Gamow-Teller strength and lepton captures rates on 66-71Ni in stellar matter

NASA Astrophysics Data System (ADS)

Nabi, Jameel-Un; Majid, Muhammad

Charge-changing transitions play a significant role in stellar weak-decay processes. The fate of the massive stars is decided by these weak-decay rates including lepton (positron and electron) captures rates, which play a consequential role in the dynamics of core collapse. As per previous simulation results, weak interaction rates on nickel (Ni) isotopes have significant influence on the stellar core vis-à-vis controlling the lepton content of stellar matter throughout the silicon shell burning phases of high mass stars up to the presupernova stages. In this paper, we perform a microscopic calculation of Gamow-Teller (GT) charge-changing transitions, in the β-decay and electron capture (EC) directions, for neutron-rich Ni isotopes (66-71Ni). We further compute the associated weak-decay rates for these selected Ni isotopes in stellar environment. The computations are accomplished by employing the deformed proton-neutron quasiparticle random phase approximation (pn-QRPA) model. A recent study showed that the deformed pn-QRPA theory is well suited for the estimation of GT transitions. The astral weak-decay rates are determined over densities in the range of 10-1011g/cm3 and temperatures in the range of 0.01 × 109-30 × 109K. The calculated lepton capture rates are compared with the previous calculation of Pruet and Fuller (PF). The overall comparison demonstrates that, at low stellar densities and high temperatures, our EC rates are bigger by as much as two orders of magnitude. Our results show that, at higher temperatures, the lepton capture rates are the dominant mode for the stellar weak rates and the corresponding lepton emission rates may be neglected.

The Gamow-state description of the decay energy spectrum of neutron-unbound 25O

NASA Astrophysics Data System (ADS)

Id Betan, R. M.; de la Madrid, R.

2018-02-01

We show the feasibility of calculating the decay energy spectrum of neutron emitting nuclei within the Gamow-state description of resonances by obtaining the decay energy spectrum of 25O. We model this nucleus as a valence neutron interacting with an 24O inert core, and we obtain the resulting resonant energies, widths and decay energy spectra for the ground and first excited states. We also discuss the similarities and differences between the decay energy spectrum of a Gamow state and the Breit-Wigner distribution with energy-dependent width.

Study of Gamow-Teller strength and associated weak-rates on odd-A nuclei in stellar matter

NASA Astrophysics Data System (ADS)

Majid, Muhammad; Nabi, Jameel-Un; Riaz, Muhammad

In a recent study by Cole et al. [A. L. Cole et al., Phys. Rev. C 86 (2012) 015809], it was concluded that quasi-particle random phase approximation (QRPA) calculations show larger deviations and overestimate the total experimental Gamow-Teller (GT) strength. It was also concluded that QRPA calculated electron capture rates exhibit larger deviation than those derived from the measured GT strength distributions. The main purpose of this study is to probe the findings of the Cole et al. paper. This study gives useful information on the performance of QRPA-based nuclear models. As per simulation results, the capturing of electrons that occur on medium heavy isotopes have a significant role in decreasing the ratio of electron-to-baryon content of the stellar interior during the late stages of core evolution. We report the calculation of allowed charge-changing transitions strength for odd-A fp-shell nuclei (45Sc and 55Mn) by employing the deformed pn-QRPA approach. The computed GT transition strength is compared with previous theoretical calculations and measured data. For stellar applications, the corresponding electron capture rates are computed and compared with rates using previously calculated and measured GT values. Our finding shows that our calculated results are in decent accordance with measured data. At higher stellar temperature, our calculated electron capture rates are larger than those calculated by independent particle model (IPM) and shell model. It was further concluded that at low temperature and high density regions, the positron emission weak-rates from 45Sc and 55Mn may be neglected in simulation codes.

Gamow-Teller response in the configuration space of a density-functional-theory-rooted no-core configuration-interaction model

NASA Astrophysics Data System (ADS)

Konieczka, M.; Kortelainen, M.; Satuła, W.

2018-03-01

Background: The atomic nucleus is a unique laboratory in which to study fundamental aspects of the electroweak interaction. This includes a question concerning in medium renormalization of the axial-vector current, which still lacks satisfactory explanation. Study of spin-isospin or Gamow-Teller (GT) response may provide valuable information on both the quenching of the axial-vector coupling constant as well as on nuclear structure and nuclear astrophysics. Purpose: We have performed a seminal calculation of the GT response by using the no-core configuration-interaction approach rooted in multireference density functional theory (DFT-NCCI). The model treats properly isospin and rotational symmetries and can be applied to calculate both the nuclear spectra and transition rates in atomic nuclei, irrespectively of their mass and particle-number parity. Methods: The DFT-NCCI calculation proceeds as follows: First, one builds a configuration space by computing relevant, for a given physical problem, (multi)particle-(multi)hole Slater determinants. Next, one applies the isospin and angular-momentum projections and performs the isospin and K mixing in order to construct a model space composed of linearly dependent states of good angular momentum. Eventually, one mixes the projected states by solving the Hill-Wheeler-Griffin equation. Results: The method is applied to compute the GT strength distribution in selected N ≈Z nuclei including the p -shell 8Li and 8Be nuclei and the s d -shell well-deformed nucleus 24Mg. In order to demonstrate a flexibility of the approach we present also a calculation of the superallowed GT β decay in doubly-magic spherical 100Sn and the low-spin spectrum in 100In. Conclusions: It is demonstrated that the DFT-NCCI model is capable of capturing the GT response satisfactorily well by using a relatively small configuration space, exhausting simultaneously the GT sum rule. The model, due to its flexibility and broad range of applicability, may

High-resolution study of Gamow-Teller transitions via the 54Fe(3He,t)54Co reaction

NASA Astrophysics Data System (ADS)

Adachi, T.; Fujita, Y.; Bacher, A. D.; Berg, G. P. A.; Black, T.; de Frenne, D.; Foster, C. C.; Fujita, H.; Fujita, K.; Hatanaka, K.; Honma, M.; Jacobs, E.; Jänecke, J.; Kanzaki, K.; Katori, K.; Nakanishi, K.; Negret, A.; Otsuka, T.; Popescu, L.; Roberts, D. A.; Sakemi, Y.; Shimbara, Y.; Shimizu, Y.; Stephenson, E. J.; Tameshige, Y.; Tamii, A.; Uchida, M.; Ueno, H.; Yamanaka, T.; Yosoi, M.; Zell, K. O.

2012-02-01

The Gamow-Teller transition strengths, B(GT), in pf-shell nuclei are of interest in nuclear physics as well as in nuclear astrophysics. A high-resolution (3He,t) charge-exchange (CE) reaction was performed on the Tz=+1 nucleus 54Fe at 0∘ and at an intermediate incident energy of 140 MeV/nucleon for the study of precise GT transition strengths to the final Tz=0 nucleus 54Co. By applying dispersion matching techniques for a high-quality 3He beam at RCNP, an energy resolution of 21 keV and an angular resolution of 5 mr were realized. The bumplike structure of the GT resonance observed in low-resolution CE reactions at around the excitation energy (Ex) of 10 MeV was resolved in individual L = 0, GT states. Excitation strengths were obtained for these GT states. If the R2 value that is defined by the ratio between GT and Fermi unit cross sections is known, the B(GT) values can be determined from the excitation strengths. For the derivation of the R2 value, the “merged analysis” combining the GT strength distribution from the 54Fe(3He,t)54Co study and the half-life from a 54Ni β decay was used, where T=1 isospin symmetry for A=54 isobars was assumed. The GT strengths were compared with a shell-model calculation using the GXPF1 interaction. The final GT states can have the isospin values T = 0, 1, and 2. The isospin T of each GT state observed in the 8.3≤Ex≤12.0 MeV region of the 54Fe(3He,t)54Co spectrum was identified by comparing the excitation strength with that of corresponding M1 state observed in a 54Fe(p,p')54Fe experiment. The B(GT) values of the states identified to have T=2, in particular, are of importance for the calculation of the electron capture rates at the core-collapse stage of presupernovae. The B(GT) strengths were further compared with B(M1) strengths measured in the 54Fe(e,e')54Fe reaction. In the M1 excitation using an electromagnetic probe, isoscalar (IS) and isovector (IV) orbital type operators are active in addition to the IV spin

Isospin symmetry of Tz =±3/2→±1/2 Gamow-Teller transitions in A=41 nuclei

NASA Astrophysics Data System (ADS)

Fujita, Y.; Shimbara, Y.; Adachi, T.; Berg, G. P.; Brown, B. A.; Fujita, H.; Hatanaka, K.; Kamiya, J.; Nakanishi, K.; Sakemi, Y.; Sasaki, S.; Shimizu, Y.; Tameshige, Y.; Uchida, M.; Wakasa, T.; Yosoi, M.

