations qualitatively confirm theoretical predictions of electronically non-adiabatic NO interactions at Au(111). PMID:27193070
NASA Astrophysics Data System (ADS)
Bang, Jeongho; Lee, Seung-Woo; Lee, Chang-Woo; Jeong, Hyunseok
2015-01-01
We propose a quantum algorithm to obtain the lowest eigenstate of any Hamiltonian simulated by a quantum computer. The proposed algorithm begins with an arbitrary initial state of the simulated system. A finite series of transforms is iteratively applied to the initial state assisted with an ancillary qubit. The fraction of the lowest eigenstate in the initial state is then amplified up to 1. We prove that our algorithm can faithfully work for any arbitrary Hamiltonian in the theoretical analysis. Numerical analyses are also carried out. We firstly provide a numerical proof-of-principle demonstration with a simple Hamiltonian in order to compare our scheme with the so-called "Demon-like algorithmic cooling (DLAC)", recently proposed in Xu (Nat Photonics 8:113, 2014). The result shows a good agreement with our theoretical analysis, exhibiting the comparable behavior to the best `cooling' with the DLAC method. We then consider a random Hamiltonian model for further analysis of our algorithm. By numerical simulations, we show that the total number of iterations is proportional to , where is the difference between the two lowest eigenvalues and is an error defined as the probability that the finally obtained system state is in an unexpected (i.e., not the lowest) eigenstate.
Exponential Decay of the Vorticity in the Steady-State Flow of a Viscous Liquid Past a Rotating Body
NASA Astrophysics Data System (ADS)
Deuring, Paul; Galdi, Giovanni P.
2016-07-01
Consider the flow of a Navier-Stokes liquid past a body rotating with a prescribed constant angular velocity, {ω}, and assume that the motion is steady with respect to a body-fixed frame. In this paper we show that the vorticity field associated to every "weak" solution corresponding to data of arbitrary "size" ( Leray Solution) must decay exponentially fast outside the wake region at sufficiently large distances from the body. Our result improves and generalizes in a non-trivial way famous results by Clark (Indiana Univ Math J 20:633-654, 1971) and Babenko and Vasil'ev (J Appl Math Mech 37:651-665, 1973) obtained in the case {ω=0}.
NASA Astrophysics Data System (ADS)
Jensen, Per; Buenker, Robert J.; Hirsch, Gerhard; Rai, Sachchida N.
We have calculated ab initio the three-dimensional potential-energy surface of the NH2 molecule at 145 nuclear geometries spanning energy ranges of about 18 000 cm-1 for the NH stretch and 12 000 cm-1 for the bend. The ab initio configuration-interaction calculations were done using the multireference MRD-CI method. The calculated equilibrium configuration has NH bond length re = 1·0207 Å and bond angle α = 103·1°. The rotational-vibrational energies for 14NH2, 14NHD and 14ND2 were calculated variationally using the Morse-oscillator rigid-bender internal-dynamics Hamiltonian. For 14NH2 we calculate that υ1 = 3267 (3219) cm-1, υ2 = 1462 (1497) cm-1 and υ3 = 3283 (3301) cm-1, where experimental values are given in parentheses.
NASA Astrophysics Data System (ADS)
Brooke, James S. A.; Bernath, Peter F.; Western, Colin M.
2015-07-01
Recently, a line list including positions and transition strengths was published for the NH X3Σ- rovibrational and rotational transitions. The calculation of the transition strengths requires a conversion of transition matrix elements from Hund's case (b) to (a). The method of this conversion has recently been improved during other work on the OH X2Π rovibrational transitions, by removing an approximation that was present previously. The adjusted method has been applied to the NH line list, resulting in more accurate transition strengths. An updated line list is presented that contains all possible transitions with v' and v″ up to 6, and J up to between 25 and 44, depending on the band.
Denis-Alpizar, Otoniel; Stoecklin, Thierry; Halvick, Philippe; Dubernet, Marie-Lise
2013-07-21
A four-dimensional potential energy surface representing the interaction between He and hydrogen cyanide (HCN) subjected to bending vibrational motion is presented. Ab initio calculations were carried out at the coupled-cluster level with single and double excitations and a perturbative treatment of triple excitations, using a quadruple-zeta basis set and mid-bond functions. The global minimum is found in the linear He-HCN configuration with the H atom pointing towards helium at the intermolecular separation of 7.94 a0. The corresponding well depth is 30.35 cm(-1). First, the quality of the new potential has been tested by performing two comparisons with previous theoretical and experimental works. (i) The rovibrational energy levels of the He-HCN complex for a rigid linear configuration of the HCN molecule have been calculated. The dissociation energy is 8.99 cm(-1), which is slightly smaller than the semi-empirical value of 9.42 cm(-1). The transitions frequencies are found to be in good agreement with the experimental data. (ii) We performed close coupling calculations of the rotational de-excitation of rigid linear HCN in collision with He and observed a close similarity with the theoretical data published in a recent study. Second, the effects of the vibrational bending of HCN have been investigated, both for the bound levels of the He-HCN system and for the rotationally inelastic cross sections. This was performed with an approximate method using the average of the interaction potential over the vibrational bending wavefunction. While this improves slightly the comparison of calculated transitions frequencies with experiment, the cross sections remain very close to those obtained with rigid linear HCN. PMID:23883024
NASA Technical Reports Server (NTRS)
Green, S.
1976-01-01
The formalism for describing rotational excitation in collisions between symmetric top rigid rotors and spherical atoms is presented both within the accurate quantum close coupling framework and also the coupled states approximation of McGuire and Kouri and the effective potential approximation of Rabitz. Calculations are reported for thermal energy NH3-He collisions, treating NH3 as a rigid rotor and employing a uniform electron gas (Gordon-Kim) approximation for the intermolecular potential. Coupled states are found to be in nearly quantitative agreement with close coupling results while the effective potential method is found to be at least qualitatively correct. Modifications necessary to treat the inversion motion in NH3 are discussed.
NASA Astrophysics Data System (ADS)
Schou, Jesper; Beck, John G.
2001-01-01
Simple convection models estimate the depth of supergranulation at approximately 15,000 km which suggests that supergranules should rotate at the rate of the plasma in the outer 2% of the Sun by radius. Previous measurements (Snodgrass & Ulrich, 1990; Beck & Schou, 2000) found that supergranules rotate significantly faster than this, with a size-dependent rotation rate. We expand on previous work and show that the torsional oscillation signal seen in the supergranules tracks that obtained for normal modes. We also find that the amplitudes and lifetimes of the supergranulation are size dependent.
Electronic structure with vibration-rotation study of the NaYb molecule
NASA Astrophysics Data System (ADS)
Tohme, Samir N.; Korek, Mahmoud
2015-10-01
The potential energy curves have been investigated for the 15 lowest doublet and quartet electronic states in the 2s+1Λ± representation of the molecule NaYb via CASSCF/MRCI (single and double excitations with Davidson correction) calculations. The spectroscopic constants (Te, De, ωe, Be, re, …) have been calculated in addition to the permanent dipole moments μ. By using the canonical functions approach, the eigenvalues Ev, the rotational constants Bv, the centrifugal distortion constant Dv, and the abscissas of the turning points rmin and rmax have been calculated for different electronic states. Fourteen molecular states have been studied theoretically for the first time.
NASA Astrophysics Data System (ADS)
Dziembowski, W.
Sunspot observations made by Johannes Hevelius in 1642 - 1644 are the first ones providing significant information about the solar differential rotation. In modern astronomy the determination of the rotation rate is done in a routine way by measuring positions of various structures on the solar surface as well as by studying the Doppler shifts of spectral lines. In recent years a progress in helioseismology enabled determination of the rotation rate in the layers inaccessible for direct observations. There are still uncertainties concerning, especially, the temporal variations of the rotation rate and its behaviour in the radiative interior. We are far from understanding the observations. Theoretical works have not yet resulted in a satisfactory model for the angular momentum transport in the convective zone.
NASA Astrophysics Data System (ADS)
Fletcher, N. H.; Tarnopolsky, A. Z.; Lai, J. C. S.
2002-03-01
Free rotational aerophones such as the bullroarer, which consists of a wooden slat whirled around on the end of a string, and which emits a loud pulsating roar, have been used in many ancient and traditional societies for ceremonial purposes. This article presents an experimental and theoretical investigation of this instrument. The aerodynamics of rotational behavior is elucidated, and relates slat rotation frequency to slat width and velocity through the air. Analysis shows that sound production is due to generation of an oscillating-rotating dipole across the slat, the role of the vortices shed by the slat being relatively minor. Apparent discrepancies between the behavior of a bullroarer slat and a slat mounted on an axle in a wind tunnel are shown to be due to viscous friction in the bearings of the wind-tunnel experiment.
Intrinsic rotation with gyrokinetic models
Parra, Felix I.; Barnes, Michael; Catto, Peter J.; Calvo, Ivan
2012-05-15
The generation of intrinsic rotation by turbulence and neoclassical effects in tokamaks is considered. To obtain the complex dependences observed in experiments, it is necessary to have a model of the radial flux of momentum that redistributes the momentum within the tokamak in the absence of a preexisting velocity. When the lowest order gyrokinetic formulation is used, a symmetry of the model precludes this possibility, making small effects in the gyroradius over scale length expansion necessary. These effects that are usually small become important for momentum transport because the symmetry of the lowest order gyrokinetic formulation leads to the cancellation of the lowest order momentum flux. The accuracy to which the gyrokinetic equation needs to be obtained to retain all the physically relevant effects is discussed.
A global search for the lowest energy isomer of C26
NASA Astrophysics Data System (ADS)
An, Jie; Gan, Li-Hua; Zhao, Jian-Qiang; Li, Rui
2010-04-01
The complete set of 2333 isomers of C26 fullerene composed of square, pentagonal, hexagonal, and heptagonal faces together with some noncage structures is investigated at the Hartree-Fock and density functional theory (DFT) levels. For the singlet states, a nonclassical isomer C26-10-01 with a square embedded is predicted by the DFT method as the lowest energy isomer, followed by the sole classical isomer C26-00-01. Further explorations reveal that the electronic ground state of C26-10-01 is triplet state in Cs symmetry, while that of C26-00-01 corresponds to its quintet in D3h symmetry. Both the total energies and nucleus independent chemical shift values at DFT level favor the classical isomer. It is found that both C26-00-01 and C26-10-01 possess high vertical electron affinity. The addition of electron(s) to C26-10-01 increases its aromatic character and encapsulation of Li atom into this cage is highly exothermic, indicating that it may be captured in the form of derivatives. To clarify the relative stabilities at elevated temperatures, the entropy contributions are taken into account based on the Gibbs free energy at the B3LYP/6-311+G∗ level. C26-10-01 behaves thermodynamically more stable than the classical isomer over a wide range of temperatures related to fullerene formation. The IR spectra of these two lowest energy isomers are simulated to facilitate their experimental identification.
NASA Astrophysics Data System (ADS)
Belcher, David E.; Watkins, Mark J.; Tonge, Nicola; Cockett, Martin C. R.
2004-05-01
The 1,4-diazabicyclo[2.2.2]octane-Arn (n=1,2,3) van der Waals complexes (DABCO-Arn) have been investigated using a combination of (1+1') resonance enhanced multiphoton ionization (REMPI) and zero electron kinetic energy (ZEKE) spectroscopy. The additivity of the spectral shifts observed in both REMPI and ZEKE spectra, taken together with analysis of vibrational structure, suggest that in both DABCO-Ar and DABCO-Ar2 the argon atoms bind in equivalent equatorial (face) locations between two adjacent (CH2)2 bridges. However, the cumulative evidence from both REMPI and ZEKE spectra, together with ab initio results, suggests that the DABCO-Ar3 complex does not revert to D3h symmetry, but rather adopts a C2v structure in which all three argon atoms bind to one side of the DABCO framework. The exceptionally low wave-number vibrational structure observed in the REMPI spectra suggest that the van der Waals interaction in the excited state is extremely weak. However, ionization necessarily increases the strength of the interaction by virtue of the introduction of charge-induced dipole forces, as revealed by a consistent increase in vibrational wave numbers of the modes observed in the resultant ZEKE spectra.
Bose-Einstein condensate in a rapidly rotating nonsymmetric trap
Fetter, Alexander L.
2010-03-15
A rapidly rotating Bose-Einstein condensate in a symmetric two-dimensional harmonic trap can be described with the lowest Landau-level set of single-particle states. The condensate wave function {psi}(x,y) is a Gaussian {proportional_to}exp(-r{sup 2}/2), multiplied by an analytic function f(z) of the complex variable z=x+iy. The criterion for a quantum phase transition to a non-superfluid correlated many-body state is usually expressed in terms of the ratio of the number of particles to the number of vortices. Here a similar description applies to a rapidly rotating nonsymmetric two-dimensional trap with arbitrary quadratic anisotropy ({omega}{sub x}{sup 2}<{omega}{sub y}{sup 2}). The corresponding condensate wave function {psi}(x,y) is a complex anisotropic Gaussian with a phase proportional to xy, multiplied by an analytic function f(z), where z=x+i{beta}{sub -}y is a stretched complex variable and 0{<=}{beta}{sub -{<=}}1 is a real parameter that depends on the trap anisotropy and the rotation frequency. Both in the mean-field Thomas-Fermi approximation and in the mean-field lowest Landau level approximation with many visible vortices, an anisotropic parabolic density profile minimizes the energy. An elongated condensate grows along the soft trap direction yet ultimately shrinks along the tight trap direction. The criterion for the quantum phase transition to a correlated state is generalized (1) in terms of N/L{sub z}, which suggests that a nonsymmetric trap should make it easier to observe this transition, or (2) in terms of a 'fragmented' correlated state, which suggests that a nonsymmetric trap should make it harder to observe this transition. An alternative scenario involves a crossover to a quasi one-dimensional condensate without visible vortices, as suggested by Aftalion et al., Phys. Rev. A 79, 011603(R) (2009).
Govor, L. I. Demidov, A. M.; Kurkin, V. A.; Mikhailov, I. V.
2015-03-15
Various reasons for the absence of rotational levels for J{sup π}K = 0{sup +}0{sub 2} and 2{sup +}2{sub 2} nonrotational states in {sup 164}Dy and {sup 166}Er are considered. Preference is given to the effect of the excitation of an anharmonic two-phonon state in pair vibrations of the superconducting type.
Noncommutative Chern-Simons theory and exotic geometry emerging from the lowest Landau level
NASA Astrophysics Data System (ADS)
Luo, Xi; Wu, Yong-Shi; Yu, Yue
2016-06-01
We relate the collective dynamic internal geometric degrees of freedom to the gauge fluctuations in ν =1 /m (m odd ) fractional quantum Hall effects. In this way, in the lowest Landau level, a highly nontrivial quantum geometry in two-dimensional guiding center space emerges from these internal geometric modes. Using the Dirac bracket method, we find that this quantum geometric field theory is a topological noncommutative Chern-Simons theory. Topological indices, such as the guiding center angular momentum (also called the shift) and the guiding center spin, which characterize the fractional quantum Hall (FQH) states besides the filling factor, are naturally defined. A noncommutative K-matrix Chern-Simons theory is proposed as a generalization to a large class of Abelian FQH topological orders.
The spatial and temporal variability of 03 concentrations over the eastern United States during the period of 1985 through 1990 was examined through the use of a multivariate statistical technique called Principal Component Analysis. he original data set, which contained 77 corre...
NASA Astrophysics Data System (ADS)
Lattanzi, Franca; di Lauro, Carlo; Horneman, Veli-Matti
2011-10-01
A high resolution Fourier transform infrared spectrum of C2H6, measured at a pressure of 173.3 Pa and an optical path of 153.2 m, was analysed between 1050 and 1295 cm-1. Extensive absorption due to the difference bands ν 11-ν 4, and several rotation-torsion lines of the difference band ν 2-ν 4, in the region of the x, y-Coriolis resonance of ν 2 and ν 11, were observed. This allowed a detailed rotation-torsion analysis of the upper states ν 11 and ν 2. The anomalous torsional structure, found in the non-degenerate vibrational state ν 2, can be explained as the effect of an Hamiltonian term accounting for a strong dependence of the torsional barrier height on the normal vibrational coordinate q 2. The value of the barrier height derivative ? is estimated to be 127 ± 10 cm-1. Also detected and assigned were 'hot' difference transitions belonging to the (ν 4 + ν 11)-2ν 4 band, yielding information on the upper state ν 4 + ν 11. It is believed that transitions from 3ν 4 to 2ν 4 + ν 11 are also detectable in the investigated region.
NASA Technical Reports Server (NTRS)
Dickey, Jean O.
1995-01-01
The study of the Earth's rotation in space (encompassing Universal Time (UT1), length of day, polar motion, and the phenomena of precession and nutation) addresses the complex nature of Earth orientation changes, the mechanisms of excitation of these changes and their geophysical implications in a broad variety of areas. In the absence of internal sources of energy or interactions with astronomical objects, the Earth would move as a rigid body with its various parts (the crust, mantle, inner and outer cores, atmosphere and oceans) rotating together at a constant fixed rate. In reality, the world is considerably more complicated, as is schematically illustrated. The rotation rate of the Earth's crust is not constant, but exhibits complicated fluctuations in speed amounting to several parts in 10(exp 8) [corresponding to a variation of several milliseconds (ms) in the Length Of the Day (LOD) and about one part in 10(exp 6) in the orientation of the rotation axis relative to the solid Earth's axis of figure (polar motion). These changes occur over a broad spectrum of time scales, ranging from hours to centuries and longer, reflecting the fact that they are produced by a wide variety of geophysical and astronomical processes. Geodetic observations of Earth rotation changes thus provide insights into the geophysical processes illustrated, which are often difficult to obtain by other means. In addition, these measurements are required for engineering purposes. Theoretical studies of Earth rotation variations are based on the application of Euler's dynamical equations to the problem of finding the response of slightly deformable solid Earth to variety of surface and internal stresses.
NASA Technical Reports Server (NTRS)
1979-01-01
In aircraft turbine engine research, certain investigations require extremely precise measurement of the position of a rotating part, such as the rotor, a disc-like part of the engine's compressor which revolves around a shaft at extremely high speeds. For example, in studies of airflow velocity within a compressor, researchers need to know-for data correlation the instantaneous position of a given spot on the rotor each time a velocity measurement is made. Earlier methods of measuring rotor shaft angle required a physical connection to the shaft, which limited the velocity of the rotating object.