2004-11-01

Under the assumption that isospin T is a good quantum number, isobaric analog states and various analogous transitions are expected in isobars with mass number A . The strengths of Tz =±3/2→±1/2 analogous Gamow-Teller (GT) transitions and analogous M1 transitions within the A=41 isobar quartet are compared in detail. The Tz =+3/2→+1/2 GT transitions from the Jπ = 3/2+ ground state of 41K leading to excited Jπ = 1/2+ , 3/2+ , and 5/2+ states in 41Ca were measured using the ( 3He ,t) charge-exchange reaction. With a high energy resolution of 35 keV , many fragmented states were observed, and the GT strength distribution was determined up to 10 MeV excitation energy ( Ex ) . The main part of the strength was concentrated in the Ex =4 6 MeV region. A shell-model calculation could reproduce the concentration, but not so well details of the strength distribution. The obtained distribution was further compared with two results of 41Ti β decay studying the analogous Tz =-3/2→-1/2 GT strengths. They reported contradicting distributions. One-to-one correspondences of analogous transitions and analog states were assigned up to Ex =6 MeV in the comparison with one of these 41Ti β -decay results. Combining the spectroscopic information of the analog states in 41Ca and 41Sc , the most probable Jπ values were deduced for each pair of analog states. It was found that 5/2+ states carry the main part of the observed GT strength, while much less GT strength was carried by 1/2+ and 3/2+ states. The gross features of the GT strength distributions for each J were similar for the isospin analogous Tz =±3/2→±1/2 transitions, but the details were somewhat different. From the difference of the distributions, isospin-asymmetry matrix elements of ≈8 keV were deduced. The Coulomb displacement energy, which is sensitive to the configuration of states, showed a sudden increase of about 50 keV at the excitation energy of 3.8 MeV . The strengths of several M1 transitions to the

Spin-isospin excitations from the ground-state of 64Ni

NASA Astrophysics Data System (ADS)

Popescu, L.; Adachi, T.; Bäumer, C.; Berg, G. P. A.; van den Berg, A. M.; von Brentano, P.; Frekers, D.; de Frenne, D.; Fujita, K.; Fujita, Y.; Grewe, E. W.; Haefner, P.; Hatanaka, K.; Hunyadi, M.; de Huu, M.; Jacobs, E.; Johansson, H.; Korff, A.; Negret, A.; Nakanishi, K.; von Neumann-Cosel, P.; Rakers, S.; Ryezayeva, N.; Sakemi, Y.; Shevchenko, A.; Shimbara, Y.; Shimizu, Y.; Simon, H.; Tameshige, Y.; Tamii, A.; Uchida, M.; Wörtche, H. J.; Yosoi, M.

2006-03-01

Spin-isospin (Gamow-Teller) excitations in 64Cu and 64Co have been studied using (3He,t) and (d,2He) charge-exchange reactions on 64Ni. As the isospin of the 64Ni ground-state is T0=4, states with T=3, 4 and 5 in 64Cu are excited via the (3He,t) reaction and states with T=5 in 64Co via (d,2He). If we assume that the nuclear interaction is charge symmetric, the T=5 states in 64Cu should appear at corresponding excitation energies (if corrected for the Coulomb displacement) and with similar strengths as the T=5 states in 64Co. As in the 64Cu spectrum the T=5 states are very weakly excited, only by combining the results of the two complementary experiments one can estimate the Gamow-Teller strength starting from 64Ni in a consistent way.

Spin-isospin excitations from the ground-state of 64Ni

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popescu, L.; Frenne, D. de; Jacobs, E.

2006-03-13

Spin-isospin (Gamow-Teller) excitations in 64Cu and 64Co have been studied using (3He,t) and (d,2He) charge-exchange reactions on 64Ni. As the isospin of the 64Ni ground-state is T0=4, states with T=3, 4 and 5 in 64Cu are excited via the (3He,t) reaction and states with T=5 in 64Co via (d,2He). If we assume that the nuclear interaction is charge symmetric, the T=5 states in 64Cu should appear at corresponding excitation energies (if corrected for the Coulomb displacement) and with similar strengths as the T=5 states in 64Co. As in the 64Cu spectrum the T=5 states are very weakly excited, only bymore » combining the results of the two complementary experiments one can estimate the Gamow-Teller strength starting from 64Ni in a consistent way.« less

Gamow-Teller Strength Distributions in {sup 48}Sc by the {sup 48}Ca(p,n) and {sup 48}Ti(n,p) Reactions and Two-Neutrino Double-beta Decay Nuclear Matrix Elements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yako, K.; Sasano, M.; Miki, K.

2009-07-03

The double-differential cross sections for the {sup 48}Ca(p,n) and {sup 48}Ti(n,p) reactions were measured at 300 MeV. A multipole decomposition technique was applied to the spectra to extract the Gamow-Teller (GT) components. The integrated GT strengths up to an excitation energy of 30 MeV in {sup 48}Sc are 15.3+-2.2 and 2.8+-0.3 in the (p,n) and (n,p) spectra, respectively. In the (n,p) spectra additional GT strengths were found above 8 MeV where shell models within the fp shell-model space predict almost no GT strengths, suggesting that the present shell-model description of the nuclear matrix element of the two-neutrino double-beta decay ismore » incomplete.« less

Measurements of the {sup 116}Cd(p,n) and {sup 116}Sn(n,p) reactions at 300 MeV for studying Gamow-Teller transition strengths in the intermediate nucleus of the {sup 116}Cd double-{beta} decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasano, M.; Kuboki, H.; Sekiguchi, K.

2009-11-09

The double differential cross sections for the {sup 116}Cd(p,n) and {sup 116}Sn(n,p) reactions at 300 MeV have been measured over a wide excitation-energy region including Gamow-Teller (GT) giant resonance (GTGR) for studying GT transition strengths in the intermediate nucleus of the {sup 116}Cd double-{beta} decay, namely {sup 116}In. A large amount of the strengths in the {beta}{sup +} direction has been newly found in the energy region up to 30 MeV, which may imply that the GT strengths in the GTGR region contribute to the nuclear matrix element of the two-neutrino double-{beta} decay.

George Gamow: Scientific Amateur and Polymath

NASA Astrophysics Data System (ADS)

Harper, Eamon

George Gamow (1904-1968) was among the first of the many brilliant scientists who forsook Europe for the United States in the early 1930s. Although most were fleeing the fascist imperium of Hitler and Mussolini, Gamow was one of a few who managed to escape the burgeoning despotism of Stalin in the Soviet Union. His early application of quantum mechanics to the atomic nucleus and his subsequent insight into the role played by the physics of the atom and its nucleus in stars, galaxies, and the universe identifies him as a scientist of unusual genius. Gamow displayed a boisterous, infectious - almost Rutherfordian - interest in all aspects of pure science. His interests were broad and his industry prodigious. His scientific output covered areas as diverse as nuclear physics, astrophysics, cosmology, biological genetics, and the fascinating question of the relationship of the large-scale structure and development of the universe to the properties of elementary particles and fields. He also was an immensely imaginative and prolific author of popular expositions on scientific subjects. One who is as well-known for his authorship of the Mr. Tompkins series of science popularizations as for his contributions to the development of the physical consequences of the big-bang theory of the expanding universe and the prediction of the cosmic background radiation must be unique in the scientific pantheon.

Dynamic Jahn-Teller effect in the parent insulating state of the molecular superconductor Cs₃C₆₀.

PubMed

Klupp, Gyöngyi; Matus, Péter; Kamarás, Katalin; Ganin, Alexey Y; McLennan, Alec; Rosseinsky, Matthew J; Takabayashi, Yasuhiro; McDonald, Martin T; Prassides, Kosmas

2012-06-19

The 'expanded fulleride' Cs(3)C(60) is an antiferromagnetic insulator in its normal state and becomes a molecular superconductor with T(c) as high as 38 K under pressure. There is mounting evidence that superconductivity is not of the conventional BCS type and electron-electron interactions are essential for its explanation. Here we present evidence for the dynamic Jahn-Teller effect as the source of the dramatic change in electronic structure occurring during the transition from the metallic to the localized state. We apply infrared spectroscopy, which can detect subtle changes in the shape of the C(60)3- ion due to the Jahn-Teller distortion. The temperature dependence of the spectra in the insulating phase can be explained by the gradual transformation from two temperature-dependent solid-state conformers to a single one, typical and unique for Jahn-Teller systems. These results unequivocally establish the relevance of the dynamic Jahn-Teller effect to overcoming Hund's rule and forming a low-spin state, leading to a magnetic Mott-Jahn-Teller insulator.

On the Time-Dependent Analysis of Gamow Decay

ERIC Educational Resources Information Center

Durr, Detlef; Grummt, Robert; Kolb, Martin

2011-01-01

Gamow's explanation of the exponential decay law uses complex "eigenvalues" and exponentially growing "eigenfunctions". This raises the question, how Gamow's description fits into the quantum mechanical description of nature, which is based on real eigenvalues and square integrable wavefunctions. Observing that the time evolution of any…

Dynamical Jahn-Teller effect of fullerene anions

NASA Astrophysics Data System (ADS)

Liu, Dan; Iwahara, Naoya; Chibotaru, Liviu F.

2018-03-01

The dynamical Jahn-Teller effect of C60n - anions (n =1 -5) is studied using the numerical diagonalization of the linear pn⊗8 d Jahn-Teller Hamiltonian with the currently established coupling parameters. It is found that in all anions the Jahn-Teller effect stabilizes the low-spin states, resulting in the violation of Hund's rule. The energy gain due to the Jahn-Teller dynamics is found to be comparable to the static Jahn-Teller stabilization. The Jahn-Teller dynamics influences the thermodynamic properties via strong variation of the density of vibronic states with energy. Thus the large vibronic entropy in the low-spin states enhances the effective spin gap of C603 - quenching the spin crossover. From the calculations of the effective spin gap as a function of the Hund's rule coupling, we found that the latter should amount 40 ±5 meV in order to cope with the violation of Hund's rule and to reproduce the large spin gap. With the obtained numerical solutions, the matrix elements of electronic operators for the low-lying vibronic levels and the vibronic reduction factors are calculated for all anions.

Gamow on Newton: Another Look at Centripetal Acceleration

ERIC Educational Resources Information Center

Corrao, Christian

2012-01-01

Presented here is an adaptation of George Gamow's derivation of the centripetal acceleration formula as it applies to Earth's orbiting Moon. The derivation appears in Gamows short but engaging book "Gravity", first published in 1962, and is essentially a distillation of Newton's work. While "TPT" contributors have offered several insightful…

Realistic Gamow shell model for resonance and continuum in atomic nuclei

NASA Astrophysics Data System (ADS)

Xu, F. R.; Sun, Z. H.; Wu, Q.; Hu, B. S.; Dai, S. J.

2018-02-01

The Gamow shell model can describe resonance and continuum for atomic nuclei. The model is established in the complex-moment (complex-k) plane of the Berggren coordinates in which bound, resonant and continuum states are treated on equal footing self-consistently. In the present work, the realistic nuclear force, CD Bonn, has been used. We have developed the full \\hat{Q}-box folded-diagram method to derive the realistic effective interaction in the model space which is nondegenerate and contains resonance and continuum channels. The CD-Bonn potential is renormalized using the V low-k method. With choosing 16O as the inert core, we have applied the Gamow shell model to oxygen isotopes.

On a Class of Hairy Square Barriers and Gamow Vectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fernandez-Garcia, N.

The second order Darboux-Gamow transformation is applied to deform square one dimensional barriers in non-relativistic quantum mechanics. The initial and the new 'hairy' potentials have the same transmission probabilities (for the appropriate parameters). In general, new Gamow vectors are constructed as Darboux deformations of the initial ones.

Teller, Edward (1908-)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

American physicist, born in Budapest, Hungary; at George Washington University collaborated with George Gamow in studying nuclear beta decay, and astrophysics. Worked on the atomic and hydrogen bombs....

Andrew Liehr and the structure of Jahn-Teller surfaces

NASA Astrophysics Data System (ADS)

Chibotaru, Liviu F.; Iwahara, Naoya

2017-05-01

The present article is an attempt to draw attention to a seminal work by Andrew Liehr “Topological aspects of conformational stability problem” [1, 2] issued more than half century ago. The importance of this work stems from two aspects of static Jahn-Teller and pseudo-Jahn-Teller problems fully developed by the author. First, the work of Liehr offers an almost complete overview of adiabatic potential energy surfaces for most known Jahn-Teller problems including linear, quadratic and higher-order vibronic couplings. Second, and most importantly, it identifies the factors defining the structure of Jahn-Teller surfaces. Among them, one should specially mention the minimax principle stating that the distorted Jahn-Teller systems tend to preserve the highest symmetry consistent with the loss of their orbital degeneracy. We believe that the present short reminiscence not only will introduce a key Jahn-Teller scientist to the young members of the community but also will serve as a vivid example of how a complete understanding of a complex problem, which the Jahn-Teller effect certainly was in the beginning of 1960s, can be achieved.

Structure and decays of nuclear three-body systems: The Gamow coupled-channel method in Jacobi coordinates

NASA Astrophysics Data System (ADS)

Wang, S. M.; Michel, N.; Nazarewicz, W.; Xu, F. R.

2017-10-01

Background: Weakly bound and unbound nuclear states appearing around particle thresholds are prototypical open quantum systems. Theories of such states must take into account configuration mixing effects in the presence of strong coupling to the particle continuum space. Purpose: To describe structure and decays of three-body systems, we developed a Gamow coupled-channel (GCC) approach in Jacobi coordinates by employing the complex-momentum formalism. We benchmarked the complex-energy Gamow shell model (GSM) against the new framework. Methods: The GCC formalism is expressed in Jacobi coordinates, so that the center-of-mass motion is automatically eliminated. To solve the coupled-channel equations, we use hyperspherical harmonics to describe the angular wave functions while the radial wave functions are expanded in the Berggren ensemble, which includes bound, scattering, and Gamow states. Results: We show that the GCC method is both accurate and robust. Its results for energies, decay widths, and nucleon-nucleon angular correlations are in good agreement with the GSM results. Conclusions: We have demonstrated that a three-body GSM formalism explicitly constructed in the cluster-orbital shell model coordinates provides results similar to those with a GCC framework expressed in Jacobi coordinates, provided that a large configuration space is employed. Our calculations for A =6 systems and 26O show that nucleon-nucleon angular correlations are sensitive to the valence-neutron interaction. The new GCC technique has many attractive features when applied to bound and unbound states of three-body systems: it is precise, is efficient, and can be extended by introducing a microscopic model of the core.

The vibrational Jahn-Teller effect in E⊗e systems

NASA Astrophysics Data System (ADS)

Thapaliya, Bishnu P.; Dawadi, Mahesh B.; Ziegler, Christopher; Perry, David S.

2015-10-01

The Jahn-Teller theorem is applied in the vibrational context where degenerate high-frequency vibrational states (E) are considered as adiabatic functions of low-frequency vibrational coordinates (e). For CH3CN and Cr(C6H6)(CO)3, the global minimum of the non-degenerate electronic potential energy surface occurs at the C3v geometry, but in CH3OH, the equilibrium geometry is far from the C3v reference geometry. In the former cases, the computed spontaneous Jahn-Teller distortion is exceptionally small. In methanol, the vibrational Jahn-Teller interaction results in the splitting of the degenerate E-type CH stretch into what have been traditionally assigned as the distinct ν2 and ν9 vibrational bands. The ab initio vibrational frequencies are fit precisely by a two-state high-order Jahn-Teller Hamiltonian (Viel and Eisfeld, 2004). The presence of vibrational conical intersections, including 7 for CH3OH, has implications for spectroscopy, for geometric phase, and for ultrafast localized non-adiabatic energy transfer.

Quantum shielding effects on the Gamow penetration factor for nuclear fusion reaction in quantum plasmas

NASA Astrophysics Data System (ADS)

Lee, Myoung-Jae; Jung, Young-Dae

2017-01-01

The quantum shielding effects on the nuclear fusion reaction process are investigated in quantum plasmas. The closed expression of the classical turning point for the Gamow penetration factor in quantum plasmas is obtained by the Lambert W-function. The closed expressions of the Gamow penetration factor and the cross section for the nuclear fusion reaction in quantum plasmas are obtained as functions of the plasmon energy and the relative kinetic energy by using the effective interaction potential with the WKB analysis. It is shown that the influence of quantum screening suppresses the Sommerfeld reaction factor. It is also shown that the Gamow penetration factor increases with an increase of the plasmon energy. It is also shown that the quantum shielding effect enhances the deuterium formation by the proton-proton reaction in quantum plasmas. In addition, it is found that the energy dependences on the reaction cross section and the Gamow penetration factor are more significant in high plasmon-energy domains.

Gamow-Teller Strength for the Mixed Ground State of ARGON-35 via the (proton, Neutron) Reaction.

NASA Astrophysics Data System (ADS)

Wagner, Anthony James

1988-12-01

Early asymmetry measurements of the mixed beta-decay of the ground state of ^{35}Ar to the ground state of ^{35}Cl showed an "anomalous" value of G_{rm V}. This anomalous value surprisingly would infer that unitary symmetry, believed to be spontaneously broken in nature, has been restored in this singular case. From the definition of rho^2, this "anomalous" value also infers a "anomalous" value for B(GT)/B(F). When the half-life data is used instead without the results of the asymmetry experiment, one obtains a different ("normal") value of B(GT)/B(F). The quantity rho^2 derived from the early asymmetry experiments is considered suspect. It has recently been shown that the (p,n) reaction at intermediate energies provides a strong interaction probe of the identical B(GT)/B(F) nuclear strength ratio that can be measured in beta-decay. The value of G_{rm A}/G _{rm V} has been determined very accurately from the beta -decay of the neutron. Thus, (p,n) can be used to determine via a totally independent measurement the value of B(GT)/B(F). The global proportionality constant E _{rm O} = 55 +/- 0.4 MeV is used to analyze the results of a 160 MeV Polarimeter experiment to distinguish between the normal and anomalous value. The results showed more spin-flip probability than was expected. A 120 MeV cross section experiment was required to check whether there was additional spin-flip probability due to a non-negligible DeltaL = 2 component. The results showed a negligible DeltaL = 2 component. The specific proportionality ({ sigma}_{rm GT} (Ground State) = {sigma} _{rm GT} (Excited State)) was then used to reanalyze the results of both experiments. The results showed a B(GT)/B(F) = 0.058 +/- 0.007. The specific proportionality gave a global proportionality constant of E_{rm O} = 32.2 +/- 1.9 MeV. The reason for this deviation in E_{rm O} is not understood.

The Phenalenyl Free Radical - a Jahn-Teller D3H PAH

NASA Astrophysics Data System (ADS)

O'Connor, G. D.; Troy, T. P.; Roberts, D. A.; Chalyavi, N.; Fückel, B.; Crossley, M. J.; Nauta, K.; Schmidt, T. W.; Stanton, J. F.

2012-06-01

After benzene and naphthalene, the smallest polycyclic aromatic hydrocarbon bearing six-membered rings is the threefold-symmetric phenalenyl radical. Despite the fact that it is so fundamental, its electronic spectroscopy has not been rigorously scrutinized, in spite of growing interest in graphene fragments for molecular electronic applications. Here we used complementary laser spectroscopic techniques to probe the jet-cooled phenalenyl radical in vacuo. Its spectrum reveals the interplay between four electronic states that exhibit Jahn-Teller and pseudo-Jahn-Teller (Herzberg-Teller) vibronic coupling. The coupling mechanism has been elucidated by the application of various ab initio quantum-chemical techniques.

Optimized unconventional superconductivity in a molecular Jahn-Teller metal

PubMed Central

Zadik, Ruth H.; Takabayashi, Yasuhiro; Klupp, Gyöngyi; Colman, Ross H.; Ganin, Alexey Y.; Potočnik, Anton; Jeglič, Peter; Arčon, Denis; Matus, Péter; Kamarás, Katalin; Kasahara, Yuichi; Iwasa, Yoshihiro; Fitch, Andrew N.; Ohishi, Yasuo; Garbarino, Gaston; Kato, Kenichi; Rosseinsky, Matthew J.; Prassides, Kosmas

2015-01-01

Understanding the relationship between the superconducting, the neighboring insulating, and the normal metallic state above Tc is a major challenge for all unconventional superconductors. The molecular A3C60 fulleride superconductors have a parent antiferromagnetic insulator in common with the atom-based cuprates, but here, the C603– electronic structure controls the geometry and spin state of the structural building unit via the on-molecule Jahn-Teller effect. We identify the Jahn-Teller metal as a fluctuating microscopically heterogeneous coexistence of both localized Jahn-Teller–active and itinerant electrons that connects the insulating and superconducting states of fullerides. The balance between these molecular and extended lattice features of the electrons at the Fermi level gives a dome-shaped variation of Tc with interfulleride separation, demonstrating molecular electronic structure control of superconductivity. PMID:26601168

Jahn-Teller Effect: Its History and Applicability

DOE R&D Accomplishments Database

Teller, E.