NASA Astrophysics Data System (ADS)
Beyer, Maximilian; Merkt, Frédéric
2016-03-01
Although the existence of quasibound rotational levels of the X+ 2Σg+ ground state of H2+ was predicted a long time ago, these states have never been observed. Calculated positions and widths of quasibound rotational levels located close to the top of the centrifugal barriers have not been reported either. Given the role that such states play in the recombination of H (1 s ) and H+ to form H2+, this lack of data may be regarded as one of the largest unknown aspects of this otherwise accurately known fundamental molecular cation. We present measurements of the positions and widths of the lowest-lying quasibound rotational levels of H2+ and compare the experimental results with the positions and widths we calculate using a potential model for the X+ state of H2+ which includes adiabatic, nonadiabatic, relativistic, and radiative corrections to the Born-Oppenheimer approximation.
Brouard, M; Chadwick, H; Gordon, S D S; Hornung, B; Nichols, B; Kłos, J; Aoiz, F J; Stolte, S
2014-10-28
Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial Λ-doublet state selection is achieved using an inhomogeneous hexapole electric field. Differential cross sections and even-moment polarization dependent differential cross sections have been obtained at a collision energy of 514 cm(-1) for both spin-orbit and parity conserving and changing collisions. Experimental results are compared with those obtained from quantum scattering calculations and are shown to be in very good agreement. Hard shell quantum scattering calculations are also performed to determine the effects of the different parts of the potential on the scattering dynamics. Comparisons are also made with the NO(X) + Ar system. PMID:25362298
Brouard, M. Chadwick, H.; Gordon, S. D. S.; Hornung, B.; Nichols, B.; Kłos, J.; Aoiz, F. J.; Stolte, S.
2014-10-28
Fully quantum state selected and resolved inelastic scattering of NO(X) by krypton has been investigated. Initial Λ-doublet state selection is achieved using an inhomogeneous hexapole electric field. Differential cross sections and even-moment polarization dependent differential cross sections have been obtained at a collision energy of 514 cm{sup −1} for both spin-orbit and parity conserving and changing collisions. Experimental results are compared with those obtained from quantum scattering calculations and are shown to be in very good agreement. Hard shell quantum scattering calculations are also performed to determine the effects of the different parts of the potential on the scattering dynamics. Comparisons are also made with the NO(X) + Ar system.
Pair truncation for rotational nuclei: j=(17/2 model
NASA Astrophysics Data System (ADS)
Halse, P.; Jaqua, L.; Barrett, B. R.
1989-08-01
The suitability of the pair condensate approach for rotational states is studied in a single j=(17/2 shell of identical nucleons interacting through a quadrupole-quadrupole Hamiltonian. The ground band and a K=2 excited band are both studied in detail. A direct comparison of the exact states with those constituting the SD and SDG subspaces is used to identify the important degrees of freedom for these levels. The range of pairs necessary for a good description is found to be highly state dependent; S and D pairs are the major constituents of the low-spin ground-band levels, while G pairs are needed for those in the γ band. Energy spectra are obtained for each truncated subspace. SDG pairs allow accurate reproduction of the binding energy and K=2 excitation energy, but still give a moment of inertia which is about 30% too small even for the lowest levels.
Technology Transfer Automated Retrieval System (TEKTRAN)
Crop rotations have been a part of civilization since the Middle Ages. With colonization of what would become the United States came new crops of tobacco, cotton, and corn, the first two of which would play significant roles in both the economic beginnings and social fabric of the new country, how ...
NASA Astrophysics Data System (ADS)
Stuhlmann, Benjamin; Gmerek, Felix; Krügler, Daniel; Schmitt, Michael
2014-08-01
Single vibronic level fluorescence spectra of the electronic origin and of seven vibronic bands between 0,0 and 0,0 + 1265 cm-1 have been measured and analyzed by means of a combined Franck-Condon/rotational constants fit. The rotational constants in ground and lowest electronically excited singlet state of four different isotopologues have been taken from previous rotationally resolved measurements of Schmitt et al. (2006). The intensities of 182 vibronic emission bands and of 8 rotational constants have been used for a fit of the complete heavy atom geometry changes upon electronic excitation. Vibronic modes, about 1000 cm-1 above the electronic origin, show strong deviations from Franck-Condon behavior in emission. Herzberg-Teller coupling contributes to this effect. 1300 cm-1 above the origin, we observe the onset of intramolecular vibrational redistribution in the emission spectra.
Geometry of Landau Level without Galilean or Rotational Symmetry
NASA Astrophysics Data System (ADS)
Shen, Yu; Haldane, F. D. M.
The integer quantum Hall effect is usually modeled using Galilean-invariant or rotationally-invariant Landau levels. However, these are not generic symmetries of electrons moving in a crystalline background. We explicitly break both symmetries by considering a inversion-symmetric Hamiltonian with quartic terms. We carry out exact diagonalization numerically with a truncated Hilbert space, and define an emergent metric gabn for each Landau level as the expectation value of a bilinear form in momentum. With an appropriate choice of the guiding center coherent state, the Landau level wavefunctions are holomorphic functions of z* times a Gaussian (this is distinct from a well-known property of rotationally-invariant lowest-Landau-level wavefunctions). We show that the zeroes of the wavefunction define a ``topological spin sn'', with its original definition as an ``intrinsic angular momentum'' no longer valid without rotational symmetry. This is now related to the number of zeroes n encircled by the classical orbit by sn = n +1/2 . Finally we introduce a mass tensor mabn for each Landau level using a Lagrangian formalism. We conclude that topological and geometric information can be extracted without resort to Galilean or Rotational symmetries. This work is partly supported by DOE Grant No. DE-SC0002140 and the W. M. Keck Foundation.
Limão-Vieira, P; Duflot, D; Ferreira da Silva, F; Lange, E; Jones, N C; Hoffmann, S V; Śmiałek, M A; Jones, D B; Brunger, M J
2016-07-21
We present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3-10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional theory and the equation-of-motion coupled cluster method restricted to single and double excitations level. These have been used in the assignment of valence and Rydberg transitions of the phenol molecule. The VUV spectrum reveals several new features not previously reported in the literature, with particular reference to the 6.401 eV transition, which is here assigned to the 3sσ/σ(∗)(OH)←3π(3a″) transition. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of phenol in the earth's atmosphere (0-50 km). PMID:27448882
NASA Astrophysics Data System (ADS)
Limão-Vieira, P.; Duflot, D.; Ferreira da Silva, F.; Lange, E.; Jones, N. C.; Hoffmann, S. V.; Śmiałek, M. A.; Jones, D. B.; Brunger, M. J.
2016-07-01
We present the experimental high-resolution vacuum ultraviolet (VUV) photoabsorption spectra of phenol covering for the first time the full 4.3-10.8 eV energy-range, with absolute cross sections determined. Theoretical calculations on the vertical excitation energies and oscillator strengths were performed using time-dependent density functional theory and the equation-of-motion coupled cluster method restricted to single and double excitations level. These have been used in the assignment of valence and Rydberg transitions of the phenol molecule. The VUV spectrum reveals several new features not previously reported in the literature, with particular reference to the 6.401 eV transition, which is here assigned to the 3sσ/σ∗(OH)←3π(3a″) transition. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of phenol in the earth's atmosphere (0-50 km).
Magnetic ground state and spin fluctuations in MnGe chiral magnet as studied by muon spin rotation
NASA Astrophysics Data System (ADS)
Martin, N.; Deutsch, M.; Bert, F.; Andreica, D.; Amato, A.; Bonfà, P.; De Renzi, R.; Rößler, U. K.; Bonville, P.; Fomicheva, L. N.; Tsvyashchenko, A. V.; Mirebeau, I.
2016-05-01
We have studied by muon spin resonance (μ SR ) the helical ground state and fluctuating chiral phase recently observed in the MnGe chiral magnet. At low temperature, the muon polarization shows double-period oscillations at short-time scales. Their analysis, akin to that recently developed for MnSi [A. Amato et al., Phys. Rev. B 89, 184425 (2014), 10.1103/PhysRevB.89.184425], provides an estimation of the field distribution induced by the Mn helical order at the muon site. The refined muon position agrees nicely with ab initio calculations. With increasing temperature, an inhomogeneous fluctuating chiral phase sets in, characterized by two well-separated frequency ranges which coexist in the sample. Rapid and slow fluctuations, respectively, associated with short-range and long-range ordered helices, coexist in a large temperature range below TN=170 K. We discuss the results with respect to MnSi, taking the short helical period, metastable quenched state, and peculiar band structure of MnGe into account.
Was the drought of 2015 on the River Vistula in Warsaw the lowest ever observed?
NASA Astrophysics Data System (ADS)
Kowalski, Hubert; Magnuszewski, Artur; Romanowicz, Renata
2016-04-01
The River Vistula has a hydrological regime controlled by rainfall and snowmelt. The flood of 22 V 2010 r. had the highest discharge ever measured in Warsaw (Q=5898 m3/s). After this flood extreme low flows occurred in 12 IX 2012 (Q=172 m3/s) and in 28 VIII 2015 (157 m3/s). The low flow of 2015 set the lowest stage record (H=42 cm). The conditions during the low flow were favourable for archaeologists working on the River Vistula channel and banks. A group of archaeologists from the University of Warsaw discovered in the middle of the channel at 517 km a treasury of 17 century marbles and other finds. In 1656 Poland was in the state of war with Sweden. Marble sculptures were stolen and evacuated by the Swedish army from Warsaw to Gdansk harbor down the River Vistula. The barge transporting marbles sunk, leaving the treasure in the channel of the River Vistula. Since that time until now, the water levels in the river were too high to discover the treasures. The question is whether the drought of 2015 was the lowest in history and to what extent the lowest ever observed stage is related to the process of channel erosion in a regulated reach of the river. The specific conditions at the archaeological site have been studied using both long term hydrological data and hydrodynamic the 2D model CCHE2D, to the estimate erosion rate and velocities. The results show that the bottom erosion is quite strong and has caused lowering of the river bottom by 205 cm since 1919 (first rating curve published). The River Vistula reach in Warsaw forms a narrowing, called a "corset" which is controlled by the geological structures (river over flood terraces and glacial sills). Additionally the channel has been regulated by hydrotechnical structures and dredging work. The sequence of the 2010 year flood that increased the erosion rate in the reach and two deep low flows in 2012 and 2015 were favourable for archaeologists working in Warsaw on the River Vistula. The hydraulic conditions
Lafferty, Walter; Flaud, Jean-marie; Sams, Robert L.; Ngom, El Hadji A.
2008-11-01
A high resolution (0.0018 cm-1) Fourier transform instrument has been used to record the spectrum of an enriched 34S (95.3 %) sample of sulfur dioxide. A thorough analysis of the ν2, 2ν2 - ν2 , ν1, ν1 + ν2 - ν2, ν3, ν2 + ν3 - ν2, ν1 + ν2 and ν2 + ν3 bands has been carried out leading to a large set of assigned lines. From these lines ground state combination differences were obtained and fitted together with the existing microwave, millimeter, and terahertz rotational lines. An improved set of ground state rotational constants were obtained. Next, the upper state rotational levels were fitted. For the (010), (110), (011) states, a simple Watson type Hamilton sufficed. However, it was necessary to include explicitly interacting terms in the Hamiltonian matrix in order to fit the rotational levels of the (020), (100) and (101) states to within their experimental accuracy. More explicitly, it was necessary to use a ΔK=2 term to model the Fermi interaction between the (020) and (100) levels and a ΔK=3 term to model the Coriolis interaction between the (100) and (001) levels. Precise Hamiltonian constants were derived for the (000), (010), (100), (001), (020), (110) and (011) vibrational states.
Honma, Kenji; Miyashita, Kazuki; Matsumoto, Yoshiteru
2014-06-01
Oxidation reaction of a gas-phase aluminum atom by a molecular oxygen was studied by a crossed-beam condition at 12.4 kJ/mol of collision energy. A (1+1) resonance-enhanced multiphoton ionization (REMPI) via the D(2)Σ(+)-X(2)Σ(+) transition of AlO was applied to ionize the product. The REMPI spectrum was analyzed to determine rotational state distributions for v = 0-2 of AlO. For several vib-rotational states of AlO, state selected angular and kinetic energy distributions were determined by a time-sliced ion imaging technique for the first time. Kinetic energy distributions were well represented by that taken into account initial energy spreads of collision energy and the population of the spin-orbit levels of the counter product O((3)P(J)) determined previously. All angular distributions showed forward and backward peaks, and the forward peaks were more pronounced than the backward one for the states of low internal energy. The backward peak intensity became comparable to the forward one for the states of high internal energy. These results and the rotational state distributions suggested that the reaction proceeds via an intermediate which has a lifetime comparable to or shorter than its rotational period. PMID:24908005
NASA Astrophysics Data System (ADS)
Honma, Kenji; Miyashita, Kazuki; Matsumoto, Yoshiteru
2014-06-01
Oxidation reaction of a gas-phase aluminum atom by a molecular oxygen was studied by a crossed-beam condition at 12.4 kJ/mol of collision energy. A (1+1) resonance-enhanced multiphoton ionization (REMPI) via the D2Σ+-X2Σ+ transition of AlO was applied to ionize the product. The REMPI spectrum was analyzed to determine rotational state distributions for v = 0-2 of AlO. For several vib-rotational states of AlO, state selected angular and kinetic energy distributions were determined by a time-sliced ion imaging technique for the first time. Kinetic energy distributions were well represented by that taken into account initial energy spreads of collision energy and the population of the spin-orbit levels of the counter product O(3PJ) determined previously. All angular distributions showed forward and backward peaks, and the forward peaks were more pronounced than the backward one for the states of low internal energy. The backward peak intensity became comparable to the forward one for the states of high internal energy. These results and the rotational state distributions suggested that the reaction proceeds via an intermediate which has a lifetime comparable to or shorter than its rotational period.
carlomat: A program for automatic computation of lowest order cross sections
NASA Astrophysics Data System (ADS)
Kołodziej, Karol
2009-09-01
The current version of carlomat, a program for automatic computation of the lowest order cross sections of multiparticle reactions, is described. The program can be used as the Monte Carlo generator of unweighted events as well. Program summaryProgram title:carlomat Catalogue identifier: AEDQ_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDQ_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 101 613 No. of bytes in distributed program, including test data, etc.: 1 092 251 Distribution format: tar.gz Programming language: Fortran 90/95 Computer: all Operating system: Linux Classification: 4.4, 11.2 Nature of problem: Description of two particle scattering reactions with possibly up to 10 particles in the final state with a complete set of the Feynman diagrams in the lowest order of the Standard Model. Solution method: The matrix element for a user specified process and phase space parametrizations, which are necessary for the multichannel Monte Carlo integration of the lowest order cross sections and event generation, are generated automatically. Both the electroweak and quantum chromodynamics lowest order contributions are taken into account. Particle masses are not neglected in the program. Matrix elements are calculated numerically with the helicity amplitude method. Constant widths of unstable particles are implemented by modifying mass parameters in corresponding propagators. Restrictions: The number of external particles is limited to 12. Only the Standard Model is implemented at the moment in the program. No higher order effects are taken into account, except for assuming the fine structure constant and the strong coupling at appropriate scale and partial summation of the one particle irreducible loop corrections by introducing fixed widths of
Solid-state ring laser gyro behaving like its helium-neon counterpart at low rotation rates.
Schwartz, Sylvain; Gutty, François; Feugnet, Gilles; Loil, Eric; Pocholle, Jean-Paul
2009-12-15
Nonlinear couplings induced by crystal diffusion and spatial inhomogeneities of the gain have been suppressed over a broad range of angular velocities in a solid-state ring laser gyro by vibrating the gain crystal at 168 kHz and 0.4 microm along the laser cavity axis. This device behaves in the same way as a typical helium-neon ring laser gyro, with a zone of frequency lock-in (or dead band) resulting from the backscattering of light on the cavity mirrors. Furthermore, it is shown that the level of angular random-walk noise in the presence of mechanical dithering depends only on the quality of the cavity mirrors, as is the case with typical helium-neon ring laser gyros. PMID:20016646
Wilcox, S.; Andreas, A.
2012-11-03
The U.S. Department of Energy's National Renewable Energy Laboratory collaborates with the solar industry to establish high quality solar and meteorological measurements. This Solar Resource and Meteorological Assessment Project (SOLRMAP) provides high quality measurements to support deployment of power projects in the United States. The no-funds-exchanged collaboration brings NREL solar resource assessment expertise together with industry needs for measurements. The end result is high quality data sets to support the financing, design, and monitoring of large scale solar power projects for industry in addition to research-quality data for NREL model development. NREL provides consultation for instrumentation and station deployment, along with instrument calibrations, data acquisition, quality assessment, data distribution, and summary reports. Industry participants provide equipment, infrastructure, and station maintenance.
NASA Astrophysics Data System (ADS)
Müller, Holger S. P.; Ordu, Matthias H.; Lewen, Frank; Brown, Linda; Drouin, Brian; Pearson, John; Sung, Keeyoon; Kleiner, Isabelle; Sams, Robert
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 2ν_8 around 717~cm-1 with assignments covering 684-765~cm-1. Additional spectra in the ν _8 region were used to validate the analysis. Using ν _8 data as well as spectroscopic parameters for v_4 = 1, v_7 = 1, and v_8 = 3 from previous studies, we analyzed rotational data involving v = 0, v_8 = 1, and v_8 = 2 up to high J and K quantum numbers. We analyzed a strong Δ v_8 = ± 1, Δ K = 0, Δ l = ±3 Fermi resonance between v_8 = 1-1 and v_8 = 2+2 at K = 14 and obtained preliminary results for two further Fermi resonances between v_8 = 2 and 3. We also found resonant Δ v_8 = ± 1, Δ K = ∓ 2, Δ l = ± 1 interactions between v_8 = 1 and 2 and present the first detailed analysis of such a resonance between v_8 = 0 and 1. We discuss the impact of this analysis on the v_8 = 1 and 2 as well as on the axial v = 0 parameters and compare selected CH_3CN parameters with those of CH_3CCH and CH_3NC. We evaluated transition dipole moments of ν _8, 2ν _8 - ν _8, and 2ν _8 for remote sensing in the IR. Part of this work was carried out at the Jet Propulsion Laboratory under contract with the National Aeronautics and Space Administration. M. Koivusaari et al., J. Mol. Spectrosc. 152 (1992) 377-388. A.-M. Tolonen et al., J. Mol. Spectrosc. 160 (1993) 554-565.
Lowest l=0 proton resonance in {sup 26}Si and implications for nucleosynthesis of {sup 26}Al
Peplowski, P. N.; Baby, L. T.; Wiedenhoever, I.; Diffenderfer, E.; Hoeflich, P.; Rojas, A.; Volya, A.; Dekat, S. E.; Gay, D. L.; Grubor-Urosevic, O.; Kaye, R. A.; Keeley, N.