1981-08-31

The interactions between Teller, Renner, Jahn and Landau which led to the formulation of the Jahn-Teller effect are discussed. The applicability of Jahn-Teller type of theory to superconductivity and the explanation proposed by the use of Goldstone particles are assessed.

Effective axial-vector strength and β-decay systematics

NASA Astrophysics Data System (ADS)

Delion, D. S.; Suhonen, J.

2014-09-01

We use the weak axial-vector coupling strength g_{\\text{A}} as a key parameter to reproduce simultaneously the available data for both the Gamow-Teller \\beta^- and \\beta^+/\\text{EC} decay rates in nine triplets of isobars with mass numbers A=70,78,100,104,106,110,116,128,130 . We use the proton-neutron quasiparticle random-phase approximation (pnQRPA) with schematic dipole interaction containing particle-particle and particle-hole parts with mass-dependent strengths. Our analysis points to a strongly quenched effective value g_{\\text{A}}\\approx 0.3 , with a relative error of 28%. We then perform a systematic computation of 218 experimentally known \\beta^- and \\beta^+/\\text{EC} decays with quite a remarkable success. The presently extracted value of g_{\\text{A}} should be taken as an effective one, specific for a given nuclear theory framework. Present studies suggest that the effective g_{\\text{A}} is suitable for the description of decay transitions to 1^+ states at moderate excitation, below the Gamow-Teller giant resonance region.

Jahn-Teller distortion in the phosphorescent excited state of three-coordinate Au(I) phosphine complexes.

PubMed

Barakat, Khaldoon A; Cundari, Thomas R; Omary, Mohammad A

2003-11-26

DFT calculations were used to optimize the phosphorescent excited state of three-coordinate [Au(PR3)3]+ complexes. The results indicate that the complexes rearrange from their singlet ground-state trigonal planar geometry to a T-shape in the lowest triplet luminescent excited state. The optimized structure of the exciton contradicts the structure predicted based on the AuP bonding properties of the ground-state HOMO and LUMO. The rearrangement to T-shape is a Jahn-Teller distortion because an electron is taken from the degenerate e' (5dxy, 5dx2-y2) orbital upon photoexcitation of the ground-state D3h complex. The calculated UV absorption and visible emission energies are consistent with the experimental data and explain the large Stokes' shifts while such correlations are not possible in optimized models that constrained the exciton to the ground-state trigonal geometry.

Jahn-Teller effect versus Hund's rule coupling in C60N-

NASA Astrophysics Data System (ADS)

Wehrli, S.; Sigrist, M.

2007-09-01

We propose variational states for the ground state and the low-energy collective rotator excitations in negatively charged C60N- ions (N=1,…,5) . The approach includes the linear electron-phonon coupling and the Coulomb interaction on the same level. The electron-phonon coupling is treated within the effective mode approximation which yields the linear t1u⊗Hg Jahn-Teller problem whereas the Coulomb interaction gives rise to Hund’s rule coupling for N=2,3,4 . The Hamiltonian has accidental SO(3) symmetry which allows an elegant formulation in terms of angular momenta. Trial states are constructed from coherent states and using projection operators onto angular momentum subspaces which results in good variational states for the complete parameter range. The evaluation of the corresponding energies is to a large extent analytical. We use the approach for a detailed analysis of the competition between Jahn-Teller effect and Hund’s rule coupling, which determines the spin state for N=2,3,4 . We calculate the low-spin-high-spin gap for N=2,3,4 as a function of the Hund’s rule coupling constant J . We find that the experimentally measured gaps suggest a coupling constant in the range J=60-80meV . Using a finite value for J , we recalculate the ground state energies of the C60N- ions and find that the Jahn-Teller energy gain is partly counterbalanced by the Hund’s rule coupling. In particular, the ground state energies for N=2,3,4 are almost equal.

Experimental investigation of the Jahn-Teller effect in the ground and excited electronic states of the tropyl radical. Part II. Vibrational analysis of the A 2E"3-X 2E"2 electronic transition.

PubMed

Sioutis, Ilias; Stakhursky, Vadim L; Tarczay, György; Miller, Terry A

2008-02-28

Laser-induced fluorescence (LIF) and laser-excited dispersed fluorescence (LEDF) spectra of the cycloheptatrienyl (tropyl) radical C7H7 have been observed under supersonic jet-cooling conditions. Assignment of the LIF excitation spectrum yields detailed information about the A-state vibronic structure. The LEDF emission was collected by pumping different vibronic bands of the A 2E"3<--X 2E"2 electronic spectrum. Analysis of the LEDF spectra yields valuable information about the vibronic levels of the X 2E"2 state. The X- and A-state vibronic structures characterize the Jahn-Teller distortion of the respective potential energy surfaces. A thorough analysis reveals observable Jahn-Teller activity in three of the four e'3 modes for the X 2E"2 state and two of the three e'1 modes for the A 2E"3 state and provides values for their deperturbed vibrational frequencies as well as linear Jahn-Teller coupling constants. The molecular parameters characterizing the Jahn-Teller interaction in the X and A states of C7H7 are compared to theoretical results and to those previously obtained for C5H5 and C6H6+.

Edward Teller

Science.gov Websites

physics, astrophysics, and statistical mechanics. Lawrence Livermore [National Laboratory] physicist Mort towering figures of 20th-century physics. ... Although his early training was in chemical physics and spectroscopy, Teller has made substantial contributions to such diverse fields as nuclear physics, plasma

Partial restoration of isospin symmetry for neutrinoless double β decay in the deformed nuclear system of 150Nd

NASA Astrophysics Data System (ADS)

Fang, Dong-Liang; Faessler, Amand; Simkovic, Fedor

2015-10-01

In this work, we calculate the matrix elements for the 0 ν β β decay of 150Nd using the deformed quasiparticle random-phase approximation (p n -QRPA) method. We adopted the approach introduced by Rodin and Faessler [Phys. Rev. C 84, 014322 (2011), 10.1103/PhysRevC.84.014322] and Simkovic et al. [Phys. Rev. C 87, 045501 (2013), 10.1103/PhysRevC.87.045501] to restore the isospin symmetry by enforcing MF2 ν=0 . We found that with this restoration, the Fermi matrix elements are reduced in the strongly deformed 150Nd by about 15 to 20%, while the more important Gamow-Teller matrix elements remain the same. The results of an enlarged model space are also presented. This enlargement increases the total (Fermi plus Gamow-Teller) matrix elements by less than 10%.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bes, D. R.; Civitarese, O.

The experimental information on isospin-spin excitations around {sup 58}Ni is analyzed by using isoscalar and isovector pairing vibrations, Gamow-Teller (GT) modes, and their couplings. It is found that the proposed coupling scheme accounts for a sizable amount of the strength associated with isospin-spin excitations, which include transitions to both one- and two-phonon states. The calculations are performed within the framework of perturbation theory, accounting for the renormalization of the charge by the collective GT excitations.

Underlying theory of a model for the Renner-Teller effect in tetra-atomic molecules: X(2)Πu electronic state of C2H2(+).

PubMed

Perić, M; Jerosimić, S; Mitić, M; Milovanović, M; Ranković, R

2015-05-07

In the present study, we prove the plausibility of a simple model for the Renner-Teller effect in tetra-atomic molecules with linear equilibrium geometry by ab initio calculations of the electronic energy surfaces and non-adiabatic matrix elements for the X(2)Πu state of C2H2 (+). This phenomenon is considered as a combination of the usual Renner-Teller effect, appearing in triatomic species, and a kind of the Jahn-Teller effect, similar to the original one arising in highly symmetric molecules. Only four parameters (plus the spin-orbit constant, if the spin effects are taken into account), which can be extracted from ab initio calculations carried out at five appropriate (planar) molecular geometries, are sufficient for building up the Hamiltonian matrix whose diagonalization results in the complete low-energy (bending) vibronic spectrum. The main result of the present study is the proof that the diabatization scheme, hidden beneath the apparent simplicity of the model, can safely be carried out, at small-amplitude bending vibrations, without cumbersome computation of non-adiabatic matrix elements at large number of molecular geometries.

Rotational Parameters from Vibronic Eigenfunctions of Jahn-Teller Active Molecules

NASA Astrophysics Data System (ADS)

Garner, Scott M.; Miller, Terry A.

2017-06-01

The structure in rotational spectra of many free radical molecules is complicated by Jahn-Teller distortions. Understanding the magnitudes of these distortions is vital to determining the equilibrium geometric structure and details of potential energy surfaces predicted from electronic structure calculations. For example, in the recently studied {\\widetilde{A}^2E^{''} } state of the NO_3 radical, the magnitudes of distortions are yet to be well understood as results from experimental spectroscopic studies of its vibrational and rotational structure disagree with results from electronic structure calculations of the potential energy surface. By fitting either vibrationally resolved spectra or vibronic levels determined by a calculated potential energy surface, we obtain vibronic eigenfunctions for the system as linear combinations of basis functions from products of harmonic oscillators and the degenerate components of the electronic state. Using these vibronic eigenfunctions we are able to predict parameters in the rotational Hamiltonian such as the Watson Jahn-Teller distortion term, h_1, and compare with the results from the analysis of rotational experiments.

Griffiths' inequalities for Ashkin-Teller model

NASA Technical Reports Server (NTRS)

Lee, C. T.

1973-01-01

The two Griffiths' (1967) inequalities for the correlation functions of Ising ferromagnets with two-body interactions, and two other inequalities obtained by Kelly and Sherman (1968) and by Sherman (1969) are shown to hold not only for the Ashkin-Teller (1943) model but also for a generalized Ashkin-Teller model (Kihara et al., 1954) with many-body interactions involving arbitrary clusters of particles. A cluster of particles is understood to mean a collection of pairs of particles rather than a group of particles. The four generalized inequalities under consideration are presented in the form of theorems, and a new inequality is obtained.

Shape coexistence and β decay of 70Br within a beyond-mean-field approach

NASA Astrophysics Data System (ADS)

Petrovici, A.

2018-02-01

β -decay properties of the odd-odd N =Z 70Br nucleus are self-consistently explored within the beyond-mean-field complex excited vampir variational model using an effective interaction obtained from a nuclear matter G -matrix based on the charge-dependent Bonn CD potential and an adequate model space. Results on superallowed Fermi β decay of the ground state and Gamow-Teller decay of the 9+ isomer in 70Br correlated with the shape coexistence and mixing effects on the structure and electromagnetic properties of the populated states in the daughter nucleus 70Se are presented and compared with available data.

A Genuine Jahn-Teller System with Compressed Geometry and Quantum Effects Originating from Zero-Point Motion.

PubMed

Aramburu, José Antonio; García-Fernández, Pablo; García-Lastra, Juan María; Moreno, Miguel

2016-07-18

First-principle calculations together with analysis of the experimental data found for 3d(9) and 3d(7) ions in cubic oxides proved that the center found in irradiated CaO:Ni(2+) corresponds to Ni(+) under a static Jahn-Teller effect displaying a compressed equilibrium geometry. It was also shown that the anomalous positive g∥ shift (g∥ -g0 =0.065) measured at T=20 K obeys the superposition of the |3 z(2) -r(2) ⟩ and |x(2) -y(2) ⟩ states driven by quantum effects associated with the zero-point motion, a mechanism first put forward by O'Brien for static Jahn-Teller systems and later extended by Ham to the dynamic Jahn-Teller case. To our knowledge, this is the first genuine Jahn-Teller system (i.e. in which exact degeneracy exists at the high-symmetry configuration) exhibiting a compressed equilibrium geometry for which large quantum effects allow experimental observation of the effect predicted by O'Brien. Analysis of the calculated energy barriers for different Jahn-Teller systems allowed us to explain the origin of the compressed geometry observed for CaO:Ni(+) . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

β decay of Si 38 , 40 ( T z = + 5 , + 6 ) to low-lying core excited states in odd-odd P 38 , 40 isotopes

DOE PAGES

Tripathi, Vandana; Lubna, R. S.; Abromeit, B.; ...

2017-02-08

Low-lying excited states in P 38,40 have been identified in the β decay of T z=+5,+6, Si 38,40. Based on the allowed nature of the Gamow-Teller (GT) decay observed, these states are assigned spin and parity of 1 + and are core-excited 1p1h intruder states with a parity opposite to the ground state. The occurrence of intruder states at low energies highlights the importance of pairing and quadrupole correlation energies in lowering the intruder states despite the N=20 shell gap. Configuration interaction shell model calculations with the state-of-art SDPF-MU effective interaction were performed to understand the structure of these 1p1hmore » states in the even-A phosphorus isotopes. States in P 40 with N=25 were found to have very complex configurations involving all the fp orbitals leading to deformed states as seen in neutron-rich nuclei with N≈28. The calculated GT matrix elements for the β decay highlight the dominance of the decay of the core neutrons rather than the valence neutrons.« less

β decay of Si 38 , 40 ( T z = + 5 , + 6 ) to low-lying core excited states in odd-odd P 38 , 40 isotopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tripathi, Vandana; Lubna, R. S.; Abromeit, B.

Low-lying excited states in P 38,40 have been identified in the β decay of T z=+5,+6, Si 38,40. Based on the allowed nature of the Gamow-Teller (GT) decay observed, these states are assigned spin and parity of 1 + and are core-excited 1p1h intruder states with a parity opposite to the ground state. The occurrence of intruder states at low energies highlights the importance of pairing and quadrupole correlation energies in lowering the intruder states despite the N=20 shell gap. Configuration interaction shell model calculations with the state-of-art SDPF-MU effective interaction were performed to understand the structure of these 1p1hmore » states in the even-A phosphorus isotopes. States in P 40 with N=25 were found to have very complex configurations involving all the fp orbitals leading to deformed states as seen in neutron-rich nuclei with N≈28. The calculated GT matrix elements for the β decay highlight the dominance of the decay of the core neutrons rather than the valence neutrons.« less

Teller Award Acceptance Speech (LIRPP Vol. 12)

NASA Astrophysics Data System (ADS)

McCrory, Robert L.

2016-10-01

It is indeed an honor to receive an award named for such an accomplished and famous physicist who is present with us today, Dr. Edward Teller. In thinking over what to say on this occasion, I noted that the Teller Award was given for pioneering research in controlled fusion, in controlling fusion for the benefit of mankind. I think everyone in this audience certainly would agree that this lofty goal is truly one of the unconquered, grand challenges in applied physics...

Observation of the 2+ isomer in 52Co

NASA Astrophysics Data System (ADS)

Orrigo, S. E. A.; Rubio, B.; Gelletly, W.; Blank, B.; Fujita, Y.; Giovinazzo, J.; Agramunt, J.; Algora, A.; Ascher, P.; Bilgier, B.; Cáceres, L.; Cakirli, R. B.; de France, G.; Ganioǧlu, E.; Gerbaux, M.; Grévy, S.; Kamalou, O.; Kozer, H. C.; Kucuk, L.; Kurtukian-Nieto, T.; Molina, F.; Popescu, L.; Rogers, A. M.; Susoy, G.; Stodel, C.; Suzuki, T.; Tamii, A.; Thomas, J. C.

2016-10-01

We report the first observation of the 2+ isomer in 52Co, produced in the β decay of the 0+, 52Ni ground state. We have observed three γ rays at 849, 1910, and 5185 keV characterizing the β de-excitation of the isomer. We have measured a half-life of 102(6) ms for the isomeric state. The Fermi and Gamow-Teller transition strengths for the β decay of Com52 to 52Fe have been determined. We also add new information on the β decay of the 6+, 52Co ground state, for which we have measured a half-life of 112(3) ms.

Occupational Noise Exposure among Toll Tellers at Toll Plaza in Malaysia

NASA Astrophysics Data System (ADS)

Azmi, Sharifah Nadya Syed; Dawal, Siti Zawiah Md; Ya, Tuan Mohammad Yusoff Shah Tuan; Saidin, Hamidi

2010-10-01

Toll tellers working at toll plaza have potential of exposure to high noise from the vehicles especially for the peak level of sound emitted by the heavy vehicles. However, occupational exposures in this workplace have not been adequately characterized and identified. Occupational noise exposure among toll tellers at toll plaza was assessed using Sound Level Meter, Noise Dosimeter and through questionnaire survey. These data were combined to estimate the work shift exposure level and health impacts to the toll tellers by using statistical analysis. Noise Dosimeter microphone was located at the hearing zone of the toll teller which working inside the toll booth and full-period measurements were collected for each work shift. The measurements were taken at 20 toll booths from 6.00 am to 2.00 pm for 5 days. 71 respondents participated in the survey to identify the symptoms of noise induced hearing loss and other health related problems among toll tellers. Results of this study indicated that occupational noise exposure among toll tellers for Mean Continuous Equivalent Level, Leq was 79.2±1.4 dB(A), Mean Maximum Level, Lmax was 107.8±3.6 dB(A) and Mean Peak Level, Lpeak was 136.6±9.9 dB. The Peak Level reported statistically significantly at 140 dB, the level of TLV recommended by ACGIH. The research findings indicated that the primary risk exposure to toll tellers comes from noise that emitted from heavy vehicles. Most of the toll tellers show symptoms of noise induced hearing loss and annoyed by the sources of noise at the toll plaza.

12 CFR 205.16 - Disclosures at automated teller machines.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 12 Banks and Banking 2 2011-01-01 2011-01-01 false Disclosures at automated teller machines. 205.16 Section 205.16 Banks and Banking FEDERAL RESERVE SYSTEM BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM ELECTRONIC FUND TRANSFERS (REGULATION E) § 205.16 Disclosures at automated teller machines. (a...

Structure of the two-neutrino double-β decay matrix elements within perturbation theory

NASA Astrophysics Data System (ADS)

Štefánik, Dušan; Šimkovic, Fedor; Faessler, Amand

2015-06-01

The two-neutrino double-β Gamow-Teller and Fermi transitions are studied within an exactly solvable model, which allows a violation of both spin-isospin SU(4) and isospin SU(2) symmetries, and is expressed with generators of the SO(8) group. It is found that this model reproduces the main features of realistic calculation within the quasiparticle random-phase approximation with isospin symmetry restoration concerning the dependence of the two-neutrino double-β decay matrix elements on isovector and isoscalar particle-particle interactions. By using perturbation theory an explicit dependence of the two-neutrino double-β decay matrix elements on the like-nucleon pairing, particle-particle T =0 and T =1 , and particle-hole proton-neutron interactions is obtained. It is found that double-β decay matrix elements do not depend on the mean field part of Hamiltonian and that they are governed by a weak violation of both SU(2) and SU(4) symmetries by the particle-particle interaction of Hamiltonian. It is pointed out that there is a dominance of two-neutrino double-β decay transition through a single state of intermediate nucleus. The energy position of this state relative to energies of initial and final ground states is given by a combination of strengths of residual interactions. Further, energy-weighted Fermi and Gamow-Teller sum rules connecting Δ Z =2 nuclei are discussed. It is proposed that these sum rules can be used to study the residual interactions of the nuclear Hamiltonian, which are relevant for charge-changing nuclear transitions.

Occasional Addresses by Edward Teller at Conferences of Laser Interaction and Related Plasma Phenomena (LIRPP)

NASA Astrophysics Data System (ADS)

Hora, Heinrich; Miley, George H.

2016-10-01

The following sections are included: * Futurology of High Intensity Lasers (LIRPP Vol. 3A) * Lecture in Connection with the Edward Teller Medal Award (LIRPP Vol. 10) * Photo of the First Recipients of the Edward Teller Medal in 1991 * Photos from the Edward Teller Medal Celebration in 1997 * Photo with Participants of the LIRPP No. 12 Conference, 1995 * Photo with Edward Teller Medalists at IFSA01, Kyoto, 2001 * Keynote Address: The Edward Teller Lecture (LIRPP Vol. 11) * Keynote Address: Dr. Edward Teller (LIRPP Vol. 12) * Teller Award Presentation and Keynote Address (LIRPP Vol. 13) * Laudations of Awardees 1991-1995 (LIRPP Vol. 13) * Laudations of Awardees 1999-2003

Universal Teller Curriculum Guide.