2009-03-15
Using a beam of the radioactive isotope {sup 25}Al, produced with the new RESOLUT facility, we measured the direct (d,n) proton-transfer reaction leading to low-lying proton resonances in {sup 26}Si. We observed the lowest l=0 proton resonance, identified with the 3{sup +} state at 5.914-MeV excitation energy. This result eliminates the largest uncertainty in astrophysical reaction rates involved in the nucleosynthesis of {sup 26}Al.
NASA Astrophysics Data System (ADS)
Harder, Hauke; Macholl, Sven; Mäder, Heinrich; Fusina, Luciano; Ozier, Irving
2010-03-01
For the principal isotopologue N14S32F193 of thiazyl trifluoride in the degenerate fundamental state (v5=1), the hyperfine structure has been investigated in the Q-branch spectrum between 8 and 26.5 GHz using microwave Fourier transform waveguide spectrometers with a resolution limit of ≈30 kHz. In addition to l-type doubling spectra and l-type resonance transitions with (Δk=Δl=±2), perturbation-allowed spectra were measured with Δ(k-l)=±3,±6. The range in J was from 13 to 61; for the lower states, kl=-3,-2,-1,0,+1. For all the transitions, the hyperfine patterns observed are predicted to be doublets when only the nitrogen quadrupole Hamiltonian HQN is taken into account. Doublets were indeed measured for transitions with ΓRV=A1↔A2, where ΓRV is the rovibrational symmetry. However, when ΓRV=E↔E, triplets and quartets were observed in addition to doublets. These anomalous hyperfine patterns are shown to be due to the (Δk=±1) and (Δk=±2) matrix elements of the fluorine spin-rotation Hamiltonian HSRF characterized by the fluorine spin-rotation constants c(1)=(1)/(2)(cxz+czx*) and c(2)=(1)/(2)(cxx-cyy), respectively. These terms in HSRF lift the parity degeneracy for ΓRV=E. The rovibrational Hamiltonian HRV was adopted from an earlier partner study [S. Macholl , J. Phys. Chem. A 113, 668 (2009)]. A good fit to the hyperfine data was obtained with a standard deviation of 3.1 kHz. In the fitting process, 12 rovibrational parameters were varied, while the remaining constants in HRV were left at the values of Macholl In addition, six hyperfine parameters were determined: four in HQN, and two in HSRF. It was found that |c(1)|=7.48(24) kHz and |c(2)|=2.423(22) kHz. This determination of c(1) is the first to be reported based on frequency measurements. In all the previous detections of parity doubling where the splittings were accounted for quantitatively, the levels involved had K=|k|=1 in studies of the ground vibrational state or G≡|k-l|=1 in
Bogdanov, Slavko; Patruno, Alessandro; Archibald, Anne M.; Bassa, Cees; Hessels, Jason W. T.; Janssen, Gemma H.; Stappers, Ben W.
2014-07-01
We present XMM-Newton and Chandra observations of the low-mass X-ray binary XSS J12270-4859, which experienced a dramatic decline in optical/X-ray brightness at the end of 2012, indicative of the disappearance of its accretion disk. In this new state, the system exhibits previously absent orbital-phase-dependent, large-amplitude X-ray modulations with a decline in flux at superior conjunction. The X-ray emission remains predominantly non-thermal but with an order of magnitude lower mean luminosity and significantly harder spectrum relative to the previous high flux state. This phenomenology is identical to the behavior of the radio millisecond pulsar (MSP) binary PSR J1023+0038 in the absence of an accretion disk, where the X-ray emission is produced in an intra-binary shock driven by the pulsar wind. This further demonstrates that XSS J12270-4859 no longer has an accretion disk and has transformed to a full-fledged eclipsing 'redback' system that hosts an active rotation-powered MSP. There is no evidence for diffuse X-ray emission associated with the binary that may arise due to outflows or a wind nebula. An extended source situated 1.'5 from XSS J12270-4859 is unlikely to be associated, and is probably a previously uncataloged galaxy cluster.
NASA Astrophysics Data System (ADS)
Harder, H.; Macholl, S.; Maeder, H.; Fusina, L.; Ozier, I.
2010-06-01
For the principal isotopomer 14N32S19F3 of thiazyl trifluoride in the degenerate fundamental state (v5=1), the hyperfine structure has been investigated in the Q-branch spectrum between 8 and 26.5 GHz using microwave Fourier transform waveguide spectrometers with a resolution limit of ≈ 30 kHz. In addition to l% -type doubling spectra and l-type resonance transitions with (Δ k =% Δ l=± 2), perturbation-allowed spectra were measured with Δ % (k-l) =± 3, ± 6. The range in J was from 13 to 61; for the lower states, kl=-3, -2, -1, 0, +1. For all the transitions, the hyperfine patterns observed are predicted to be doublets when only the nitrogen quadrupole Hamiltonian HQN is taken into account. Doublets were indeed measured for transitions with Γ RV=% A1rightarrow A2, where Γ RV is the rovibrational symmetry. However, when Γ RV=Erightarrow E, triplets and quartets were observed in addition to doublets. These anomalous hyperfine patterns are shown to be due to the (Δ k=± 1) and (Δ k=% ± 2) matrix elements of the fluorine spin-rotation Hamiltonian H% NF characterized by the fluorine spin-rotation constants % c(1)=(cxz+czxast ) and c(2)=(cxx-cyy), respectively. These terms in HNF lift the parity degeneracy for Γ RV=E. The rovibrational Hamiltonian HRV was adopted from an earlier partner study. A good fit to the hyperfine data was obtained with a standard deviation of 3.1 kHz. In the fitting process, 12 rovibrational parameters were varied, while the remaining constants in HRV were left at the values of Ref. (1). In addition, 6 hyperfine parameters were determined: four in HQN, and two in HNF. It was found that \\vert c(1)\\vert =7.48(24) kHz and \\vert c(2)\\vert =2.423(22) kHz. This determination of \\vert c(1)\\vert is the first to be reported based on frequency measurements. The key to the observation of the parity doubling lies in the severe mixing into the eigenvectors of basis vectors with several different values of kl as a result of the clustering1
NASA Astrophysics Data System (ADS)
Wang, Feng; Searles, Debra J.; von Nagy-Felsobuki, Ellak I.
1992-10-01
Ab initio variational rovibrational calculations have been performed for the ground electronic states of Li 2Na +, LiNa +2 and KLiNa +. Discrete potential and electric dipole moment surfaces were used to calculate rovibrational transition frequencies, absolute vibrational bands and line intensities. The variational rovibration calculations take into account a full description of the mechanical and electrical anharmonicity as well as vibration—rotation coupling effects. Absolute line intensities and square dipole matrix elements are given for some intense transitions within the P-, Q- and R-branches between the vibrational ground state and the lowest lying excited states.
RED DWARF DYNAMO RAISES PUZZLE OVER INTERIORS OF LOWEST-MASS STARS
NASA Technical Reports Server (NTRS)
2002-01-01
-years away in the constellation Aquila. Gliese 752A is a red dwarf that is one-third the mass of the Sun and slightly more than half its diameter. By contrast, VB10 is physically smaller than the planet Jupiter and only about nine percent the mass of our Sun. This very faint star is near the threshold of the lowest possible mass for a true star (.08 solar masses), below which nuclear fusion processes cannot take place according to current models. A team led by Linsky used Hubble's Goddard High Resolution Spectrograph (GHRS) to make a one-hour long exposure of VB10 on October 12, 1994. No detectable ultraviolet emission was seen until the last five minutes, when bright emission was detected in a flare. Though the star's normal surface temperature is 4,500 degrees Fahrenheit, Hubble's GHRS detected a sudden burst of 270,000 degrees Fahrenheit in the star's outer atmosphere. Linsky attributes this rapid heating to the presence of an intense, but unstable, magnetic field. THE INTERIOR WORKINGS OF A STELLAR DYNAMO Before the Hubble observation, astronomers thought magnetic fields in stars required the same dynamo process which creates magnetic fields on the Sun. In the classic solar model, heat generated by nuclear fusion reactions at the star's center escapes through a radiative zone just outside the core. The heat travels from the radiative core to the star's surface through a convection zone. In this region, heat bubbles to the surface by motions similar to boiling in a pot of water. Dynamos, which accelerate electrons to create magnetic forces, operate when the interior of a star rotates faster than the surface. Recent studies of the Sun indicate its convective zone rotates at nearly the same rate at all depths. This means the solar dynamo must operate in the more rapidly rotating radiative core just below the convective zone. The puzzle is that stars below 20 percent the mass of our Sun do not have radiative cores, but instead transport heat from their core through
RED DWARF DYNAMO RAISES PUZZLE OVER INTERIORS OF LOWEST-MASS STARS
NASA Technical Reports Server (NTRS)
2002-01-01
-years away in the constellation Aquila. Gliese 752A is a red dwarf that is one-third the mass of the Sun and slightly more than half its diameter. By contrast, VB10 is physically smaller than the planet Jupiter and only about nine percent the mass of our Sun. This very faint star is near the threshold of the lowest possible mass for a true star (.08 solar masses), below which nuclear fusion processes cannot take place according to current models. A team led by Linsky used Hubble's Goddard High Resolution Spectrograph (GHRS) to make a one-hour long exposure of VB10 on October 12, 1994. No detectable ultraviolet emission was seen until the last five minutes, when bright emission was detected in a flare. Though the star's normal surface temperature is 4,500 degrees Fahrenheit, Hubble's GHRS detected a sudden burst of 270,000 degrees Fahrenheit in the star's outer atmosphere. Linsky attributes this rapid heating to the presence of an intense, but unstable, magnetic field. THE INTERIOR WORKINGS OF A STELLAR DYNAMO Before the Hubble observation, astronomers thought magnetic fields in stars required the same dynamo process which creates magnetic fields on the Sun. In the classic solar model, heat generated by nuclear fusion reactions at the star's center escapes through a radiative zone just outside the core. The heat travels from the radiative core to the star's surface through a convection zone. In this region, heat bubbles to the surface by motions similar to boiling in a pot of water. Dynamos, which accelerate electrons to create magnetic forces, operate when the interior of a star rotates faster than the surface. Recent studies of the Sun indicate its convective zone rotates at nearly the same rate at all depths. This means the solar dynamo must operate in the more rapidly rotating radiative core just below the convective zone. The puzzle is that stars below 20 percent the mass of our Sun do not have radiative cores, but instead transport heat from their core through
48 CFR 15.101-2 - Lowest price technically acceptable source selection process.
Code of Federal Regulations, 2010 CFR
2010-10-01
... acceptable source selection process. 15.101-2 Section 15.101-2 Federal Acquisition Regulations System FEDERAL... Processes and Techniques 15.101-2 Lowest price technically acceptable source selection process. (a) The lowest price technically acceptable source selection process is appropriate when best value is...
48 CFR 15.101-2 - Lowest price technically acceptable source selection process.
Code of Federal Regulations, 2011 CFR
2011-10-01
... acceptable source selection process. 15.101-2 Section 15.101-2 Federal Acquisition Regulations System FEDERAL... Processes and Techniques 15.101-2 Lowest price technically acceptable source selection process. (a) The lowest price technically acceptable source selection process is appropriate when best value is...
Wang, Xianlong E-mail: pbeckman@brynmawr.edu; Mallory, Frank B.; Mallory, Clelia W.; Odhner, Hosanna R.; Beckmann, Peter A. E-mail: pbeckman@brynmawr.edu
2014-05-21
We report ab initio density functional theory electronic structure calculations of rotational barriers for t-butyl groups and their constituent methyl groups both in the isolated molecules and in central molecules in clusters built from the X-ray structure in four t-butyl aromatic compounds. The X-ray structures have been reported previously. We also report and interpret the temperature dependence of the solid state {sup 1}H nuclear magnetic resonance spin-lattice relaxation rate at 8.50, 22.5, and 53.0 MHz in one of the four compounds. Such experiments for the other three have been reported previously. We compare the computed barriers for methyl group and t-butyl group rotation in a central target molecule in the cluster with the activation energies determined from fitting the {sup 1}H NMR spin-lattice relaxation data. We formulate a dynamical model for the superposition of t-butyl group rotation and the rotation of the t-butyl group's constituent methyl groups. The four compounds are 2,7-di-t-butylpyrene, 1,4-di-t-butylbenzene, 2,6-di-t-butylnaphthalene, and 3-t-butylchrysene. We comment on the unusual ground state orientation of the t-butyl groups in the crystal of the pyrene and we comment on the unusually high rotational barrier of these t-butyl groups.
NASA Astrophysics Data System (ADS)
Wang, Xianlong; Mallory, Frank B.; Mallory, Clelia W.; Odhner, Hosanna R.; Beckmann, Peter A.
2014-05-01
We report ab initio density functional theory electronic structure calculations of rotational barriers for t-butyl groups and their constituent methyl groups both in the isolated molecules and in central molecules in clusters built from the X-ray structure in four t-butyl aromatic compounds. The X-ray structures have been reported previously. We also report and interpret the temperature dependence of the solid state 1H nuclear magnetic resonance spin-lattice relaxation rate at 8.50, 22.5, and 53.0 MHz in one of the four compounds. Such experiments for the other three have been reported previously. We compare the computed barriers for methyl group and t-butyl group rotation in a central target molecule in the cluster with the activation energies determined from fitting the 1H NMR spin-lattice relaxation data. We formulate a dynamical model for the superposition of t-butyl group rotation and the rotation of the t-butyl group's constituent methyl groups. The four compounds are 2,7-di-t-butylpyrene, 1,4-di-t-butylbenzene, 2,6-di-t-butylnaphthalene, and 3-t-butylchrysene. We comment on the unusual ground state orientation of the t-butyl groups in the crystal of the pyrene and we comment on the unusually high rotational barrier of these t-butyl groups.
Bigdeli, M.; Bordbar, G. H.; Poostforush, A.
2010-09-15
The lowest order constrained variational technique has been used to investigate some of the thermodynamic properties of spin-polarized hot asymmetric nuclear matter, such as the free energy, symmetry energy, susceptibility, and equation of state. We have shown that the symmetry energy of the nuclear matter is substantially sensitive to the value of spin polarization. Our calculations show that the equation of state of the polarized hot asymmetric nuclear matter is stiffer for higher values of the polarization as well as the isospin asymmetry parameter. Our results for the free energy and susceptibility show that spontaneous ferromagnetic phase transition cannot occur for hot asymmetric matter.
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 B{sub 0} = 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 B{sub 0} value, RR-RCS measurements in a room temperature gas cell give the rotational constants B{sub v} of the five lowest-lying thermally populated vibrationally excited states ν{sub 7/8}, ν{sub 9}, ν{sub 11/12}, ν{sub 13}, and ν{sub 14/15}. Their B{sub v} constants differ from B{sub 0} by between −1.02 MHz and +2.23 MHz. Combining the B{sub 0} 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 r{sub e}(C-C) = 1.3866(3) Å and r{sub e}(C-F) = 1.3244(4) Å. These agree with the CCSD(T)/wCVQZ r{sub e} bond lengths calculated by Demaison et al. within ±0.0005 Å. We also calculate the semi-experimental thermally averaged bond lengths r{sub g}(C-C)=1.3907(3) Å and r{sub g}(C-F)=1.3250(4) Å. These are at least ten times more accurate than two sets of experimental gas-phase electron diffraction r{sub g} bond lengths measured in the 1960s.
NASA Astrophysics Data System (ADS)
Hama, Tetsuya; Yokoyama, Masaaki; Yabushita, Akihiro; Kawasaki, Masahiro; Watanabe, Naoki
2011-05-01
Water ice is the major solid component in a variety of astrophysical environments, e.g., cold and dense molecular clouds. Photodesorption plays a dominant role in consuming ice in such cold regions. In this study, photodesorption of vibrationally ground-state H 2O( v = 0) from amorphous solid water has been investigated at 157 nm. Using a resonance-enhanced multiphoton ionization technique, the translational and rotational energy distributions of photodesorbed H 2O( v = 0) were measured, i.e., Boltzmann distributions at 1800 and 300 K, respectively. These energies are in good accordance with those predicted by classical molecular calculations for water photodesorption due to a kick-out mechanism following absorption of a single photon; hot H atom released by photodissociation of H 2O in ice transfers enough momentum to another H 2O molecule to kick it off the surface. Desorption of D 2O( v = 0) following 193 nm photoirradiation of a D 2O/H 2S mixed ice was investigated to provide further direct evidence for the operation of a kick-out mechanism. The other desorption mechanisms were also discussed in the context of possible photodesorption of vibrationally excited H 2O.
Heart-shaped nuclei: Condensation of rotational-aligned octupole phonons
Frauendorf, S.
2008-02-15
The strong octupole correlations in the mass region A{approx_equal}226 are interpreted as rotation-induced condensation of octupole phonons having their angular momentum aligned with the rotational axis. Discrete phonon energy and parity conservation generate oscillations of the energy difference between the lowest rotational bands with positive and negative parity. Anharmonicities tend to synchronize the rotation of the condensate and the quadrupole shape of the nucleus forming a rotating heart shape.
Interpretation of rapidly rotating pulsars
Weber, F. . Inst. fuer Theoretische Physik); Glendenning, N.K. )
1992-08-05
The minimum possible rotational period of pulsars, which are interpreted as rotating neutron stars, is determined by applying a representative collection of realistic nuclear equations of state. It is found that none of the selected equations of state allows for neutron star rotation at periods below 0.8--0.9 ms. Thus, this work strongly supports the suggestion that if pulsars with shorter rotational periods were found, these are likely to be strange-quark-matter stars. The conclusion that the confined hadronic phase of nucleons and nuclei is only metastable would then be almost inescapable, and the plausible ground-state in that event is the deconfined phase of (3-flavor) strange-quark-matter.
NASA Astrophysics Data System (ADS)
Lehner, M.; Jungen, M.
2015-02-01
A three-dimensional wave packet method, based on Lanczos tridiagonalization of the Hamiltonian, is introduced and applied to the three-particle predissociation of rotating D3 and H3 3{{ }2}{{A}\\prime } (2sa1\\prime ). The time-dependent propagation calculations on the (diabatic) ground state potential energy surfaces include the non-adiabatic transition from the excited initial state. Results for the eight lowest vibrational levels are presented as Dalitz plots and compared to momentum correlation measurements.
Felker, Peter M.
2014-11-14
The quantal translation-rotation (TR) states of the (p-H{sub 2}){sub 2}@5{sup 12}6{sup 4} clathrate hydrate inclusion compound have been computed. The ten-dimensional problem (in the rigid-cage and rigid-H{sub 2} approximation) is solved by first approximating the H{sub 2} moieties as spherically symmetric and solving for their 6D translational eigenstates. These are then combined with H{sub 2} free rotational states in a product basis that is used to diagonalize the full TR hamiltonian. The computed low-energy eigenstates have translational components that are essentially identical to the 6D translational eigenstates and rotational components that are 99.9% composed of rotationally unexcited H{sub 2} moieties. In other words, TR coupling is minimal for the low-energy states of the species. The low-energy level structure is found to be substantially more congested than that of the more tightly packed (p-H{sub 2}){sub 4}@5{sup 12}6{sup 4} clathrate species. The level structure is also shown to be understandable in terms of a model of (H{sub 2}){sub 2} as a semirigid diatomic species consisting of two spherically symmetric H{sub 2} pseudo-atoms.
NASA Technical Reports Server (NTRS)
1988-01-01
The NASA Bioreactor provides a low turbulence culture environment which promotes the formation of large, three-dimensional cell clusters. Due to their high level of cellular organization and specialization, samples constructed in the bioreactor more closely resemble the original tumor or tissue found in the body. NASA-sponsored bioreactor research has been instrumental in helping scientists to better understand normal and cancerous tissue development. In cooperation with the medical community, the bioreactor design is being used to prepare better models of human colon, prostate, breast and ovarian tumors. Cartilage, bone marrow, heart muscle, skeletal muscle, pancreatic islet cells, liver and kidney are just a few of the normal tissues currently being cultured in rotating bioreactors by investigators.
Lafferty, Walter; Flaud, Jean-marie; Ngom, El Hadji A.; Sams, Robert L.
2009-01-02
High resolution Fourier transform spectra of a sample of sulfur dioxide, enriched in 34S (95.3%). were completely analyzed leading to a large set of assigned lines. The experimental levels derived from this set of transitions were fit to within their experimental uncertainties using Watson-type Hamiltonians. Precise band centers, rotational and centrifugal distortion constants were determined. The following band centers in cm-1 were obtained: ν0(3ν2)=1538.720198(11), ν0(ν1+ν3)=2475.828004(29), ν0(ν1+ν2+ν3)=2982.118600(20), ν0(2ν3)=2679.800919(35), and ν0(2ν1+ν3)=3598.773915(38). The rotational constants obtained in this work have been fit together with the rotational constants of lower lying vibrational states [ W.J. Lafferty, J.-M. Flaud, R.L. Sams and EL Hadjiabib, in press] to obtain equilibrium constants as well as vibration-rotation constants. These equilibrium constants have been fit together with those of 32S16O2 [J.-M. Flaud and W.J. Lafferty, J. Mol. Spectrosc. 16 (1993) 396-402] leading to an improved equilibrium structure. Finally the observed band centers have been fit to obtain anharmonic rotational constants.
Rotational Rehybridization and the High Temperature Phase of UC2
Wen, Xiaodong; Rudin, Sven P.; Batista, Enrique R.; Clark, David L.; Scuseria, Gustavo E.; Martin, Richard L.
2012-12-03
The screened hybrid approximation (HSE) of density functional theory (DFT) is used to examine the structural, optical, and electronic properties of the high temperature phase, cubic UC(2). This phase contains C(2) units with a computed C-C distance of 1.443 Å which is in the range of a CC double bond; U is formally 4+, C(2) 4-. The closed shell paramagnetic state (NM) was found to lie lowest. Cubic UC(2) is found to be a semiconductor with a narrow gap, 0.4 eV. Interestingly, the C(2) units connecting two uranium sites can rotate freely up to an angle of 30°, indicating a hindered rotational solid. Ab-initio molecular dynamic simulations (HSE) show that the rotation of C(2) units in the low temperature phase (tetragonal UC(2)) occurs above 2000 K, in good agreement with experiment. The computed energy barrier for the phase transition from tetragonal UC(2) to cubic UC(2) is around 1.30 eV per UC(2). What is fascinating about this system is that at high temperature, the phase transformation to the cubic phase is associated with a rehybridization of the C atoms from sp to sp(3).
Lowest weight representations of super Schroedinger algebras in one dimensional space
Aizawa, N.
2011-01-15
Lowest weight modules, in particular, Verma modules over the N=1,2 super Schroedinger algebras in (1 + 1) dimensional spacetime are investigated. The reducibility of the Verma modules is analyzed via explicitly constructed singular vectors. The classification of the irreducible lowest weight modules is given for both massive and massless representations. A vector field realization of the N=1,2 super Schroedinger algebras is also presented.
The automated rotating shadowband spectroradiometer
Harrison, L.; Beik, M.A.; Michalsky, J.J.
1993-11-01
We are developing a photodiode array rotating shadowband spectroradiometer (RSS) as part of the Instrument Development Program (IDP) of the Atmospheric Radiation Measurement (ARM) Program of the United States Department of Energy (DOE). This instrument uses the automated rotating shadowband technique to separate and measure the spectrally resolved direct-normal, total horizontal, and diffuse horizontal irradiances in the 360 to 1060 nm wavelength region. It is intended as an instrument for the central facility of each of the cloud and radiation testbed (CART) sites, and will complement the array of multi-filter rotating shadowband radiometers (MFRSR) currently being deployed by ARM and other research programs including TOGA/COARE.
Rotationally resolved B̃←X̃ electronic spectra of the isopropoxy radical: A comparative study.
Liu, Jinjun; Melnik, Dmitry; Miller, Terry A
2013-09-01
The B̃-X̃ laser-induced-fluorescence spectrum of jet-cooled isopropoxy radical (i-C3H7O[middle dot]) has been recorded. Using an isolated state model the observed rotational and fine structure of the origin band has been well simulated to determine rotational constants for both the X̃ and B̃ states and the electron spin-rotation constants of the X̃ state. The line intensities are well simulated with a parallel transition type, requiring the same symmetry for the levels involved of each the X̃ and B̃ state, which confirms the previous suggestion that going from ethoxy (C2H5O[middle dot]) to isopropoxy, the energy ordering of the electron configurations with in- and out-of-plane half-filled p-orbitals of the oxygen atom is reversed and the ground vibronic symmetry changes from a" to a'. However, the observed spin-rotation coupling constants are not consistent with their predication from either semi-empirical theory or quantum chemical calculations. Additionally, the lack of observed transitions involving the out-of-plane transition moment component is not consistent with high level electronic structure calculations suggesting mixing of vibronic levels by strong spin-orbit coupling. A new twofold model has been developed that explicitly includes Coriolis and spin-orbit coupling between different vibronic levels. This model renders the discrepancy between theoretical and experimental spin-rotation constants moot. Moreover, it determines independently the contributions to the observed splitting between the lowest two levels, resulting from non-relativistic kinetic and Coulombic effects, and that due to the relativistic spin-orbit interaction. The experimental values show that these effects are comparable, but that the vibronic one is slightly more important. This result is at variance with state-of-the-art electronic structure calculations which otherwise do a remarkably good job of describing the ground state of isopropoxy. PMID:24028118
NASA Astrophysics Data System (ADS)
Eriksen, Janus J.; Sauer, Stephan P. A.; Mikkelsen, Kurt V.; Christiansen, Ove; Jensen, Hans Jørgen Aa.; Kongsted, Jacob
2013-07-01
We investigate the failure of time-dependent density functional theory (TDDFT) with the CAM-B3LYP exchange-correlation (xc) functional coupled to the polarisable embedding (PE) scheme (PE-CAM-B3LYP) in reproducing the solvatochromic shift of the lowest intense charge-transfer excitation in para-nitroaniline (pNA) in water by comparing with results obtained with the coupled cluster singles and doubles (CCSD) model also coupled to the polarisable embedding scheme (PE-CCSD). We determine the amount of charge separation in the ground and excited charge-transfer state with both methods by calculating the electric dipole moments in the gas phase and for 100 solvent configurations. We find that CAM-B3LYP overestimates the amount of charge separation inherent in the ground state and TDDFT/CAM-B3LYP drastically underestimates this amount in the excited charge-transfer state. As the errors in the solvatochromatic shift are found to be inverse proportional to the change in dipole moment upon excitation, we conclude that the flaws in the description of the solvatochromic shift of this excitation are related to TDDFT itself and how it responds to the solvent effects modelled by the PE scheme. We recommend therefore to benchmark results of TDDFT calculations with CAM-B3LYP for intramolecular charge-transfer excitations in molecular systems similar to pNA against higher level ab initio wave function methods, like, e.g. CCSD, prior to their use. Using the calculated change in dipole moment upon excitation as a measure for charge-transfer character, we furthermore confirm that the difference between excitation energies calculated with TDDFT and with the Tamm-Dancoff approximation (TDA) to TDDFT is indeed correlated with the charge-transfer character of a given electronic transition both in vacuo and in solution. This is supported by a corresponding correlation between the change in dipole moment and the size of the Λ index diagnostic for the investigated CT excitation.
Park, G Barratt; Krüger, Bastian C; Meyer, Sven; Wodtke, Alec M; Schäfer, Tim
2016-08-10
The formaldehyde molecule is an important model system for understanding dynamical processes in small polyatomic molecules. However, prior to this work, there have been no reports of a resonance-enhanced multiphoton ionization (REMPI) detection scheme for formaldehyde suitable for rovibrationally state-selective detection in molecular beam scattering experiments. Previously reported tunable REMPI schemes are either non-rotationally resolved, involve multiple resonant steps, or involve many-photon ionization steps. In the current work, we present a new 1 + 1' REMPI scheme for formaldehyde. The first photon is tunable and provides rotational resolution via the vibronically allowed Ã (1)A2 ← X[combining tilde] (1)A1 transition. Molecules are then directly ionized from the Ã state by one photon of 157 nm. The results indicate that the ionization cross section from the 4(1) vibrational level of the Ã state is independent of the rotational level used as intermediate, to within experimental uncertainty. The 1 + 1' REMPI intensities are therefore directly proportional to the Ã ← X[combining tilde] absorption intensities and can be used for quantitative measurement of X[combining tilde]-state population distributions. PMID:27461406
NASA Technical Reports Server (NTRS)
1984-01-01
The bulk of the muon spin rotation research work centered around the development of the muon spin rotation facility at the Alternating Gradient Synchrotron (AGS) of Brookhaven National Laboratory (BNL). The collimation system was both designed and fabricated at Virginia State University. This improved collimation system, plus improvements in detectors and electronics enabled the acquisition of spectra free of background out to 15 microseconds. There were two runs at Brookhaven in 1984, one run was devoted primarily to beam development and the other run allowed several successful experiments to be performed. The effect of uniaxial strain on an Fe(Si) crystal at elevated temperature (360K) was measured and the results are incorporated herein. A complete analysis of Fe pulling data taken earlier is included.
A Translational Polarization Rotator
NASA Technical Reports Server (NTRS)
Chuss, David T.; Wollack, Edward J.; Pisano, Giampaolo; Ackiss, Sheridan; U-Yen, Kongpop; Ng, Ming wah
2012-01-01
We explore a free-space polarization modulator in which a variable phase introduction between right- and left-handed circular polarization components is used to rotate the linear polarization of the outgoing beam relative to that of the incoming beam. In this device, the polarization states are separated by a circular polarizer that consists of a quarter-wave plate in combination with a wire grid. A movable mirror is positioned behind and parallel to the circular polarizer. As the polarizer-mirror distance is separated, an incident liear polarization will be rotated through an angle that is proportional to the introduced phase delay. We demonstrate a prototype device that modulates Stokes Q and U over a 20% bandwidth.
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NASA Astrophysics Data System (ADS)
Jacovella, Ugo; Gans, Bérenger; Merkt, Frédéric
2015-08-01
Pulsed-field-ionisation zero-kinetic-energy (PFI-ZEKE) photoelectron spectra of 2-butyne (CH3-CC-CH3) and its fully deuterated isotopomer have been recorded in the region of the origin band of the ? ionising transition. The spectral congestion originating from the combined effects of the internal rotation of the methyl groups, the spin-orbit coupling, and the Jahn-Teller effect prevented the full resolution of the rotational structure of the photoelectron spectra. A tentative analysis of the rotational branch structure of the photoelectron spectra using rovibronic photoionisation selection rules derived in the permutation-inversion spin double group G36(M2) suggests a splitting of ∼10.5 cm-1 between the two spin-orbit components E3/2 and E1/2 of the ? 2 E1 ground state and an almost free internal rotation of the methyl groups in the cations. Assignments are proposed for several low-lying vibrational levels of the cations.
High-resolution photodetachment spectroscopy from the lowest threshold of O{sup -}
Joiner, Anne; Mohr, Robert H.; Yukich, J. N.
2011-03-15
We conducted photodetachment spectroscopy near the lowest detachment threshold from O{sup -} in a 1-T field with sufficient resolution to observe a magnetic field structure similar to that observed in experiments conducted at the threshold of the electron affinity. These observations included not only cyclotron structure but also, to a smaller degree, individual Zeeman thresholds. The experiment was conducted in a Penning ion trap and with a single-mode, tunable, amplified diode laser. Finally, analysis of our results yielded a measurement of the lowest threshold energy.
NASA Astrophysics Data System (ADS)
Canè, E.; Di Lonardo, G.; Fusina, L.; Jerzembeck, W.; Bürger, H.; Breidung, J.; Thiel, W.
2006-01-01
The high resolution infrared spectrum of 121SbD 3, recorded between 20 and 350 cm -1 and in the regions of bending and stretching fundamental bands, centred at 600 and 1350 cm -1, has been analysed. Splittings of the K″=3, 6 lines have been observed both in the rotation and ro-vibration spectra. A large number of 'perturbation allowed' transitions with selection rules Δ(k-ℓ)=±3, ±6 and ±9 have been identified in all fundamental bands. Accurate ground state molecular parameters have been determined fitting simultaneously the rotational transitions and about 9000 ground state combination differences obtained from lines assigned in the ro-vibrational spectra. The A and B reductions of the rotational Hamiltonian have been applied in the analysis of the ground state. They provided almost equivalent results. The molecular parameters of the 1 1, 2 1, 3 1 and 4 1 states have been obtained from the simultaneous analysis of the ν1 ( A1)/ ν3 ( E) stretching and of the ν2 ( A1)/ ν4 ( E) bending dyads. In fact, the corresponding excited states are affected by strong perturbations due to Coriolis and k-type rovibrational interactions that have been treated explicitly in the model adopted for the analysis. Improved effective ground state and equilibrium geometries have been determined and compared to those of 121SbH 3 and of 123SbD 3. Ab initio calculations at the coupled cluster CCSD(T) level with an energy-consistent large-core pseudopotential and large basis sets have been carried out to determine the equilibrium structure, the anharmonic force field, and the associated spectroscopic constants of 121-stibine. The theoretical constants and structural parameters are in good agreement with the experimental data.
Broadband Rotational Spectroscopy
NASA Astrophysics Data System (ADS)
Pate, Brooks
2014-06-01
The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De
Sharkey, Keeper L.; Kirnosov, Nikita; Adamowicz, Ludwik
2015-05-07
Direct variational calculations where the Born-Oppenheimer approximation is not assumed are done for all rovibrational states of the D{sub 2} molecule corresponding to first excited rotational level (the N = 1 states). All-particle explicitly correlated Gaussian basis functions are used in the calculations. The exponential parameters of the Gaussians are optimized with the aid of analytically calculated energy gradient determined with respect to these parameters. The results allow to determine the ortho-para spin isomerization energies as a function of the vibrational quantum number.
NASA Astrophysics Data System (ADS)
Gurusinghe, Ranil M.; Tubergen, Michael
2015-06-01
A mini-cavity microwave spectrometer was used to record the rotational spectra arising from 2-phenylethyl methyl ether and its weakly bonded argon complex in the frequency range of 10.5 - 22 GHz. Rotational spectra were found for two stable conformations of the monomer: anti-anti and gauche-anti, which are 1.4 kJ mol-1 apart in energy at wB97XD/6-311++G(d,p) level. Doubled rotational transitions, arising from internal motion of the methyl group, were observed for both conformers. The program XIAM was used to fit the rotational constants, centrifugal distortion constants, and barrier to internal rotation to the measured transition frequencies of the A and E internal rotation states. The best global fit values of the rotational constants for the anti-anti conformer are A= 3799.066(3) MHz, B= 577.95180(17) MHz, C= 544.7325(3) MHz and the A state rotational constants of the gauche-anti conformer are A= 2676.1202(7) MHz, B= 760.77250(2) MHz, C= 684.78901(2) MHz. The rotational spectrum of 2-phenylethyl methyl ether - argon complex is consistent with the geometry where argon atom lies above the plane of the benzene moiety of gauche-anti conformer. Tunneling splittings were too small to resolve within experimental accuracy, likely due to an increase in three fold potential barrier when the argon complex is formed. Fitted rotational constants are A= 1061.23373(16) MHz, B= 699.81754(7) MHz, C= 518.33553(7) MHz. The lowest energy solvated ether - water complex with strong intermolecular hydrogen bonding has been identified theoretically. Progress on the assignment of the water complex will also be presented.
Schleicher, David G.; Knight, Matthew M.; Levine, Stephen E.
2013-11-01
We present new lightcurve measurements of Comet 10P/Tempel 2 carried out with Lowell Observatory's Discovery Channel Telescope in early 2013 when the comet was at aphelion. These data represent some of the first science obtained with this new 4.3 m facility. With Tempel 2 having been observed to exhibit a small but ongoing spin-down in its rotation period for over two decades, our primary goals at this time were two-fold. First, to determine its current rotation period and compare it to that measured shortly after its most recent perihelion passage in 2010, and second, to disentangle the spin-down from synodic effects due to the solar day and Earth's orbital motion and to determine the sense of rotation, i.e., prograde or retrograde. At our midpoint of 2013 February 24, the observed synodic period is 8.948 ± 0.001 hr, exactly matching the predicted prograde rotation solution based on 2010 results, and yields a sidereal period of the identical value due to the solar and Earth synodic components just canceling out during the interval of the 2013 observations. The retrograde solution is ruled out because the associated sidereal periods in 2010 and 2013 are quite different even though we know that extremely little outgassing, needed to produce torques, occurred in this interval. With a definitive sense of rotation, the specific amounts of spin-down to the sidereal period could be assessed. The nominal values imply that the rate of spin-down has decreased over time, consistent with the secular drop in water production since 1988. Our data also exhibited an unexpectedly small lightcurve amplitude which appears to be associated with viewing from a large, negative sub-Earth latitude, and a lightcurve shape deviating from a simple sinusoid implying a highly irregularly shaped nucleus.