ERIC Educational Resources Information Center

DuPage Area Vocational Education Authority, Addison, IL.

This curriculum guide has been designed to provide the teacher with a basis for planning a comprehensive program in the career field of universal teller, and to allow the teacher and learner maximum flexibility. The teaching or instruction, in both educational and financial institutions, can be accomplished through large formal groups, small…

Jahn-Teller crystals - new class of smart materials

NASA Astrophysics Data System (ADS)

Kaplan, M. D.; Zimmerman, G. O.

2017-05-01

Jahn-Teller crystals represent a promising class in the search for new smart materials. Jahn- Teller multiferroics are of a special interest. We show that the properties of these crystals are not only “of interest for future applications”, but are already used and protected by various patents. Special attention is paid to some new results on magnetic shape memory effects in dielectrics because the physics of the corresponding materials is not yet completely clarified.

Perturbatively deformed defects in Pöschl-Teller-driven scenarios for quantum mechanics

NASA Astrophysics Data System (ADS)

Bernardini, Alex E.; da Rocha, Roldão

2016-07-01

Pöschl-Teller-driven solutions for quantum mechanical fluctuations are triggered off by single scalar field theories obtained through a systematic perturbative procedure for generating deformed defects. The analytical properties concerning the quantum fluctuations in one-dimension, zero-mode states, first- and second-excited states, and energy density profiles are all obtained from deformed topological and non-topological structures supported by real scalar fields. Results are firstly derived from an integrated λϕ4 theory, with corresponding generalizations applied to starting λχ4 and sine-Gordon theories. By focusing our calculations on structures supported by the λϕ4 theory, the outcome of our study suggests an exact quantitative correspondence to Pöschl-Teller-driven systems. Embedded into the perturbative quantum mechanics framework, such a correspondence turns into a helpful tool for computing excited states and continuous mode solutions, as well as their associated energy spectrum, for quantum fluctuations of perturbatively deformed structures. Perturbative deformations create distinct physical scenarios in the context of exactly solvable quantum systems and may also work as an analytical support for describing novel braneworld universes embedded into a 5-dimensional gravity bulk.

Surface Meteorology at Teller Site Stations, Seward Peninsula, Alaska, Ongoing from 2016

DOE Data Explorer

Bob Busey; Bob Bolton; Cathy Wilson; Lily Cohen

2017-12-05

Meteorological data are currently being collected at two locations at the Teller Site, Seward Peninsula. Teller Creek Station near TL_BSV (TELLER BOTTOM METEOROLOGICAL STATION) Station is located in the lower watershed in a tussock / willow transition zone and co-located with continuous snow depth measurements and subsurface measurements. Teller Creek Station near TL_IS_5 (TELLER TOP METEOROLOGICAL STATION) Station is located in the upper watershed and co-located with continuous snow depth measurements and subsurface measurements. Two types of data products are provided for these stations: First, meteorological and site characterization data grouped by sensor/measurement type (e.g., radiation or soil pit temperature and moisture). These are *.csv files. Second, a Data Visualization tool is provided for quick visualization of measurements over time at a station. Download the *_Visualizer.zip file, extract, and click on the 'index.html' file. Data values are the same in both products.

The ÖX˜ absorption of vinoxy radical revisited: Normal and Herzberg-Teller bands observed via cavity ringdown spectroscopy

NASA Astrophysics Data System (ADS)

Thomas, Phillip S.; Chhantyal-Pun, Rabi; Kline, Neal D.; Miller, Terry A.

2010-03-01

The ÖX˜ electronic absorption spectrum of vinoxy radical has been investigated using room temperature cavity ringdown spectroscopy. Analysis of the observed bands on the basis of computed vibrational frequencies and rotational envelopes reveals that two distinct types of features are present with comparable intensities. The first type corresponds to "normal" allowed electronic transitions to the origin and symmetric vibrations in the à state. The second type is interpreted in terms of excitations to asymmetric à state vibrations, which are only vibronically allowed by Herzberg-Teller coupling to the B˜ state. Results of electronic structure calculations indicate that the magnitude of the Herzberg-Teller coupling is appropriate to produce vibronically induced transitions with intensities comparable to those of the normal bands.

Influence of the Renner-Teller Coupling in CO+H Collision Dynamics

NASA Astrophysics Data System (ADS)

Ndengue, Steve Alexandre; Dawes, Richard

2017-06-01

Carbon monoxide is after molecular hydrogen the second most abundant molecule in the universe and an important molecule for processes occurring in the atmosphere, hydrocarbon combustion and the interstellar medium. The rate coefficients of CO in collision with dominant species like H, H_2, He, etc are necessary to understand the CO emission spectrum or to model combustion chemistry processes. The inelastic scattering of CO with H has been intensively studied theoretically in the past decades,^1 mostly using the so-called WKS PES^6 developed by Werner et al. or recently a modified version by Song et al.^2 Though the spectroscopic agreement of the WKS surface with experiment is quite good, so far the studies of scattering dynamics have neglected coupling to an electronic excited state. We present new results on a set of HCO surfaces of the ground and the excited Renner-Teller coupled electronic states^3 with the principal objective of studying the influence of the Renner-Teller coupling on the inelastic scattering of CO+H. Our calculations done using the MCTDH^4 algorithm in the 0-2 eV energy range allow evaluation of the contribution of the Renner-Teller coupling on the rovibrationally inelastic scattering and discuss the relevance and reliability of the calculations. References:} 1. N. Balakrishnan, M. Yan and A. Dalgarno, Astrophys. J. 568, 443 (2002); B.C. Shepler et al, Astron. & Astroph. 475, L15 (2007); L. Song et al, J. Chem. Phys. 142, 204303 (2015); K.M. Walker et al, Astroph. J. 811, 27 (2015). 2. L. Song et al, Astrophys. J. 813, 96 (2015). 3. H.-M. Keller et al, J. Chem. Phys. 105, 4983 (1996). 4. S. Ndengue, R. Dawes and H. Guo, J. Chem. Phys. 144, 244301 (2016). 5. M.H. Beck et al., Phys. Rep. 324, 1 (2000).

Formal verification of automated teller machine systems using SPIN

NASA Astrophysics Data System (ADS)

Iqbal, Ikhwan Mohammad; Adzkiya, Dieky; Mukhlash, Imam

2017-08-01

Formal verification is a technique for ensuring the correctness of systems. This work focuses on verifying a model of the Automated Teller Machine (ATM) system against some specifications. We construct the model as a state transition diagram that is suitable for verification. The specifications are expressed as Linear Temporal Logic (LTL) formulas. We use Simple Promela Interpreter (SPIN) model checker to check whether the model satisfies the formula. This model checker accepts models written in Process Meta Language (PROMELA), and its specifications are specified in LTL formulas.

Multimode Jahn-Teller effect in bulk systems: A case of the N V 0 center in diamond

DOE PAGES

Zhang, Jianhua; Wang, Cai -Zhuang; Zhu, Zizhong; ...

2018-04-15

Here, the multimode Jahn-Teller (JT) effect in a bulk system of a neutral nitrogen-vacancy (NV 0) center in diamond is investigated via first-principles density-functional-theory calculations and the intrinsic distortion path (IDP) method. The adiabatic potential energy surface of the electronic ground state of the NV 0 center is calculated based on the local spin-density approximation. Our calculations confirm the presence of the dynamic Jahn-Teller effect in the ground 2E state of the NV 0 center. Within the harmonic approximation, the IDP method provides the reactive path of JT distortion from unstable high-symmetry geometry to stable low-symmetry energy minimum geometry, andmore » it describes the active normal modes participating in the distortion. We find that there is more than one vibrational mode contributing to the distortion, and their contributions change along the IDP. Several vibrational modes with large contributions to JT distortion, especially those modes close to 44 meV, are clearly observed as the phonon sideband in photoluminescence spectra in a series of experiments, indicating that the dynamic Jahn-Teller effect plays an important role in the optical transition of the NV 0 center.« less

Multimode Jahn-Teller effect in bulk systems: A case of the N V0 center in diamond

NASA Astrophysics Data System (ADS)

Zhang, Jianhua; Wang, Cai-Zhuang; Zhu, Zizhong; Liu, Qing Huo; Ho, Kai-Ming

2018-04-01

The multimode Jahn-Teller (JT) effect in a bulk system of a neutral nitrogen-vacancy (N V0 ) center in diamond is investigated via first-principles density-functional-theory calculations and the intrinsic distortion path (IDP) method. The adiabatic potential energy surface of the electronic ground state of the N V0 center is calculated based on the local spin-density approximation. Our calculations confirm the presence of the dynamic Jahn-Teller effect in the ground 2E state of the N V0 center. Within the harmonic approximation, the IDP method provides the reactive path of JT distortion from unstable high-symmetry geometry to stable low-symmetry energy minimum geometry, and it describes the active normal modes participating in the distortion. We find that there is more than one vibrational mode contributing to the distortion, and their contributions change along the IDP. Several vibrational modes with large contributions to JT distortion, especially those modes close to 44 meV, are clearly observed as the phonon sideband in photoluminescence spectra in a series of experiments, indicating that the dynamic Jahn-Teller effect plays an important role in the optical transition of the N V0 center.