Lowest Q2 Measurement of the gamma*p-> Delta Reaction: Probing the Pionic Contribution
Stave, Sean
2006-06-30
The first excited state of the proton, the Delat, can be reached through a magnetic dipole spin flip of one of the quarks (M1) or through electric and Coulomb quadrupole terms (E2 and C2) which indicate a deviation from spherical symmetry. The quark models using the color hyperfine interaction underestimate the size of the quadrupole terms by more than an order of magnitude. Models using the pion cloud do a much better job of describing the data. This is expected due to the spontaneous breaking of chiral symmetry which leads to a cloud of virtual p wave pions which introduce the non-spherical amplitudes. The data presented in this work fill gaps in the low Q², long distance region where the pion cloud is expected to dominate and to produce significant Q2 variation. The p(e¯, ép)π° reaction was measured in the Δ region at Q² = 0.060 (GeV/c)², the lowest Q² to date for pion electroproduction, utilizing out-of-plane magnetic spectrometers at the Mainz Microtron in Germany. This work reports results for the dominant transition magnetic dipole amplitude and the quadrupole to dipole ratios obtained from fitting the new data with models using a three parameter, resonant multipole fit: M³/²1+ = (40.33 +- 0.63stat+syst +-model)(10-³/mπ+), E2/M1=Re(E³/²1+M³/²1+) = (-2.28+- 0.29stat+syst +- 0.20model)%, and C2/M1 =Re(S³/²1+/M³/²1+) poles disagree with predictions of the quark models but are in reasonable agreement with a chiral extrapolation of lattice QCD, chiral effective field theory and dynamical model results confirming the dominance and general Q² variation of the long range pionic contribution. While there is qualitative agreement with the models, there is no quantitative agreement thus indicating the need for further improvement of the models.
41 CFR 101-26.100-1 - Procurement of lowest cost items.
Code of Federal Regulations, 2010 CFR
2010-07-01
... cost items. 101-26.100-1 Section 101-26.100-1 Public Contracts and Property Management Federal Property... SOURCES AND PROGRAM 26.1-General § 101-26.100-1 Procurement of lowest cost items. GSA provides lines of... differ in terms of price, quality, and essential characteristics, they often can serve the...
41 CFR 101-26.100-1 - Procurement of lowest cost items.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 41 Public Contracts and Property Management 2 2011-07-01 2007-07-01 true Procurement of lowest cost items. 101-26.100-1 Section 101-26.100-1 Public Contracts and Property Management Federal Property Management Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS SUPPLY AND PROCUREMENT 26-PROCUREMENT SOURCES AND PROGRAM 26.1-General §...
Influencing Young Adolescents' Motivation in the Lowest Level of Secondary Education
ERIC Educational Resources Information Center
Peetsma, Thea; Van der Veen, Ineke
2015-01-01
After the transition to secondary school around age 12, a well-known decline in young adolescents' motivation for learning causes particular concerns in the lowest level of secondary education, where the percentage of early school leavers is highest. This article focuses on a study of the effects of an intervention, designed to enhance…
Location of the lowest exciton in C 60 single crystal by two-photon excitation spectroscopy
NASA Astrophysics Data System (ADS)
Muccini, M.; Danieli, R.; Zamboni, R.; Taliani, C.; Mohn, H.; Müller, W.; ter Meer, H. U.
1995-10-01
Two-photon excitation of C 60 single crystal at 4 K shows a sharp band at 1.846 eV which is assigned to the lowest forbidden Frenkel singlet exciton of T 1g symmetry. This assignment is supported by the analysis of Herzberg-Teller induced photoluminescence.
ERIC Educational Resources Information Center
Le Patner, Michelle B.
2012-01-01
This study examined the American Recovery and Reinvestment Act federal mandate of the Transformation Intervention Model (TIM) outlined by the School Improvement Grant, which was designed to turn around persistently lowest achieving schools. The study was conducted in four high schools in a large Southern California urban district that selected the…
The Lowest Quartile African Americans Taking Advanced Placement Language and Literature
ERIC Educational Resources Information Center
Hale, David P.
2007-01-01
As the lead Advanced Placement (AP) English teacher at Suncoast High School, a magnet school, the author started a pilot program teaching the lowest quartile group of African American students the AP English Literature and Composition course their senior year. Their educational background was limited, and several were not able to write a complete…
Graduation Rates Hit Lowest Level in 7 Years for Athletes in Football and Basketball.
ERIC Educational Resources Information Center
Suggs, Welch
1999-01-01
Graduation rates of football players and men's and women's basketball players at National Collegiate Athletic Association Division I colleges have reached their lowest level in seven years, with fewer black athletes graduating than at any time since the mid-1980s. Eight universities graduated at least 90% of athletes enrolling between 1989 and…
Digital rotation measurement unit
Sanderson, S.N.
1983-09-30
A digital rotation indicator is disclosed for monitoring the position of a valve member having a movable actuator. The indicator utilizes mercury switches adapted to move in cooperation with the actuator. Each of the switches produces an output as it changes state when the actuator moves. A direction detection circuit is connected to the switches to produce a first digital signal indicative of the direction of rotation of the actuator. A count pulse generating circuit is also connected to the switches to produce a second digital pulse signal having count pulses corresponding to a change of state of any of the mercury switches. A reset pulse generating circuit is provided to generate a reset pulse each time a count pulse is generated. An up/down counter is connected to receive the first digital pulse signal and the second digital pulse signal and to count the pulses of the second digital pulse signal either up or down depending upon the instantaneous digital value of the first digital signal whereby a running count indicative of the movement of the actuator is maintained.
NASA Astrophysics Data System (ADS)
Yadav, Amarjeet; Mishra, P. C.
2014-04-01
Polycyclic aromatic hydrocarbons (PAHs) form an important class of molecules as they are ubiquitous, pollute air and cause severe health problems. Lowest vertical π-π* singlet-singlet or triplet-triplet excitation energies and corresponding oscillator strengths were studied for several linear and two-dimensional PAHs employing time-dependent density functional theory. Excited-state electron density, molecular electrostatic potential (MEP) and spin density distributions in the PAHs, along with ground-state chemical hardness, were also studied. It has been found that, generally, excitation energies and oscillator strengths decrease with increase in PAH size, and excitation energies and chemical hardness are strongly linearly correlated. Enhanced electron density edge effect, which was found to occur in the ground states of the molecules, continues to hold in their excited states also. A strong similarity between the ground and π-π* excited-state MEP maps suggests that σ electrons are the main contributors to the enhanced electron density at the edges. Due to their strong electronic absorption transitions in the visible and infrared regions, the PAHs can be used for harnessing solar energy efficiently.
NASA Astrophysics Data System (ADS)
Vanderlinden, Karl; Pachepsky, Yakov; Pederera, Aura; Martinez, Gonzalo; Espejo, Antonio Jesus; Giraldez, Juan Vicente
2014-05-01
Unique water transfer and retention properties of Vertisols strongly affect their use in rainfed agriculture in water-limited environments. Despite the agricultural importance of the hydraulic properties of those soils, water retention data dryer than the wilting point are generally scarce, mainly as a result of practical constraints of traditional water retention measurement methods. In this work we provide a detailed description of regionalized water retention data from saturation to oven dryness, obtained from 54 minimally disturbed topsoil (0-0.05m) samples collected at a 3.5-ha experimental field in SW Spain where conventional tillage (CT) and direct drilling (DD) is compared in a wheat-sunflower-legume crop rotation on a Vertisol. Water retention was measured from saturation to oven dryness using sand and sand-kaolin boxes, a pressure plate apparatus and a dew point psychrometer, respectively. A common shape of the water retention curve (WRC) was observed in both tillage systems, with a strong discontinuity in its slope near -0.4 MPa and a decreasing spread from the wet to the dry end. A continuous function, consisting of the sum of a double exponential model (Dexter et al, 2008) and the Groenevelt and Grant (2004) model could be fitted successfully to the data. Two inflection points in the WRC were interpreted as boundaries between the structural and the textural pore spaces and between the textural and the intra-clay aggregate pore spaces. Water retention was significantly higher in DD (p<0.05) for pressure heads ranging from -0.006 to -0.32 MPa, and from -1.8 to -3.3 MPa. The magnitude of these differences ranged from 0.006 to 0.015 kg kg-1. The differential water capacity and associated equivalent pore-size distribution showed that these differences could be attributed to a combined effect of tillage and compaction, increasing and decreasing the amount of the largest pores in CT and DD, respectively, but resulting in a proportionally larger pore space
NASA Astrophysics Data System (ADS)
Sun, Fadi; Ye, Jinwu; Liu, Wu-Ming
2015-03-01
We show that Rotated Heisenberg (RH) model is a new class of quantum spin models to describe magnetic materials with strong spin-orbit couplings (SOC). We introduce Wilson loops to characterize frustrations and gauge equivalent class. For a special equivalent class, we identify a new spin-orbital entangled commensurate ground state. It supports a novel gapped elementary excitation named as in-commensurate magnons which have two gap minima continuously tuned by the SOC strength. At low temperatures, the in-commensurate magnons lead to dramatic effects in all physical quantities such as density of states, specific heat, magnetization and various spin correlation functions. At high temperatures, the specific heat and transverse spin structure factors depend on the SOC strength explicitly. We argue that one gauge may be realized in current experiments and other gauges may also be realized in near future experiments. Various experimental detections are discussed. This work is supported by NSF-DMR-1161497, NSFC-11174210.
NASA Technical Reports Server (NTRS)
Rudolph, H.; Mckoy, V.; Dixit, S. N.; Huo, W. M.
1988-01-01
Results are presented for the rotationally resolved photoelectron spectra resulting from a (2 + 1) one-color resonant enhanced multiphoton ionization (REMPI) of NO via the rotationally clean S21(11.5) and mixed S11(15.5) + R21(15.5) branches of the 0-0 transition in the D-X band. The calculations were done in the fixed-nuclei frozen core approximation. The resulting photoionization spectra, convoluted with a Lorentzian detection function, agree qualitatively with experimental results of Viswanathan et al. (1986) and support their conclusion that the nonspherical nature of the molecular potential creates a substantial l-mixing in the continuum, which in turn leads to the intense Delta N = 0 peak. The rather strong photoelectron energy dependence of the rotational branching ratios of the D 2Sigma(+) S21(11.5) line was investigated and compared to the weak energy dependence of the A 2Sigma(+) R22(21.5) line.
Formulas for determining rotational constants
NASA Astrophysics Data System (ADS)
Guelachvili, G.
This document is part of Subvolume B `Linear Triatomic Molecules', Part 9, of Volume 20 `Molecular Constants mostly from Infrared Spectroscopy' of Landolt-Börnstein Group II `Molecules and Radicals'. Part of the introduction, it states formulas for determining rotational constants, band center, band origin, and quadrupole coupling. Specific comments relate to BHO (HBO) and COS (OCS).
Transitions in turbulent rotating convection
NASA Astrophysics Data System (ADS)
Rajaei, Hadi; Alards, Kim; Kunnen, Rudie; Toschi, Federico; Clercx, Herman; Fluid Dynamics Lab Team
2015-11-01
This study aims to explore the flow transition from one state to the other in rotating Rayleigh-Bènard convection using Lagrangian acceleration statistics. 3D particle tracking velocimetry (3D-PTV) is employed in a water-filled cylindrical tank of equal height and diameter. The measurements are performed at the center and close to the top plate at a Rayleigh number Ra = 1.28e9 and Prandtl number Pr = 6.7 for different rotation rates. In parallel, direct numerical simulation (DNS) has been performed to provide detailed information on the boundary layers. We report the acceleration pdfs for different rotation rates and show how the transition from weakly to strongly rotating Rayleigh-Bènard affects the acceleration pdfs in the bulk and boundary layers. We observe that the shapes of the acceleration PDFs as well as the isotropy in the cell center are largely unaffected while crossing the transition point. However, acceleration pdfs at the top show a clear change at the transition point. Using acceleration pdfs and DNS data, we show that the transition between turbulent states is actually a boundary layer transition between Prandtl-Blasius type (typical of non-rotating convection) and Ekman type.
Equilibrium Strategy and Population-Size Effects in Lowest Unique Bid Auctions
NASA Astrophysics Data System (ADS)
Pigolotti, Simone; Bernhardsson, Sebastian; Juul, Jeppe; Galster, Gorm; Vivo, Pierpaolo
2012-02-01
In lowest unique bid auctions, N players bid for an item. The winner is whoever places the lowest bid, provided that it is also unique. We use a grand canonical approach to derive an analytical expression for the equilibrium distribution of strategies. We then study the properties of the solution as a function of the mean number of players, and compare them with a large data set of internet auctions. The theory agrees with the data with striking accuracy for small population-size N, while for larger N a qualitatively different distribution is observed. We interpret this result as the emergence of two different regimes, one in which adaptation is feasible and one in which it is not. Our results question the actual possibility of a large population to adapt and find the optimal strategy when participating in a collective game.
Poverty Rate Hits Lowest Level since 1979 as Unemployment Reaches a 30-Year Low. News Release.
ERIC Educational Resources Information Center
Center on Budget and Policy Priorities, Washington, DC.
This brief presents some U.S. Census figures on poverty and employment patterns for 1999. The percentage of U.S. citizens living in poverty declined to 11.8 percent in 1999, the lowest poverty rate since 1979, as poverty rates for people aged 65 and over, African Americans, Hispanic Americans, and people living in the South fell to all-time lows.…
Are the lowest-cost healthful food plans culturally and socially acceptable?
Maillot, Matthieu; Darmon, Nicole; Drewnowski, Adam
2014-01-01
Objective Nutritious yet inexpensive foods do exist. However, many such foods are rejected by the low-income consumer. Is it because their use violates unspoken social norms? The present study was designed to assess the variety and cost of the lowest-cost market basket of foods that simultaneously met required dietary standards and progressively stricter consumption constraints. Design A mathematical optimisation model was used to develop the lowest-cost food plans to meet three levels of nutritional requirements and seven levels of consumption constraints. Subjects: The nationally representative INCA (National Individual Survey of Food Consumption) dietary survey study of 1332 adults provided population estimates of food consumption patterns in France. Food plan costs were based on retail food prices. Results The lowest-cost food plans that provided 9204 kJ/d (2200 kcal/d) for men and 7531 kJ/d (1800 kcal/d) for women and met specified dietary standards could be obtained for ,1?50 h/d. The progressive imposition of consumption constraints designed to create more mainstream French diets sharply increased food plan costs, without improving nutritional value. Conclusions Minimising diet costs, while meeting nutrition standards only, led to food plans that provided little variety and deviated substantially from social norms. Aligning the food plan with mainstream consumption led to higher costs. Food plans designed for low-income groups need to be socially acceptable as well as affordable and nutritious. PMID:20105388
Rotating polygon instability of a swirling free surface flow.
Tophøj, L; Mougel, J; Bohr, T; Fabre, D
2013-05-10
We explain the rotating polygon instability on a swirling fluid surface [G. H. Vatistas, J. Fluid Mech. 217, 241 (1990) and Jansson et al., Phys. Rev. Lett. 96, 174502 (2006)] in terms of resonant interactions between gravity waves on the outer part of the surface and centrifugal waves on the inner part. Our model is based on potential flow theory, linearized around a potential vortex flow with a free surface for which we show that unstable resonant states appear. Limiting our attention to the lowest order mode of each type of wave and their interaction, we obtain an analytically soluble model, which, together with estimates of the circulation based on angular momentum balance, reproduces the main features of the experimental phase diagram. The generality of our arguments implies that the instability should not be limited to flows with a rotating bottom (implying singular behavior near the corners), and indeed we show that we can obtain the polygons transiently by violently stirring liquid nitrogen in a hot container. PMID:23705710
Rotation and Rotation-Vibration Spectroscopy of the 0+-0- Inversion Doublet in Deuterated Cyanamide
NASA Astrophysics Data System (ADS)
Kisiel, Zbigniew; Kraśnicki, Adam; Jabs, Wolfgang; Herbst, Eric; Winnewisser, Brenda P.; Winnewisser, Manfred
2013-10-01
The pure rotation spectrum of deuterated cyanamide was recorded at frequencies from 118 to 649 GHz, which was complemented by measurement of its high-resolution rotation-vibration spectrum at 8-350 cm-1. For D2NCN the analysis revealed considerable perturbations between the lowest Ka rotational energy levels in the 0+ and 0- substates of the lowest inversion doublet. The final data set for D2NCN exceeded 3000 measured transitions and was successfully fitted with a Hamiltonian accounting for the 0+ - 0- coupling. A smaller data set, consisting only of pure rotation and rotation-vibration lines observed with microwave techniques was obtained for HDNCN, and additional transitions of this type were also measured for H2NCN. The spectroscopic data for all three isotopic species were fitted with a unified, robust Hamiltonian allowing confident prediction of spectra well into the terahertz frequency region, which is of interest to contemporary radioastronomy. The isotopic dependence of the determined inversion splitting, -E = 16.4964789(8), 32.089173(3), and 49.567770(6) cm-1, for D2NCN, HDNCN, and H2NCN, respectively, is found to be in good agreement with estimates from a simple reduced quartic-quadratic double minimum potential.
Transport Coefficients in Rotating Weakly Compressible Turbulence
NASA Technical Reports Server (NTRS)
Rubinstein, Robert; Zhou, Ye; Erlebacher, Gordon
1998-01-01
Analytical studies of compressible turbulence have found that compressible velocity fluctuations create both effective fluid transport properties and an effective equation of state. This paper investigates the effects of rotation on compressible turbulence. It is shown that rotation modifies the transport properties of compressible turbulence by replacing the turbulence time scale by a rotational time scale, much as rotation modifies the transport properties of incompressible turbulence. But thermal equilibrium properties are modified in a more complex manner. Two regimes are possible: one dominated by incompressible fluctuations, in which the sound speed is modified as it is in non-rotating turbulence, and a rotation dominated regime in which the sound speed enhancement is rotation dependent. The dimensionless parameter which discriminates between regimes is identified. In general, rotation is found to suppress the effects of compressibility. A novel feature of the present analysis is the use of a non-Kolmogorov steady state as the reference state of turbulence. introduction of such steady states expands the power and utility of analytical turbulence closures to a wider range of problems.
Cohen, E.A.; Mueller, H.S.P.; Tan, T.L.
1996-12-31
The {nu}{sub 1} and {nu}{sub 2} bands of DOBr centered near 2673.2 and 853.4 cm{sup -1} respectively have been observed at 0.006 cm{sup -1} resolution. The {nu}{sub 1} band is perturbed by an anharmonic resonance ({Delta}K{sub a} = 0) with 3 {nu}{sub 3}+ {nu}{sub 2}. In addition, the millimeter spectra arising from the {upsilon}{sub 2} = 1 and {upsilon}{sub 3} = 1 states have been observed. All rotational and vibrational spectra from both bromine isotopic species have been fitted with a single calculation. The perturbation in the {nu}{sub 1} band has been well described. Equilibrium rotational and centrifugal distortion constants have been determined. The equilibrium structure has been derived from the DOBr and HOBr rotational constants. The harmonic force field has been calculated and will be compared with that of HOCl and with those derived from ab initio calculations. Changes in quadrupole coupling with the BrO stretch and DOBr bend have been determined.
Bertino, M.F.; Miret-Artes, S.; Toennies, J.P.; Benedek, G.
1997-10-01
Rotationally mediated focused inelastic resonances (RMFIR{close_quote}s) in the angular distributions of D{sub 2} scattered from Cu(001) are observed. The FIR effect involves a phonon-assisted focusing of an incident beam of arbitrary energy and direction into a final channel of one single well-defined energy and direction. Surprisingly for an incident energy E{sub i}=27meV the RMFIR conditions for the scattered beam coincide with the kinematic conditions required for a further elastic selective adsorption mechanism called the rotationally mediated critical kinematic (RMCK) effect. By taking advantage of the RMFIR and elastic RMCK effects, three effective bound states of energy {epsilon}{sub n,J}={minus}21.5meV, {minus}12.4meV, and {minus}10.3meV are determined. They are attributed to the lowest bound states {epsilon}{sub 0}={minus}28.9meV and {epsilon}{sub 1}={minus}19.8meV combined with the rotational excitation energy for J=1 to be B{sub rot}J(J+1)=7.41meV, respectively, and {epsilon}{sub 3}={minus}10.3meV combined with the rotational ground state (J=0). While the {epsilon}{sub 1} and {epsilon}{sub 3} states appear as maxima in the angular distribution at RMFIR conditions, the {epsilon}{sub 0} yields a striking minimum which represents the first evidence of what we call an anti-FIR feature. Theoretical arguments to explain the different FIR signatures observed are provided. A fit of a phenomenological interaction potential to the experimental bound-state values yields a value for the well depth D=32.5meV which is somewhat deeper than that found previously. {copyright} {ital 1997} {ital The American Physical Society}
Rotational preference in gymnastics.
Heinen, Thomas; Jeraj, Damian; Vinken, Pia M; Velentzas, Konstantinos
2012-06-01
In gymnastics, most skills incorporate rotations about one or more body axes. At present, the question remains open if factors such as lateral preference and/or vestibulo-spinal asymmetry are related to gymnast's rotational preference. Therefore, we sought to explore relationships in gymnast's rotation direction between different gymnastic skills. Furthermore, we sought to explore relationships between rotational preference, lateral preference, and vestibulo-spinal asymmetry. In the experiment n = 30 non-experts, n = 30 near-experts and n = 30 experts completed a rotational preference questionnaire, a lateral preference inventory, and the Unterberger-Fukuda Stepping Test. The results revealed, that near-experts and experts more often rotate rightward in the straight jump with a full turn when rotating leftward in the round-off and vice versa. The same relationship was found for experts when relating the rotation preference in the handstand with a full turn to the rotation preference in the straight jump with a full turn. Lateral preference was positively related to rotational preference in non-expert gymnasts, and vestibulo-spinal asymmetry was positively related to rotational preference in experts. We suggest, that gymnasts should explore their individual rotational preference by systematically practicing different skills with a different rotation direction, bearing in mind that a clearly developed structure in rotational preference between different skills may be appropriate to develop more complex skills in gymnastics. PMID:23486362
Rotational Preference in Gymnastics
Heinen, Thomas; Jeraj, Damian; Vinken, Pia M.; Velentzas, Konstantinos
2012-01-01
In gymnastics, most skills incorporate rotations about one or more body axes. At present, the question remains open if factors such as lateral preference and/or vestibulo-spinal asymmetry are related to gymnast’s rotational preference. Therefore, we sought to explore relationships in gymnast’s rotation direction between different gymnastic skills. Furthermore, we sought to explore relationships between rotational preference, lateral preference, and vestibulo-spinal asymmetry. In the experiment n = 30 non-experts, n = 30 near-experts and n = 30 experts completed a rotational preference questionnaire, a lateral preference inventory, and the Unterberger-Fukuda Stepping Test. The results revealed, that near-experts and experts more often rotate rightward in the straight jump with a full turn when rotating leftward in the round-off and vice versa. The same relationship was found for experts when relating the rotation preference in the handstand with a full turn to the rotation preference in the straight jump with a full turn. Lateral preference was positively related to rotational preference in non-expert gymnasts, and vestibulo-spinal asymmetry was positively related to rotational preference in experts. We suggest, that gymnasts should explore their individual rotational preference by systematically practicing different skills with a different rotation direction, bearing in mind that a clearly developed structure in rotational preference between different skills may be appropriate to develop more complex skills in gymnastics. PMID:23486362
NASA Astrophysics Data System (ADS)
Liu, Jinjun; Melnik, Dmitry; Miller, Terry A.
2013-09-01
The tilde{B} - tilde{X} laser-induced-fluorescence spectrum of jet-cooled isopropoxy radical (i-C3H7O.) has been recorded. Using an isolated state model the observed rotational and fine structure of the origin band has been well simulated to determine rotational constants for both the tilde{X} and tilde{B} states and the electron spin-rotation constants of the tilde{X} state. The line intensities are well simulated with a parallel transition type, requiring the same symmetry for the levels involved of each the tilde{X} and tilde{B} state, which confirms the previous suggestion that going from ethoxy (C2H5O.) to isopropoxy, the energy ordering of the electron configurations with in- and out-of-plane half-filled p-orbitals of the oxygen atom is reversed and the ground vibronic symmetry changes from a″ to a'. However, the observed spin-rotation coupling constants are not consistent with their predication from either semi-empirical theory or quantum chemical calculations. Additionally, the lack of observed transitions involving the out-of-plane transition moment component is not consistent with high level electronic structure calculations suggesting mixing of vibronic levels by strong spin-orbit coupling. A new twofold model has been developed that explicitly includes Coriolis and spin-orbit coupling between different vibronic levels. This model renders the discrepancy between theoretical and experimental spin-rotation constants moot. Moreover, it determines independently the contributions to the observed splitting between the lowest two levels, resulting from non-relativistic kinetic and Coulombic effects, and that due to the relativistic spin-orbit interaction. The experimental values show that these effects are comparable, but that the vibronic one is slightly more important. This result is at variance with state-of-the-art electronic structure calculations which otherwise do a remarkably good job of describing the ground state of isopropoxy.
Accurate calculations of bound rovibrational states for argon trimer
Brandon, Drew; Poirier, Bill
2014-07-21
This work presents a comprehensive quantum dynamics calculation of the bound rovibrational eigenstates of argon trimer (Ar{sub 3}), using the ScalIT suite of parallel codes. The Ar{sub 3} rovibrational energy levels are computed to a very high level of accuracy (10{sup −3} cm{sup −1} or better), and up to the highest rotational and vibrational excitations for which bound states exist. For many of these rovibrational states, wavefunctions are also computed. Rare gas clusters such as Ar{sub 3} are interesting because the interatomic interactions manifest through long-range van der Waals forces, rather than through covalent chemical bonding. As a consequence, they exhibit strong Coriolis coupling between the rotational and vibrational degrees of freedom, as well as highly delocalized states, all of which renders accurate quantum dynamical calculation difficult. Moreover, with its (comparatively) deep potential well and heavy masses, Ar{sub 3} is an especially challenging rare gas trimer case. There are a great many rovibrational eigenstates to compute, and a very high density of states. Consequently, very few previous rovibrational state calculations for Ar{sub 3} may be found in the current literature—and only for the lowest-lying rotational excitations.
Accurate calculations of bound rovibrational states for argon trimer.
Brandon, Drew; Poirier, Bill
2014-07-21
This work presents a comprehensive quantum dynamics calculation of the bound rovibrational eigenstates of argon trimer (Ar3), using the ScalIT suite of parallel codes. The Ar3 rovibrational energy levels are computed to a very high level of accuracy (10(-3) cm(-1) or better), and up to the highest rotational and vibrational excitations for which bound states exist. For many of these rovibrational states, wavefunctions are also computed. Rare gas clusters such as Ar3 are interesting because the interatomic interactions manifest through long-range van der Waals forces, rather than through covalent chemical bonding. As a consequence, they exhibit strong Coriolis coupling between the rotational and vibrational degrees of freedom, as well as highly delocalized states, all of which renders accurate quantum dynamical calculation difficult. Moreover, with its (comparatively) deep potential well and heavy masses, Ar3 is an especially challenging rare gas trimer case. There are a great many rovibrational eigenstates to compute, and a very high density of states. Consequently, very few previous rovibrational state calculations for Ar3 may be found in the current literature-and only for the lowest-lying rotational excitations. PMID:25053315
NASA Astrophysics Data System (ADS)
Greenberg, J.; Guess, C. J.; Tandel, S.; Chowdhury, P.; Carpenter, M. P.; Hartley, D. J.; Janssens, R. V. F.; Khoo, T. L.; Lauritsen, T.; Lister, C. J.; Seweryniak, D.; Shirwadkar, U.; Wang, X.; Zhu, S.
2015-10-01
Studying the structure of rotational bands in 172W is valuable for gaining a better understanding of deformed nuclei. Highly excited states of the isotope were populated from a 230 MeV 50Ti beam incident on a 128Te target at Argonne National Laboratory using the ATLAS accelerator. γ emissions from 172W in the range were measured using Compton suppressed germanium detectors in the Gammasphere array. Using this data, three new rotational bands were found, and several other bands were expanded. Swarthmore College Summer Research Fellowship.
Rotational Cooling of Trapped Polyatomic Molecules
NASA Astrophysics Data System (ADS)
Glöckner, Rosa; Prehn, Alexander; Englert, Barbara G. U.; Rempe, Gerhard; Zeppenfeld, Martin
2015-12-01
Controlling the internal degrees of freedom is a key challenge for applications of cold and ultracold molecules. Here, we demonstrate rotational-state cooling of trapped methyl fluoride molecules (CH3F ) by optically pumping the population of 16 M sublevels in the rotational states J =3 , 4, 5 and 6 into a single level. By combining rotational-state cooling with motional cooling, we increase the relative number of molecules in the state J =4 , K =3 , M =4 from a few percent to over 70%, thereby generating a translationally cold (≈30 mK ) and nearly pure state ensemble of about 106 molecules. Our scheme is extendable to larger sets of initial states, other final states, and a variety of molecule species, thus paving the way for internal-state control of ever-larger molecules.
Rotational Cooling of Trapped Polyatomic Molecules.
Glöckner, Rosa; Prehn, Alexander; Englert, Barbara G U; Rempe, Gerhard; Zeppenfeld, Martin
2015-12-01
Controlling the internal degrees of freedom is a key challenge for applications of cold and ultracold molecules. Here, we demonstrate rotational-state cooling of trapped methyl fluoride molecules (CH_{3}F) by optically pumping the population of 16 M sublevels in the rotational states J=3, 4, 5 and 6 into a single level. By combining rotational-state cooling with motional cooling, we increase the relative number of molecules in the state J=4, K=3, M=4 from a few percent to over 70%, thereby generating a translationally cold (≈30 mK) and nearly pure state ensemble of about 10^{6} molecules. Our scheme is extendable to larger sets of initial states, other final states, and a variety of molecule species, thus paving the way for internal-state control of ever-larger molecules. PMID:26684114
NASA Astrophysics Data System (ADS)
Noda, S.; Ishiwatari, M.; Nakajima, K.; Takahashi, Y. O.; Morikawa, Y.; Nishizawa, S.; Hayashi, Y.-Y.
2012-04-01
In order to investigate a variety of climates of synchronously rotating terrestrial planets, a parameter study on the dependence on planetary rotation rate Ω is performed by using a general circulation model (GCM) with simplified hydrologic and radiative processes. The planetary rotation rate is varied from zero to the Earth's value, and other parameters such as orbital parameters, planetary radius, solar constant are set to the Earth's values. The results show that there emerge four typical atmospheric states in ascending order of planetary rotation rate as follows: States in which dayside-nightside direct circulations dominate States in which weak super rotation emerges States in which strong super rotation emerges and meridionally asymmetric patterns oscillate States in which precipitation disturbances emerge in nightside midlatitudinal regions The atmospheric state is gradually accompanied by a qualitative circulation change from state (1) to state (3) with increasing Ω from zero, although Merlis and Schneider (2010) which performed similar GCM experiments lump together cases with small planetary rotation rates under the term "slowly rotating atmospheres". For cases for planetary rotation rate with the values of 0.75-0.85 times of the terrestrial value, multiple equilibrium solutions of state (3) and state (4) are obtained. It is shown that, in addition to dry atmosphere (Edson et al., 2011), moist atmospheres on synchronously rotating planet also have multiple equilibrium solutions. Although circulation patterns and amount of sensible/latent heat transport from the dayside to the nightside changes with the change of Ω, summation of sensible heat transport and latent heat transport almost remains unchanged, and the dependence of dayside to nightside temperature contrast on Ω is small.
Lorbach, Andreas; Maverick, Emily; Carreras, Abel; Alemany, Pere; Wu, Guang; Garcia-Garibay, Miguel A; Bazan, Guillermo C
2014-07-01
A new fullerene structure was recently obtained from the reaction of a Lewis basic N-heterocyclic carbene (NHC) and the Lewis acidic C60. The molecular features of the zwitterionic adduct can be described as a molecular rotor with the fullerene cage acting as the rotator that spins about one distinct axis given by its C-C single bond linkage with the imidazolium heterocycle stator. A detailed structural analysis of the compound by means of single-crystal X-ray diffraction (XRD) revealed significant differences in the packing motifs of solvent-free and solvent-containing crystals. Variable temperature single-crystal XRD experiments (80 K ≤ T ≤ 480 K) carried out to investigate the rotational dynamics of the fullerene group in the higher quality solvent-free structure revealed atomic displacement parameters consistent with fast rotation of the highly symmetric fullerene in the solid state, whereas the imidazolium unit remains in a fixed position and therefore represents the stator. DFT and semiempirical calculations were applied to get insight into the profile of the rotational potential of the fullerene unit, particularly considering interactions with the neighboring molecules in the crystal lattice. The results indicate that the crystal environment leads to the presence of one lowest energy minimum that is connected to seven others that are slightly higher in energy through rotational barriers of approximately 1.5-2.5 kcal mol(-1). PMID:24852314
Intraplate rotational deformation induced by faults
NASA Astrophysics Data System (ADS)
Dembo, Neta; Hamiel, Yariv; Granot, Roi
2015-11-01
Vertical axis rotations provide important constraints on the tectonic history of plate boundaries. Geodetic measurements can be used to calculate interseismic rotations, whereas paleomagnetic remanence directions provide constraints on the long-term rotations accumulated over geological timescales. Here we present a new mechanical modeling approach that links between intraplate deformational patterns of these timescales. We construct mechanical models of active faults at their locked state to simulate the presumed to be elastic interseismic deformation rate observed by GPS measurements. We then apply a slip to the faults above the locking depth to simulate the long-term deformation of the crust from which we derive the accumulated rotations. We test this approach in northern Israel along the Dead Sea Fault and Carmel-Gilboa fault system. We use 12 years of interseismic GPS measurements to constrain a slip model of the major faults found in this region. Next, we compare the modeled rotations against long-term rotations determined based on new primary magnetic remanence directions from 29 sites with known age. The distributional pattern of site mean declinations is in general agreement with the vertical axis rotations predicted by the mechanical model, both showing anomalously high rotations near fault tips and bending points. Overall, the results from northern Israel validate the effectiveness of our approach and indicate that rotations induced by motion along faults may act in parallel (or alone) to rigid block rotations. Finally, the new suggested method unravels important insights on the evolution (timing, magnitude, and style) of deformation along major faults.
The rotation of the Sun's core.
NASA Astrophysics Data System (ADS)
Paterno, L.; Sofia, S.; di Mauro, M. P.
1996-10-01
The rotation of the Sun's core, below 0.3Rsun_, is inferred from two independent new results. The first is based on the recent oblateness measurements carried out by the Solar Disk Sextant (SDS) instrument outside the Earth's atmosphere, and the second on the very accurate measurements of rotational splittings of the lowest degree acoustic modes, carried out in the framework of the helioseismic network IRIS. By using the theory of slowly rotating stars applied to a solar standard model, we deduce a set of rotational laws for the innermost layers, which are consistent with both the measured oblateness value and the results of the inversion of helioseismic data. The SDS and IRIS results indicate that the Sun's central regions rotate at a rate in between 1.5 and 2 times the surface equatorial angular velocity. As a result of our analysis, we deduce a quadrupole moment J_2_=2.22x10^-7^, which implies an advance of Mercury's perihelion of 42.98arcsec/c, in agreement with the theory of General Relativity and the measurements of Mercury's orbit by means of planetary radar ranging. However, very recent results obtained by the helioseismic network BISON indicate that core rotation is even slower than the polar surface rotation and therefore imply a completely different scenario than that proposed here. If we assume the intermediate solution of rigid body rotation, an alternate source of the oblateness may be attributed to a magnetic field of the order of 10^5^Gauss in the interior of the Sun.
Ahmad, I.; Sjoblom, R.K.
1980-09-01
Low-spin states of /sup 250/Cf have been investigated by measuring ..gamma.. rays and conversion electrons associated with the electron capture decay of 2.22-h /sup 250/Es. Mass-separated /sup 250/Es samples produced by the /sup 249/Cf(d,n) reaction were used for these measurements. The ..gamma..-ray spectra were measured with a 25-cm/sup 3/ coaxial Ge(Li) spectrometer and the electron spectra were measured with a cooled Si(Li) detector. Multipolarities of intense transitions in /sup 250/Cf were deduced and logft values of electron capture transitions were derived from measured electron capture intensities. On the basis of the results of the present investigation the following bandheads were identified in /sup 250/Cf: E (keV),K,I..pi..=871.6, 2,2-; 1031.9, 2,2+; 1154.2, 0,0+; 1175.5, 1,1-; 1210.0, 2,2-; 1244.4, 2,2+; 1266.5, 0,0+; and 1658.1, 2,2+. The 2.22-h state in /sup 250/Es has been given a spin-parity assignment of 1- with configuration )n(734)9/2-; p(633)7/2+)/sub 1//sub -/.
Power Harvesting from Rotation?
ERIC Educational Resources Information Center
Chicone, Carmen; Feng, Z. C.
2008-01-01
We show the impossibility of harvesting power from rotational motions by devices attached to the rotating object. The presentation is suitable for students who have studied Lagrangian mechanics. (Contains 2 figures.)
A search for the lowest-energy conformer of interstellar glycine
NASA Technical Reports Server (NTRS)
Hollis, J. M.; Snyder, L. E.; Suenram, R. D.; Lovas, F. J.
1980-01-01
The first search for the lowest-energy conformation of interstellar glycine has been carried out. An emission line has been detected in Sgr B2 which is coincident in frequency with the J(K-K+) = 14(1, 14)-13(1, 13) transition of conformer I glycine; while the carrier of the observed line is uncertain, no other frequency-coincident species are known, and hence glycine cannot be ruled out. Several previously unidentified lines have been identified as methyl formate. Evidence for the existence of the elusive interstellar ethylene oxide, the only reported interstellar ring-structure molecule, is discussed.