Multimode Jahn-Teller effect in bulk systems: A case of the N V 0 center in diamond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Jianhua; Wang, Cai -Zhuang; Zhu, Zizhong

Here, the multimode Jahn-Teller (JT) effect in a bulk system of a neutral nitrogen-vacancy (NV 0) center in diamond is investigated via first-principles density-functional-theory calculations and the intrinsic distortion path (IDP) method. The adiabatic potential energy surface of the electronic ground state of the NV 0 center is calculated based on the local spin-density approximation. Our calculations confirm the presence of the dynamic Jahn-Teller effect in the ground 2E state of the NV 0 center. Within the harmonic approximation, the IDP method provides the reactive path of JT distortion from unstable high-symmetry geometry to stable low-symmetry energy minimum geometry, andmore » it describes the active normal modes participating in the distortion. We find that there is more than one vibrational mode contributing to the distortion, and their contributions change along the IDP. Several vibrational modes with large contributions to JT distortion, especially those modes close to 44 meV, are clearly observed as the phonon sideband in photoluminescence spectra in a series of experiments, indicating that the dynamic Jahn-Teller effect plays an important role in the optical transition of the NV 0 center.« less

PREFACE: XXIst International Symposium on the Jahn-Teller Effect 2012

NASA Astrophysics Data System (ADS)

Koizumi, Hiroyasu

2013-04-01

is obtained. A related problem also arises when dealing with the so-called adiabatic-diabatic transformation (ADT) that removes coupling terms between different Born-Oppenheimer electronic states. It is known that an exact ADT does not exist in general, however, digital computers do this impossible task erroneously if we just plug in numbers. The results obtained may be good in practice; however, we need to be aware that such calculations may miss some important details. I asked Professor Mead to write a note on this matter since there is still confusion in the treatment of the ADT. The proper handling on the ADT may be a topic in the next Jahn-Teller symposium. Although more than a quarter of a century has passed since its discovery, the mechanism of cuprate superconductivity is still actively discussed. In the cuprate, the multi-valuedness problem arises when the conduction electrons create spin-vortices and the twisting of the spin basis occurs. Since a number of experiments and theories indicate the presence of spin-vortices in the cuprate, a proper handling of the multi-valuedness arising from the spin-degree-of-freedom will be important. It has been argued that such multi-valuedness induces a vector potential that generates the persistent current. As the papers in this proceedings indicate, the Jahn-Teller effects are ubiquitous in physics and chemistry. The ideas and methodologies developed in this community have very wide applicability. I believe that this community will continue to contribute to the advancement of science in a fundamental way. Hiroyasu Koizumi Tsukuba, February 2013 Conference photograph

First order phase transitions resulted from collective Jahn-Teller effect

NASA Astrophysics Data System (ADS)

Rosenfeld, E. V.

2018-01-01

Generally, in case of the collective Jahn-Teller effect, a high-symmetry structure of a matrix in which quantum systems with degenerate ground state are inserted becomes distorted. This usually smooth transition can become abrupt only if the matrix by itself is a trigger and JTE merely activates its switching. It is shown in this paper that proper insertion into matrix of quantum systems with the singlet ground state and degenerate excited state leads to the formation of a new metastable state of the whole system and a stepwise appearance of JTE. Using nanotechnology, a matrix of any nature can be transformed into trigger in this way if one manages to synthesize and insert into it proper quantity of quantum JT-active centers with appropriate energy spectrum.

Generalized Born-Oppenheimer treatment of Jahn-Teller systems in Hilbert spaces of arbitrary dimension: theory and application to a three-state model potential.

PubMed

Varandas, A J C; Sarkar, B

2011-05-14

Generalized Born-Oppenheimer equations including the geometrical phase effect are derived for three- and four-fold electronic manifolds in Jahn-Teller systems near the degeneracy seam. The method is readily extendable to N-fold systems of arbitrary dimension. An application is reported for a model threefold system, and the results are compared with Born-Oppenheimer (geometrical phase ignored), extended Born-Oppenheimer, and coupled three-state calculations. The theory shows unprecedented simplicity while depicting all features of more elaborated ones.

Vibrational and Nonadiabatic Coherence in 2D Electronic Spectroscopy, the Jahn-Teller Effect, and Energy Transfer

NASA Astrophysics Data System (ADS)

Jonas, David M.

2018-04-01

Femtosecond two-dimensional (2D) Fourier transform spectroscopy generates and probes several types of coherence that characterize the couplings between vibrational and electronic motions. These couplings have been studied in molecules with Jahn-Teller conical intersections, pseudo-Jahn-Teller funnels, dimers, molecular aggregates, photosynthetic light harvesting complexes, and photosynthetic reaction centers. All have closely related Hamiltonians and at least two types of vibrations, including one that is decoupled from the electronic dynamics and one that is nonadiabatically coupled. Polarized pulse sequences can often be used to distinguish these types of vibrations. Electronic coherences are rapidly obscured by inhomogeneous dephasing. The longest-lived coherences in these systems arise from delocalized vibrations on the ground electronic state that are enhanced by a nonadiabatic Raman excitation process. These characterize the initial excited-state dynamics. 2D oscillation maps are beginning to isolate the medium lifetime vibronic coherences that report on subsequent stages of the excited-state dynamics.

Energy-weighted sum rules connecting ΔZ = 2 nuclei within the SO(8) model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Štefánik, Dušan; Šimkovic, Fedor; Faessler, Amand

2013-12-30

Energy-weighted sum rules associated with ΔZ = 2 nuclei are obtained for the Fermi and the Gamow-Teller operators within the SO(8) model. It is found that there is a dominance of contribution of a single state of the intermediate nucleus to the sum rule. The results confirm founding obtained within the SO(5) model that the energy-weighted sum rules of ΔZ = 2 nuclei are governed by the residual interactions of nuclear Hamiltonian. A short discussion concerning some aspects of energy weighted sum rules in the case of realistic nuclei is included.

Precision experiments on mirror transitions at Notre Dame

NASA Astrophysics Data System (ADS)

Brodeur, Maxime; TwinSol Collaboration

2016-09-01

Thanks to extensive experimental efforts that led to a precise determination of important experimental quantities of superallowed pure Fermi transitions, we now have a very precise value for Vud that leads to a stringent test of the CKM matrix unitarity. Despite this achievement, measurements in other systems remain relevant as conflicting results could uncover unknown systematic effects or even new physics. One such system is the superallowed mixed transition, which can help refine theoretical corrections used for pure Fermi transitions and improve the accuracy of Vud. However, as a corrected Ft-value determination from these systems requires the more challenging determination of the Fermi Gamow-Teller mixing ratio, only five transitions, spreading from 19Ne to 37Ar, are currently fully characterized. To rectify the situation, an experimental program on precision experiment of mirror transitions that includes precision half-life measurements, and in the future, the determination of the Fermi Gamow-Teller mixing ratio, has started at the University of Notre Dame. This work is supported in part by the National Science Foundation.

Nonequilibrium phase transitions in isotropic Ashkin-Teller model

NASA Astrophysics Data System (ADS)

Akıncı, Ümit

2017-03-01

Dynamic behavior of an isotropic Ashkin-Teller model in the presence of a periodically oscillating magnetic field has been analyzed by means of the mean field approximation. The dynamic equation of motion has been constructed with the help of a Glauber type stochastic process and solved for a square lattice. After defining the possible dynamical phases of the system, phase diagrams have been given and the behavior of the hysteresis loops has been investigated in detail. The hysteresis loop for specific order parameter of isotropic Ashkin-Teller model has been defined and characteristics of this loop in different dynamical phases have been given.

Ashkin-Teller criticality and weak first-order behavior of the phase transition to a fourfold degenerate state in two-dimensional frustrated Ising antiferromagnets

NASA Astrophysics Data System (ADS)

Liu, R. M.; Zhuo, W. Z.; Chen, J.; Qin, M. H.; Zeng, M.; Lu, X. B.; Gao, X. S.; Liu, J.-M.

2017-07-01

We study the thermal phase transition of the fourfold degenerate phases (the plaquette and single-stripe states) in the two-dimensional frustrated Ising model on the Shastry-Sutherland lattice using Monte Carlo simulations. The critical Ashkin-Teller-like behavior is identified both in the plaquette phase region and the single-stripe phase region. The four-state Potts critical end points differentiating the continuous transitions from the first-order ones are estimated based on finite-size-scaling analyses. Furthermore, a similar behavior of the transition to the fourfold single-stripe phase is also observed in the anisotropic triangular Ising model. Thus, this work clearly demonstrates that the transitions to the fourfold degenerate states of two-dimensional Ising antiferromagnets exhibit similar transition behavior.

Gamow-Teller Strength Distributions for pf-shell Nuclei and its Implications in Astrophysics

NASA Astrophysics Data System (ADS)

Rahman, M.-U.; Nabi, J.-U.

2009-08-01

The {pf}-shell nuclei are present in abundance in the pre-supernova and supernova phases and these nuclei are considered to play an important role in the dynamics of core collapse supernovae. The B(GT) values are calculated for the {pf}-shell nuclei 55Co and 57Zn using the pn-QRPA theory. The calculated B(GT) strengths have differences with earlier reported shell model calculations, however, the results are in good agreement with the experimental data. These B(GT) strengths are used in the calculations of weak decay rates which play a decisive role in the core-collapse supernovae dynamics and nucleosynthesis. Unlike previous calculations the so-called Brink's hypothesis is not assumed in the present calculation which leads to a more realistic estimate of weak decay rates. The electron capture rates are calculated over wide grid of temperature ({0.01} × 109 - 30 × 109 K) and density (10-1011 g-cm-3). Our rates are enhanced compared to the reported shell model rates. This enhancement is attributed partly to the liberty of selecting a huge model space, allowing consideration of many more excited states in the present electron capture rates calculations.

Beta-decay strength and isospin mixing studies in the sd and fp-shells

NASA Astrophysics Data System (ADS)

Jokinen, A.; ńystö, J.; Dendooven, P.; Honkanen, A.; Lipas, P.; Peräjärvi, K.; Oinonen, M.; Siiskonen, T.

1998-12-01

We have studied beta decays of MT<0 nuclei in sd and fp shells. The decay of 41Ti shows a large, 10(8) %, isospin mixing of IAS and the Gamow-Teller strength is observed to be quenched by a factor of q2=0.64. These results can be reproduced qualitatively in our shell model calculations. We have observed for the first time proton and gamma decay of the isobaric analogue state in 23Mg. Our results on the isospin mixing of the isobaric analogue state agrees well with the shell model calculations. The obtained proton branch of the IAS is used to extract the transition strength for the reaction 22Na(p,γ)23Mg.