Evidence for limits on the acceptability of lowest-tar cigarettes.
Kozlowski, L T
1989-01-01
The sales of the lowest yield cigarettes (1-3 mg tar) seem to have been particularly resistant to the effects of promotion and advertising, while the sales of other low-yield cigarettes (4-9 mg tar) seem to have been increased by promotional efforts. This finding is consistent with the existence of a boundary of tar and nicotine acceptability below which consumers in general are not prepared to go. Use of lower tar cigarettes may be helpful for those who cannot stop smoking, but, since 1979, the percentage of cigarettes under 16 mg tar has changed little. PMID:2913841
Measurement of the lowest millimeter-wave transition frequency of the CH radical
Truppe, S.; Hendricks, R. J.; Hinds, E. A.; Tarbutt, M. R.
2014-01-01
The CH radical offers a sensitive way to test the hypothesis that fundamental constants measured on Earth may differ from those observed in other parts of the universe. The starting point for such a comparison is to have accurate laboratory frequencies. Here, we measure the frequency of the lowest millimeter-wave transition of CH, near 535 GHz, with an accuracy of 0.6 kHz. This improves the uncertainty by roughly two orders of magnitude over previous determinations and opens the way for sensitive new tests of varying constants.
Lowest order QED radiative corrections to longitudinally polarized Møller scattering
NASA Astrophysics Data System (ADS)
Ilyichev, A.; Zykunov, V.
2005-08-01
The total lowest-order electromagnetic radiative corrections to the observables in Møller scattering of longitudinally polarized electrons have been calculated. The final expressions obtained by the covariant method for the infrared divergency cancellation are free from any unphysical cut-off parameters. Since the calculation is carried out within the ultrarelativistic approximation our result has a compact form that is convenient for computing. Basing on these expressions the FORTRAN code MERA has been developed. Using this code the detailed numerical analysis performed under SLAC (E-158) and JLab kinematic conditions has shown that the radiative corrections are significant and rather sensitive to the value of the missing mass (inelasticity) cuts.
Rubio, Mercedes; Roca-Sanjuan, Daniel; Merchan, Manuela; Serrano-Andrés, Luis
2006-06-01
High level ab initio computations anticipate nucleobases as the most favorable sites for oxidation in nucleotides. At the CASPT2 level, the lowest ionization channel for the 2'-deoxythymidine 5'-monophosphate anion is related to a pi-orbital of the thymine base. The present findings lead to revision of the recent assignments of the photodetachment photoelectron spectra of mononucleotide anions in the gas phase and support the classical view of the nucleobase being the main actor in the oxidation process of both nucleosides and nucleotides. PMID:16722723
carlomat, version 2 of the program for automatic computation of lowest order cross sections
NASA Astrophysics Data System (ADS)
Kołodziej, Karol
2014-01-01
Version 2 of carlomat, a program for automatic computation of the lowest order cross sections of multiparticle reactions, is described. The substantial modifications with respect to version 1 of the program include: generation of a single phase space parameterization for the Feynman diagrams of the same topology, an interface to parton density functions, improvement of the color matrix computation, the Cabibbo-Kobayashi-Maskawa mixing in the quark sector, the effective models including scalar electrodynamics, the Wtb interaction with operators of dimension up to 5 and a general top-Higgs coupling. Moreover, some minor modifications have been made and several bugs in the program have been corrected.
Chiral symmetry in rotating systems
NASA Astrophysics Data System (ADS)
Malik, Sham S.
2015-08-01
The triaxial rotating system at critical angular momentum I ≥Iband exhibits two enatiomeric (the left- and right-handed) forms. These enatiomers are related to each other through dynamical chiral symmetry. The chiral symmetry in rotating system is defined by an operator χ ˆ =Rˆy (π) T ˆ, which involves the product of two distinct symmetries, namely, continuous and discrete. Therefore, new guidelines are required for testing its commutation with the system Hamiltonian. One of the primary objectives of this study is to lay down these guidelines. Further, the possible impact of chiral symmetry on the geometrical arrangement of angular momentum vectors and investigation of observables unique to nuclear chiral-twins is carried out. In our model, the angular momentum components (J1, J2, J3) occupy three mutually perpendicular axes of triaxial shape and represent a non-planar configuration. At certain threshold energy, the equation of motion in angular momentum develops a second order phase transition and as a result two distinct frames (i.e., the left- and right-handed) are formed. These left- and right-handed states correspond to a double well system and are related to each other through chiral operator. At this critical angular momentum, the centrifugal and Coriolis interactions lower the barrier in the double well system. The tunneling through the double well starts, which subsequently lifts the degeneracy among the rotational states. A detailed analysis of the behavior of rotational energies, spin-staggering, and the electromagnetic transition probabilities of the resulting twin-rotational bands is presented. The ensuing model results exhibit similarities with many observed features of the chiral-twins. An advantage of our formalism is that it is quite simple and it allows us to pinpoint the understanding of physical phenomenon which lead to chiral-twins in rotating systems.
DESIGN INFORMATION ON ROTATING BIOLOGICAL CONTACTORS
The relatively rapid introduction of rotating biological contactors (RBC's) into the United States for municipal wastewater treatment has resulted in the widespread application of a technology with which many design engineers are not intimately familiar. Of necessity, many RBC de...
Evolutionary optimization of rotational population transfer
Rouzee, Arnaud; Vrakking, Marc J. J.; Ghafur, Omair; Gijsbertsen, Arjan; Vidma, Konstantin; Meijer, Afric; Zande, Wim J. van der; Parker, David; Shir, Ofer M.; Baeck, Thomas
2011-09-15
We present experimental and numerical studies on control of rotational population transfer of NO(J=1/2) molecules to higher rotational states. We are able to transfer 57% of the population to the J=5/2 state and 46% to J=9/2, in good agreement with quantum mechanical simulations. The optimal pulse shapes are composed of pulse sequences with delays corresponding to the beat frequencies of states on the rotational ladder. The evolutionary algorithm is limited by experimental constraints such as volume averaging and the finite laser intensity used, the latter to circumvent ionization. Without these constraints, near-perfect control (>98%) is possible. In addition, we show that downward control, moving molecules from high to low rotational states, is also possible.
Pirali, O.; Gruet, S.; Kisiel, Z.; Martin-Drumel, M. A.; Cuisset, A.; Hindle, F.; Mouret, G.
2015-03-14
Polycyclic aromatic hydrocarbons (PAHs) are highly relevant for astrophysics as possible, though controversial, carriers of the unidentified infrared emission bands that are observed in a number of different astronomical objects. In support of radio-astronomical observations, high resolution laboratory spectroscopy has already provided the rotational spectra in the vibrational ground state of several molecules of this type, although the rotational study of their dense infrared (IR) bands has only recently become possible using a limited number of experimental set-ups. To date, all of the rotationally resolved data have concerned unperturbed spectra. We presently report the results of a high resolution study of the three lowest vibrational states of quinoline C{sub 9}H{sub 7}N, an N-bearing naphthalene derivative. While the pure rotational ground state spectrum of quinoline is unperturbed, severe complications appear in the spectra of the ν{sub 45} and ν{sub 44} vibrational modes (located at about 168 cm{sup −1} and 178 cm{sup −1}, respectively). In order to study these effects in detail, we employed three different and complementary experimental techniques: Fourier-transform microwave spectroscopy, millimeter-wave spectroscopy, and Fourier-transform far-infrared spectroscopy with a synchrotron radiation source. Due to the high density of states in the IR spectra of molecules as large as PAHs, perturbations in the rotational spectra of excited states should be ubiquitous. Our study identifies for the first time this effect and provides some insights into an appropriate treatment of such perturbations.
Rotations with Rodrigues' Vector
ERIC Educational Resources Information Center
Pina, E.
2011-01-01
The rotational dynamics was studied from the point of view of Rodrigues' vector. This vector is defined here by its connection with other forms of parametrization of the rotation matrix. The rotation matrix was expressed in terms of this vector. The angular velocity was computed using the components of Rodrigues' vector as coordinates. It appears…
Mechanism of rotational relaxation.
NASA Technical Reports Server (NTRS)
Polanyi, J. C.; Woodall, K. B.
1972-01-01
A model is presented which describes the characteristic pattern of relaxation of a nonthermal rotational distribution of hydrogen halide, peaked initially at high rotational quantum number J, to a thermal distribution without generating a peak at intermediate J. A method for correcting infrared chemiluminiscence data for modest rotational relaxation is also suggested.
NASA Astrophysics Data System (ADS)
Storm, V.; Dreizler, H.; Consalvo, D.
1998-12-01
This study is supplementary to our previous work on the benzonitrile-water complex, and provides more detailed information on the heavy atom structure of this hydrogen bonded system. Here the analysis of two additional isotopomer spectra of the 15N-substituted benzonitrile complexed with 16O- and 18O-water confirms that there is one near planar structure compatible with the twelve moments of inertia. This structure is ring-like with two hydrogen bonds, having a O⋯H bond length of 2.472(3) Å, and a N⋯H bond length of 2.66(2) Å. A narrow splitting of the μb-transitions was interpreted to be caused by an internal rotation of the water subunit. A mean value for the twofold barrier height V2=467(9) cm -1 was also determined.
Technology Transfer Automated Retrieval System (TEKTRAN)
Labor and profitability associated with continuous grazing at three stocking rates and rotational grazing at a high stocking rate are compared. Profits are lowest for low stocking rate continuous grazing and high stocking rate rotational grazing. Labor is greatest on per-acre and per-cow basis wit...
Instabilities of rare rotating cold molecular clouds
Nekrasov, A. K.
2009-03-15
New electromagnetic streaming instabilities of rare rotating molecular clouds induced by the relative drift of ions, electrons, and dust grains in the equilibrium state are studied. The cases of a weak and strong collisional coupling of neutrals and ions in the perturbed state are involved. The dust grains are considered as unmagnetized having weak collisional coupling with neutrals in perturbations. The compressibility is taken into account. Axisymmetric perturbations with growth rates much larger than the rotation frequency are found.
NASA Astrophysics Data System (ADS)
Ding, H. L.; He, Y. Z.; Liu, L. F.; Ding, W. J.
2006-08-01
The microstructure and morphology evolution of grain growth were studied by 3D simulation using the cellular automata (CA) model based on the lowest-energy principle. In the present CA model, the transition of cells during the grain growth has a typical physical meaning due to the application of the lowest-energy principle. The results show that the kinetics of grain growth follows Burke equation with the growth exponent as 2. The average number of grain faces is 13.6 and the highest frequency of grain faces is 10 faces. The grain size distribution follows Weibull function. The relationship between the number of faces of a grain and the average number of faces of its adjacent grains follows the Aboav-Weaire law. There is a correlation between the topologies of the simulated 2D and 3D grain growth. The average number of sides per face for all grains is 5.65 and the average number of sides per face is about equal to 6 when the grain aces is larger than 35.
Selecting the column configuration with lowest media replacement cost for small adsorption systems.
Bausk, Artem S; Dvorak, Bruce I
2016-04-15
A framework was developed for preliminary evaluation of the relative media replacement costs of three alternative column configurations used for adsorption systems with two vessels, such as those serving small systems. The media replacement cost is the cost of fresh media and the replacement service cost (including transportation, labor, and other non-material costs). Cost normalization methods were developed in part based on the data from US EPA Arsenic Treatment Technology Demonstration Program. Adsorption equilibrium and kinetics were modeled using the PSDM model and breakthrough curves were normalized using the target effluent to influent concentration ratio (C/Co) and the mass transfer zone fraction (%MTZBT). Two factors were found to be important for the relative replacement cost of each configuration - the frequency which at least one column needed replacement of media, and the cycle replacement cost (CRCost) which is a combination of the fresh media cost and the replacement service cost. The lead-lag configuration has the lowest annual replacement cost at low target C/Co, high %MTZBT, and high CRCost ratios. The parallel configuration performs better at high target C/Co, high %MTZBT, and high CRCost ratios. Although the single configuration (two columns operated in tandem and replaced simultaneously) has higher media consumption compared to lead-lag and parallel, it can result in the lowest replacement cost at short %MTZBT and very low CRCost ratios due to savings in the replacement service cost. PMID:26894474
Hattori, Koichi; Itakura, Kazunori
2013-07-15
We compute the refractive indices of a photon propagating in strong magnetic fields on the basis of the analytic representation of the vacuum polarization tensor obtained in our previous paper. When the external magnetic field is strong enough for the fermion one-loop diagram of the polarization tensor to be approximated by the lowest Landau level, the propagating mode in parallel to the magnetic field is subject to modification: The refractive index deviates from unity and can be very large, and when the photon energy is large enough, the refractive index acquires an imaginary part indicating decay of a photon into a fermion–antifermion pair. We study dependences of the refractive index on the propagating angle and the magnetic-field strength. It is also emphasized that a self-consistent treatment of the equation which defines the refractive index is indispensable for accurate description of the refractive index. This self-consistent treatment physically corresponds to consistently including the effects of back reactions of the distorted Dirac sea in response to the incident photon. -- Highlights: •Vacuum birefringence and photon decay are described by the complex refractive index. •Resummed photon vacuum polarization tensor in the lowest Landau level is used. •Back reactions from the distorted Dirac sea are self-consistently taken into account. •Self-consistent treatment drastically changes structure in photon energy dependence. •Dependences on photon propagation angle and magnetic-field strength are presented.
Network of dedicated processors for finding lowest-cost map path
NASA Technical Reports Server (NTRS)
Eberhardt, Silvio P. (Inventor)
1991-01-01
A method and associated apparatus are disclosed for finding the lowest cost path of several variable paths. The paths are comprised of a plurality of linked cost-incurring areas existing between an origin point and a destination point. The method comprises the steps of connecting a purality of nodes together in the manner of the cost-incurring areas; programming each node to have a cost associated therewith corresponding to one of the cost-incurring areas; injecting a signal into one of the nodes representing the origin point; propagating the signal through the plurality of nodes from inputs to outputs; reducing the signal in magnitude at each node as a function of the respective cost of the node; and, starting at one of the nodes representing the destination point and following a path having the least reduction in magnitude of the signal from node to node back to one of the nodes representing the origin point whereby the lowest cost path from the origin point to the destination point is found.
Rotational rainbows in electron-molecule scattering
Ziegler, G.; Raedle, M.; Puetz, O.; Jung, K.; Ehrhardt, H.; Bergmann, K.
1987-06-22
We report the measurement of state-to-state differential cross sections for rotationally inelastic electron-Na/sub 2/ collisions for impact energies from 150 to 300 eV. The data demonstrate for the first time large rotational transitions (0less than or equal to..delta..jless than or equal to30) for backward scattering. The most surprising result is the observation of pronounced rotational rainbows. These structures are expected to be general features in high-energy electron-molecule scattering.
NASA Astrophysics Data System (ADS)
Dattani, Nikesh S.; Li, Xuan
2013-06-01
Recent high-resolution (± 0.00002 cm^{-1}) photo-association spectroscopy (PAS) data of seven previously unexplored vibrational levels of the 1^3Σ_g^+ state of Li_2 have allowed for the first ever experimental determination of the spin-spin (λ_v) and spin-rotation (γ_v) coupling constants in a diatomic lithium system. For triplet states of diatomic molecules such as the 1^3Σ_g^+ state of Li_2, the three spin-spin/spin-rotation resolved energies associated with a ro-vibrational state |v,N> were expressed explicity in terms of B_v, λ_v, and γ_v in 1929 by Kramer's first-order formulas and then in 1937 by Schlapp's more refined formulas. Given spectroscopic data, while it has never been difficult to extract λ_v and γ_v from Schlapp's formulas, it has been a challenge to reliably predict how accurate these extracted values are. This is for two reasons: (1) the lack of a rigorous method to estimate the uncertainty in B_v, (2) the non-linearity of Schlapp's coupled equations has meant that traditionally they have had to be solved numerically by Newton iterations which makes error propagation difficult. The former challenge has been this year solved by Le Roy with a modification of Hutson's perturbation theory of, and the latter problem has now been solved by symbolic computing software that solves Schlapp's coupled non-linear equations analytically for the first time since their introduction in 1937. M. Semczuk, X. Li, W. Gunton, M. Haw, N. Dattani, J. Witz, A. Mills, D. Jones, K. Madison, Physical Review A {87}, XX (2013) H. Kramers, Zeitschrift fur Physik {53}, 422 (1929) R. Schlapp, Physical Review {51}, 342 (1937) J. Hutson, J. Phys. B, {14}, 851 (1981)
Coffman, R.T.
1957-12-10
A seal is described for a rotatable shaft that must highly effective when the shaft is not rotating but may be less effective while the shaft is rotating. Weights distributed about a sealing disk secured to the shaft press the sealing disk against a tubular section into which the shiilt extends, and whem the shaft rotates, the centrifugal forces on the weights relieve the pressurc of the sealing disk against the tubular section. This action has the very desirible result of minimizing the wear of the rotating disk due to contact with the tubular section, while affording maximum sealing action when it is needed.
Vortex formation in a fast rotating Bose-Einstein condensate
Ghosh, Tarun Kanti
2004-04-01
We study rotational motion of an interacting atomic Bose-Einstein condensate confined in a quadratic-plus-quartic potential. We calculate the lowest energy surface mode frequency and show that a symmetric trapped (harmonic and quartic) Bose-Einstein condensate breaks the rotational symmetry of the Hamiltonian when rotational frequency is greater than one-half of the lowest energy surface mode frequency. We argue that the formation of a vortex is not possible in a noninteracting as well as in an attractive Bose-Einstein condensate confined in a harmonic trap due to the absence of the spontaneous shape deformation, but it can occur which leads to the vortex formation if we add an additional quartic potential. Moreover, the spontaneous shape deformation and consequently the formation of a vortex in an attractive system depends on the strengths of the two-body interaction and the quartic potential.
Reports on block rotations, fault domains and crustal deformation
NASA Technical Reports Server (NTRS)
Nur, Amos
1990-01-01
Studies of block rotations, fault domains and crustal deformation in the western United States, Israel, and China are discussed. Topics include a three-dimensional model of crustal fracture by distributed fault sets, distributed deformation and block rotation in 3D, stress field rotation, and multiple strike slip fault sets.
Analytical theory of strongly correlated Wigner crystals in the lowest Landau level
NASA Astrophysics Data System (ADS)
Rhim, Jun-Won; Jain, Jainendra K.; Park, Kwon
2015-09-01
In this work, we present an analytical theory of strongly correlated Wigner crystals (WCs) in the lowest Landau level (LLL) by constructing an approximate, but accurate effective two-body interaction for composite fermions (CFs) participating in the WCs. This requires integrating out the degrees of freedom of all surrounding CFs, which we accomplish analytically by approximating their wave functions by delta functions. This method produces energies of various strongly correlated WCs that are in excellent agreement with those obtained from the Monte Carlo simulation of the full CF crystal wave functions. We compute the compressibility of the strongly correlated WCs in the LLL and predict discontinuous changes at the phase boundaries separating different crystal phases.
Detecting the lowest-energy structures of CAu16q(q=-1,0)
NASA Astrophysics Data System (ADS)
Fa, Wei; Yang, Aping
2008-10-01
Using scalar relativistic density-functional simulations, we have performed a detailed study of the structural and electronic properties of CAu16q(q=-1,0). We have discovered that the most stable configurations of both the neutral and anionic C-doped gold clusters are not endohedral structures but distorted close-flat cages, in which the carbon atom prefers forming covalent bonds with its four nearest-neighboring gold atoms. Despite the geometrical similarity between the CAu 4 and SiAu 4, the lowest-energy CAu16q(q=-1,0) show a square-pyramid local structure around the dopant carbon just like the cases of GeAu16- and SnAu16-, displaying different photoelectron spectroscopy with those of isomers with a dangling gold atom atop carbon.
Wigner-crystallization of Rydberg-Polaritons in the lowest Landau level
NASA Astrophysics Data System (ADS)
Grusdt, Fabian; Fleischhauer, Michael
2012-02-01
For electrons and dipolar fermions in the lowest Landau level the critical filling for Wigner-crystallization was shown to be νc 1/7 [Baranov et. al., Phys. Rev. Lett. 100 (2008)]. We investigate the fractional quantum Hall effect for Van-der-Waals interacting bosons as realized e.g. by stationary-light polaritons in a Rydberg gas and find no transition to the Wigner crystal (WC). Our numerical studies suggest a crystalline groundstate below ν=1/6 which is expected to be described by a correlated WC of composite quasiparticles. Taking into account a cut-off in the Van-der-Waals interaction we find the WC to be favorable for large cut-offs. Numerical results for different geometries are presented and realistic implementations are discussed.
Bid distribution derived from consistent mixed strategy in lowest unique bid auction
NASA Astrophysics Data System (ADS)
Zhao, Yinan; Chen, Qinghua; Wang, Yougui
2014-12-01
The Lowest Unique Bid Auction (LUBA) booms recently through the Internet. A typical distribution pattern of bid price in this reverse auction has been found and needs to be interpreted. The distribution curve is a decreasing one whose slope has a close relationship with the number of agents participating in the auction. To explain this stylized fact, we develop a model assuming that agents prefer to bid on the price at which the probability of winning is higher. The bid distributions of actual auctions with the number of agents less than 200 can be fitted very well using the parameters for the value of items and the number of bids. When this number becomes larger, however, a deviation occurs between prediction and empirical data, which can be adjusted by introducing cognitive illusion of the bid number.
Esselman, Brian J; Amberger, Brent K; Shutter, Joshua D; Daane, Mitchell A; Stanton, John F; Woods, R Claude; McMahon, Robert J
2013-12-14
The rotational spectrum of pyridazine (o-C4H4N2), the ortho disubstituted nitrogen analog of benzene, has been measured and analyzed in the gas phase. For the ground vibrational state of the normal isotopolog, over 2000 individual rotational transitions have been identified between 238 and 360 GHz and have been fit to 13 parameters of a 6th-order centrifugal distortion Hamiltonian. All transitions in this frequency region can now be predicted from this model to near experimental accuracy, i.e., well enough for the purpose of any future radio-astronomical search for this species. Three isotopologs, [3-(13)C]-C4H4N2, [4-(13)C]-C4H4N2, and [1-(15)N]-C4H4N2, have been detected in natural abundance, and several hundred lines have been measured for each of these species and fit to 6th-order Hamiltonians. Ten additional isotopologs were synthesized with enhanced deuterium substitution and analyzed to allow for a complete structure determination. The equilibrium structure (Re) of pyridazine was obtained by correcting the experimental rotational constants for the effects of vibration-rotation coupling using interaction constants predicted from CCSD(T) calculations with an ANO0 basis set and further correcting for the effect of electron mass. The final Re structural parameters are determined with excellent accuracy, as evidenced by their ability to predict 28 independent moments of inertia (Ia and Ib for 14 isotopologs) very well from 9 structural parameters. The rotational spectra of the six lowest-energy fundamental vibrational satellites of the main isotopolog have been detected. The rotational spectra of the five lowest-energy vibrational satellites have been assigned and fit to yield accurate rotational and distortion constants, while the fit and assignment for the sixth is less complete. The resultant vibration-rotation interaction (α) constants are found to be in excellent agreement with ones predicted from coupled-cluster calculations, which proved to be the key
Esselman, Brian J.; Amberger, Brent K.; Shutter, Joshua D.; Daane, Mitchell A.; Woods, R. Claude; McMahon, Robert J.; Stanton, John F.
2013-12-14
The rotational spectrum of pyridazine (o-C{sub 4}H{sub 4}N{sub 2}), the ortho disubstituted nitrogen analog of benzene, has been measured and analyzed in the gas phase. For the ground vibrational state of the normal isotopolog, over 2000 individual rotational transitions have been identified between 238 and 360 GHz and have been fit to 13 parameters of a 6th-order centrifugal distortion Hamiltonian. All transitions in this frequency region can now be predicted from this model to near experimental accuracy, i.e., well enough for the purpose of any future radio-astronomical search for this species. Three isotopologs, [3-{sup 13}C]-C{sub 4}H{sub 4}N{sub 2}, [4-{sup 13}C]-C{sub 4}H{sub 4}N{sub 2}, and [1-{sup 15}N]-C{sub 4}H{sub 4}N{sub 2}, have been detected in natural abundance, and several hundred lines have been measured for each of these species and fit to 6th-order Hamiltonians. Ten additional isotopologs were synthesized with enhanced deuterium substitution and analyzed to allow for a complete structure determination. The equilibrium structure (R{sub e}) of pyridazine was obtained by correcting the experimental rotational constants for the effects of vibration-rotation coupling using interaction constants predicted from CCSD(T) calculations with an ANO0 basis set and further correcting for the effect of electron mass. The final R{sub e} structural parameters are determined with excellent accuracy, as evidenced by their ability to predict 28 independent moments of inertia (I{sub a} and I{sub b} for 14 isotopologs) very well from 9 structural parameters. The rotational spectra of the six lowest-energy fundamental vibrational satellites of the main isotopolog have been detected. The rotational spectra of the five lowest-energy vibrational satellites have been assigned and fit to yield accurate rotational and distortion constants, while the fit and assignment for the sixth is less complete. The resultant vibration-rotation interaction (α) constants are found to
NASA Astrophysics Data System (ADS)
Moule, D. C.; Smeyers, Y. G.; Senent, M. L.; Clouthier, D. J.; Karolczak, J.; Judge, R. H.
1991-09-01
Jet-cooled, laser-induced phosphorescence excitation spectra (LIP) of thioacetone (CH3)2CS/(CD3)2CS have been recorded over the region 16 800-18 500 cm-1 using the pyrolysis jet spectroscopic technique. The responsible electronic transition, T1←S0, ã 3A`←X˜ 1A1, results from an n→π* electron promotion and gives rise to a pattern of vibronic bands that were attributed to activity of the methyl torsion and the sulphur out-of-plane wagging modes. The intensities of the torsional and wagging progressions in the excitation spectra were interpreted in terms of a C2v-Cs molecular distortion of the triplet molecule from its singlet ground state equilibrium structure. A complete unrestricted Hartree-Fock (UHF) ab initio molecular orbital (MO) structural optimization of the T1 state predicted that the sulphur was displaced by 27.36° from the molecular plane and the methyl groups were rotated by 10.93° in clockwise-counterclockwise directions. Restricted Hartree-Fock (RHF) calculations were used to generate the V(θ1,θ2) potential surface governing methyl rotation for the S0 state. This was incorporated into a two-dimensional Hamiltonian, symmetrized for the G36 point group and solved variationally for the torsional frequencies. The calculated frequencies of 159.97/118.94 for the ν17(b1) mode of S0 (CH3)2CS/(CD3)2CS were found to agree with the experimental values, 153.2/114.7 cm-1.
NASA Astrophysics Data System (ADS)
Mikheev, S. A.; Tsvetkov, V. P.
2016-07-01
A system of equations and inequalities that allows one to determine the constraints on central density ρ c and the chemical composition, which is governed by parameter μ e , of the white dwarf RX J0648.0- 4418 with a record short period of rotation T = 13.18s and mass m = (1.28 ± 0.05) m⊙, has been derived. The analysis of numerical solutions of this system reveal a complex dependence of μ e on ρ c . The intervals of variation of μ e and ρ c are as follows: 1.09 ≤ μ e ≤ 1.21 and 9.04 ≤ μ e /ρ0 ≤ 103 (ρ0 = 0.98 × 106 g/cm3). This range of μ e values suggests that the white dwarf RX J0648.0-4418 is not made of pure hydrogen and should contain 9-21% of heavy elements. Calculations have been performed with the equation of state of an ideal degenerate electron gas. Approximate analytic expressions (with an accuracy of 10-3) for the minimum period T min and mass m of the white dwarf are obtained. It is demonstrated that the white-dwarf mass is almost doubled (compared to the case of no rotation at a fixed central density) as period T approaches T min.
Ruiz-Gonzalez, Ruben; Gomez-Gil, Jaime; Gomez-Gil, Francisco Javier; Martínez-Martínez, Víctor
2014-01-01
The goal of this article is to assess the feasibility of estimating the state of various rotating components in agro-industrial machinery by employing just one vibration signal acquired from a single point on the machine chassis. To do so, a Support Vector Machine (SVM)-based system is employed. Experimental tests evaluated this system by acquiring vibration data from a single point of an agricultural harvester, while varying several of its working conditions. The whole process included two major steps. Initially, the vibration data were preprocessed through twelve feature extraction algorithms, after which the Exhaustive Search method selected the most suitable features. Secondly, the SVM-based system accuracy was evaluated by using Leave-One-Out cross-validation, with the selected features as the input data. The results of this study provide evidence that (i) accurate estimation of the status of various rotating components in agro-industrial machinery is possible by processing the vibration signal acquired from a single point on the machine structure; (ii) the vibration signal can be acquired with a uniaxial accelerometer, the orientation of which does not significantly affect the classification accuracy; and, (iii) when using an SVM classifier, an 85% mean cross-validation accuracy can be reached, which only requires a maximum of seven features as its input, and no significant improvements are noted between the use of either nonlinear or linear kernels. PMID:25372618
Ruiz-Gonzalez, Ruben; Gomez-Gil, Jaime; Gomez-Gil, Francisco Javier; Martínez-Martínez, Víctor
2014-01-01
The goal of this article is to assess the feasibility of estimating the state of various rotating components in agro-industrial machinery by employing just one vibration signal acquired from a single point on the machine chassis. To do so, a Support Vector Machine (SVM)-based system is employed. Experimental tests evaluated this system by acquiring vibration data from a single point of an agricultural harvester, while varying several of its working conditions. The whole process included two major steps. Initially, the vibration data were preprocessed through twelve feature extraction algorithms, after which the Exhaustive Search method selected the most suitable features. Secondly, the SVM-based system accuracy was evaluated by using Leave-One-Out cross-validation, with the selected features as the input data. The results of this study provide evidence that (i) accurate estimation of the status of various rotating components in agro-industrial machinery is possible by processing the vibration signal acquired from a single point on the machine structure; (ii) the vibration signal can be acquired with a uniaxial accelerometer, the orientation of which does not significantly affect the classification accuracy; and, (iii) when using an SVM classifier, an 85% mean cross-validation accuracy can be reached, which only requires a maximum of seven features as its input, and no significant improvements are noted between the use of either nonlinear or linear kernels. PMID:25372618
Global Rotation of Non-Rotating Origin
NASA Astrophysics Data System (ADS)
Fukushima, T.
2001-11-01
At its 24th General Assembly held at Manchester last year, the IAU has adopted the Celestial Ephemeris Origin (CEO) as a new longitude origin of the celestial coordinate system (Capitaine et al. 2000, IAU 2001). The CEO is the application of Guinot's non-rotating origin (NRO) to the Earth's equator (Guinot 1979, Capitaine et al. 1986, Capitaine 1990). By using the current IAU precession/nutation theory, we integrated the global orbit of CEO. It is a slightly curved zigzag pattern of the amplitude of around 23o moving secularly along the ecliptic. Among its kinematical features, we note that CEO has a large secular component of rotation with respect to the inertial reference frame. The current speed of this global rotation is as large as around -4.15 ''/yr. The negative sign shows that CEO rotates clockwise with respect to the inertial frame when viewed from the north celestial pole. Unfortunately this is a general property of NROs. On the other hand, such secular rotation does not exist for some geometrically-defined longitude origins like K, H, and Σ already discussed in Kovalevsky and McCarthy (1998). We think that the existence of a global secular rotaion means that the CEO, and NROs in general, is not appropriate to be specified as the x-axis of celestial coordinate systems.
NASA Astrophysics Data System (ADS)
Shimizu, Yusei; Kittaka, Shunichiro; Sakakibara, Toshiro; Haga, Yoshinori; Yamamoto, Etsuji; Amitsuka, Hiroshi; Tsutsumi, Yasumasa; Machida, Kazushige
2016-02-01
In order to gain insight into the superconducting (SC) gap of UBe13, we studied its quasiparticle excitations by means of heat-capacity measurements. Quite unexpectedly, we found the isotropic C(H) ∝ H behavior in low fields at low temperatures, implying the absence of nodal quasiparticle excitations. This result indicates that the SC gap in UBe13 is fully open over the Fermi surfaces. Furthermore, we observed a characteristic oscillation of heat capacity both in the SC and non-Fermi-liquid normal states above ∼2 T, and the angular variation of heat capacity possibly originates from anisotropic magnetic response of the heavy-electron state. Our result regarding the low-energy quasiparticle excitations in the SC and normal states will be a clue to understand the unusual nature of UBe13.
On rotational forces in the solar wind
NASA Technical Reports Server (NTRS)
Hollweg, J. V.; Isenberg, P. A.
1981-01-01
Solar rotational forces affecting the flow of minor ions in the solar wind are considered as corotating with the sun. Cold, noninteracting charged particles in the magnetic and gravitational fields of the sun rotate with the angular velocity of the sun, and calculations of lowest bulk order velocities show that differences in particle velocities decrease with increasing distance from the sun. A centrifugal potential in the corotating frame implies that ion motion is independent of protons, with velocities determined by the potential, which monotonically decreases without limit. The potential dominates the initial kinetic energy of the particles, and the equality of velocities within the potential is not due to interactions between particles as claimed by Mackenzie et al. (1979).
MODELING OF DIFFERENTIAL ROTATION IN RAPIDLY ROTATING SOLAR-TYPE STARS
Hotta, H.; Yokoyama, T.
2011-10-10
We investigate differential rotation in rapidly rotating solar-type stars by means of an axisymmetric mean field model that was previously applied to the Sun. This allows us to calculate the latitudinal entropy gradient with a reasonable physical basis. Our conclusions are as follows. (1) Differential rotation approaches the Taylor-Proudman state when stellar rotation is faster than solar rotation. (2) Entropy gradient generated by the attached subadiabatic layer beneath the convection zone becomes relatively small with a large stellar angular velocity. (3) Turbulent viscosity and turbulent angular momentum transport determine the spatial difference of angular velocity {Delta}{Omega}. (4) The results of our mean field model can explain observations of stellar differential rotation.
Rasmusson, A; Hahn, U; Larsen, J O; Gundersen, H J G; Jensen, E B Vedel; Nyengaard, J R
2013-05-01
This paper presents a new local volume estimator, the spatial rotator, which is based on measurements on a virtual 3D probe, using computer assisted microscopy. The basic design of the probe builds upon the rotator principle which requires only a few manual intersection markings, thus making the spatial rotator fast to use. Since a 3D probe is involved, it is expected that the spatial rotator will be more efficient than the the nucleator and the planar rotator, which are based on measurements in a single plane. An extensive simulation study shows that the spatial rotator may be more efficient than the traditional local volume estimators. Furthermore, the spatial rotator can be seen as a further development of the Cavalieri estimator, which does not require randomization of sectioning or viewing direction. The tissue may thus be sectioned in any arbitrary direction, making it easy to identify the specific tissue region under study. In order to use the spatial rotator in practice, however, it is necessary to be able to identify intersection points between cell boundaries and test rays in a series of parallel focal planes, also at the peripheral parts of the cell boundaries. In cases where over- and underprojection phenomena are not negligible, they should therefore be corrected for if the spatial rotator is to be applied. If such a correction is not possible, it is needed to avoid these phenomena by using microscopy with increased resolution in the focal plane. PMID:23488880
Ahn, Sang Hyeon; Kim, Jinna; Min, Hyun Jin; Chung, Hyo Jin; Hong, Jae Min; Lee, Jeung-Gweon; Kim, Chang-Hoon; Cho, Hyung-Ju
2015-01-01
Objectives The aim of this study was to identify correlations between sleep apnea severity and tongue volume or posterior airway space measured via three-dimensional reconstruction of volumetric computerized tomography (CT) images in patients with obstructive sleep apnea (OSA) for use in predicting OSA severity and in surgical treatment. We also assessed associations between tongue volume and Mallampati score. Methods Snoring/OSA male patients (n = 64) who underwent polysomnography, cephalometry, and CT scans were enrolled in this retrospective study. OSA was diagnosed when the apnea-hypopnea index (AHI) was greater than 5 (mild 5–14; moderate 15–29; severe>30). The patients were also categorized into the normal-mild group (n = 22) and the moderate-severe group (n = 42). Using volumetric CT images with the three-dimensional reconstruction technique, the volume of the tongue, posterior airway space volume, and intra-mandibular space were measured. The volumes, polysomnographic parameters, and physical examination findings were compared, and independent factors that are related to OSA were analysed. Results No associations between tongue volume or posterior airway space and the AHI were observed. However, multivariate linear analyses showed that tongue volume had significantly negative association with lowest O2 saturation (r = 0.365, p = 0.027). High BMI was related to an increase in tongue volume. Modified Mallampati scores showed borderline significant positive correlations with absolute tongue volume (r = 0.251, p = 0.046) and standardized tongue volume (absolute tongue volume / intramandibular area; r = 0.266, p = 0.034). Between the normal-mild and moderate-severe groups, absolute tongue volumes were not different, although the standardized tongue volume in the moderate-severe group was significantly higher. Conclusion Absolute tongue volume showed stronger associations with lowest O2 saturation during sleep than with the severity of AHI. We also found that