On the important role of the anti-Jahn-Teller effect in underdoped cuprate superconductors

NASA Astrophysics Data System (ADS)

Kamimura, Hiroshi; Matsuno, Shunichi; Mizokawa, Takashi; Sasaoka, Kenji; Shiraishi, Kenji; Ushio, Hideki

2013-04-01

In this paper it is shown that the "anti-Jahn-Teller effect" plays an essential role in giving rise to a small Fermi surface of Fermi pockets above Tc and d-wave superconductivity below Tc in underdoped cuprates. In the first part of the present paper, we review the latest developments of the model proposed by Kamimura and Suwa, which bears important characteristics born from the interplay of Jahn-Teller Physics and Mott Physics. It is shown that the feature of Fermi surfaces in underdoped LSCO is the Fermi pockets in the nodal region constructed by doped holes under the coexistence of a metallic state and of the local antiferromagnetic order. In the antinodal region in the momentum space, there are no Fermi surfaces. Then it is discussed that the phonon-involved mechanism based on the Kamimura-Suwa model leads to the d-wave superconductivity. In particular, it is shown that the origin of strong electron-phonon interactions in cuprates is due to the anti-Jahn-Teller effect. In the second part a recent theoretical result on the energy distribution curves (EDCs) of angle-resolved photoemission spectroscopy (ARPES) below Tc is discussed. It is shown that the feature of ARPES profiles of underdoped cuprates consists of a coherent peak in the nodal region and the real transitions of photoexcited electrons from occupied states below the Fermi level to a free-electron state above the vacuum level in the antinodal region, where the latter transitions form a broad hump. From this feature, the origin of the two distinct gaps observed by ARPES is elucidated without introducing the concept of the pseudogap. Finally, a remark is made on the phase diagram of underdoped cuprates.

Jahn-Teller effects in transition-metal compounds with small charge-transfer energy

NASA Astrophysics Data System (ADS)

Mizokawa, Takashi

2013-04-01

We have studied Jahn-Teller effects in Cs2Au2Br6, ACu3Co4O12(A=Ca or Y), and IrTe2 in which the ligand p-to-transition-metal d charge-transfer energy is small or negative. The Au+/Au3+ charge disproportionation of Cs2Au2Br6 manifests in Au 4f photoemission spectra. In Cs2Au2Br6 with negative Δ and intermediate U, the charge disproportionation can be described using effective d orbitals constructed from the Au 5d and Br 4p orbitals and is stabilized by the Jahn-Teller distortion of the Au3+ site with low-spin d8 configuration. In ACu3Co4O12, Δs for Cu3+ and Co4+ are negative and Us are very large. The Zhang-Rice picture is valid to describe the electronic state, and the valence change from Cu2+/Co4+ to Cu3+/Co3+ can be viewed as the O 2p hole transfer from Co to Cu or d9 + d6L → d9L + d6. In IrTe2, both Δ and U are small and the Ir 5d and Te 5p electrons are itinerant to form the multi-band Fermi surfaces. The ideas of band Jahn-Teller transition and Peierls transition are useful to describe the structural instabilities.

Quantifying the effects of higher order coupling terms on fits using a second order Jahn-Teller Hamiltonian

NASA Astrophysics Data System (ADS)

Tran, Henry K.; Stanton, John F.; Miller, Terry A.

2018-01-01

The limitations associated with the common practice of fitting a quadratic Hamiltonian to vibronic levels of a Jahn-Teller system have been explored quantitatively. Satisfactory results for the prototypical X∼2E‧ state of Li3 are obtained from fits to both experimental spectral data and to an "artificial" spectrum calculated by a quartic Hamiltonian which accurately reproduces the adiabatic potential obtained from state-of-the-art quantum chemistry calculations. However the values of the Jahn-Teller parameters, stabilization energy, and pseudo-rotation barrier obtained from the quadratic fit differ markedly from those associated with the ab initio potential. Nonetheless the RMS deviations of the fits are not strikingly different. Guidelines are suggested for comparing parameters obtained from fits to experiment to those obtained by direct calculation, but a principal conclusion of this work is that such comparisons must be done with a high degree of caution.

12 CFR 328.4 - Prohibition against receiving deposits at same teller station or window as noninsured institution.

Code of Federal Regulations, 2010 CFR

2010-01-01

... teller station or window as noninsured institution. 328.4 Section 328.4 Banks and Banking FEDERAL DEPOSIT... Prohibition against receiving deposits at same teller station or window as noninsured institution. (a) Prohibition. An insured depository institution may not receive deposits at any teller station or window where...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richter, W. A.; Mkhize, S.; Brown, B. Alex

The new Hamiltonians USDA and USDB for the sd shell are used to calculate M1 and E2 moments and transition matrix elements, Gamow-Teller {beta}-decay matrix elements, and spectroscopic factors for sd-shell nuclei from A=17 to A=39. The results are compared with those obtained with the older USD Hamiltonian and with experiment to explore the interaction sensitivity of these observables.

Cooperative Jahn-Teller phase transition of icosahedral molecular units

NASA Astrophysics Data System (ADS)

Nasrollahi, Seyed H.; Vvedensky, Dimitri D.

2017-02-01

Non-linear molecules undergo distortions when the orbital degeneracy of the highest occupied level is lifted by the Jahn-Teller effect. If such molecules or clusters of atoms are coupled to one another, the system may experience a cooperative Jahn-Teller effect (CJTE). In this paper, we describe a model of how the CJTE leads to the crystallization of the disordered phase. The model Hamiltonian is based on a normal mode decomposition of the clusters in order to maintain the symmetry labels. We take account of the electron-strain and the electron-phonon couplings and, by displacing the coordinates of the oscillators, obtain a term that explicitly couples the Jahn-Teller centers, enabling us to perform a mean-field analysis. The calculation of the free energy then becomes straightforward, and obtaining phase diagrams in various regimes follows from the minimization of this free energy. The results show that the character of the phase transition may change from strong to weak first order and even to second-order, depending on the coupling to the vibrational modes. Taken together, these results may serve as a paradigm for crystallization near the transition temperature, where the atoms tend to form clusters of icosahedral symmetry.

Absence of Jahn-Teller transition in the hexagonal Ba 3CuSb 2O 9 single crystal

DOE PAGES

Katayama, Naoyuki; Kimura, Kenta; Han, Yibo; ...

2015-07-13

With decreasing temperature, liquids generally freeze into a solid state, losing entropy in the process. However, exceptions to this trend exist, such as quantum liquids, which may remain unfrozen down to absolute zero owing to strong quantum entanglement effects that stabilize a disordered state with zero entropy. Examples of such liquids include Bose-Einstein condensation of cold atoms, superconductivity, quantum Hall state of electron systems, and quantum spin liquid state in the frustrated magnets. Furthermore, recent studies have clarified the possibility of another exotic quantum liquid state based on the spin-orbital entanglement in FeSc2S4. To confirm this exotic ground state, experimentsmore » based on single-crystalline samples are essential. However, no such single-crystal study has been reported to date. Here, we report, to our knowledge, the first single-crystal study on the spin-orbital liquid candidate, 6H-Ba3CuSb2O9, and we have confirmed the absence of an orbital frozen state. In strongly correlated electron systems, orbital ordering usually appears at high temperatures in a process accompanied by a lattice deformation, called a static Jahn-Teller distortion. By combining synchrotron X-ray diffraction, electron spin resonance, Raman spectroscopy, and ultrasound measurements, we find that the static Jahn-Teller distortion is absent in the present material, which indicates that orbital ordering is suppressed down to the lowest temperatures measured. Lastly, we discuss how such an unusual feature is realized with the help of spin degree of freedom, leading to a spin-orbital entangled quantum liquid state.« less

The complete set of spin observables for the (13)C(polarized proton, polarized neutron)(13)N and (15)N(polarized proton, polarized neutron)(15)O reactions

NASA Astrophysics Data System (ADS)

Du, Qun Qun

1998-12-01

The 13C(p,n)13N and 15N(p,n)15O reactions have been a puzzle for more than ten years. The ground state transitions are Jπ=1/2- to Jπ=1/2-. These are 'mixed' transitions because they can involve quantum number changes either (/Delta T=1,/ /Delta J=0,/ /Delta/pi=0,/ /Delta S=0), or (/Delta T=1,/ /Delta J=1,/ /Delta/pi=0,/ /Delta S=1); these quantum number changes are refered to as 'Fermi' and 'Gamow-Teller' respectively. Because the quantum number changes are the same as for Fermi and Gamow-Teller beta decay. From the systematics of (p,n) and (n,p) reactions on pure Fermi transitions (e.g. 0 + to 0+) and pure Gamow-Teller transitions (e.g. 0+ to 1+), calibrations have been established of cross section per unit B(F) or unit B(GT), where 'B' refers to doubly reduced matrix elements extracted from beta decay. However, cross sections for the 13C(p,n)13N(g.s.) and 15N(p,n)15O(g.s.) reactions are substantially larger than one would then predict from the known B(F)s and B(GT)s for these transitions. To explore this anomaly, spin observables were used to extract separately the Fermi and Gamow-Teller cross sections for these reactions. To acquire the complete sets of polarization- transfer observables, a new neutron polarimeter was designed, built, commissioned and calibrated. This polarimeter, call the '2π polarimeter' because of its complete azimuthal coverage for scattered neutrons, has very good position and timing resolution (354 ps). The complete sets of spin-transfer coefficients Dij for 13C(p,n)13N (at 0o , 5.5o , and 11o ) and 15N(p,n)15O (at 0o ) at 135 MeV were measured. Following the formalism of Ichimura and Kawahigashi, we extracted the spin-longitudinal, and spin-transverse and spin-independent responses D0,/ Dq,/ Dn and Dp from the measured Dijs. The F and GT fractions of the (p,n) cross sections are then extracted as f F=D0 and fGT=Dn+Dp+Dq=1- d0. Values of Dk for both the 13C(p,n)13N(g.s) and 15N(p,n)15O(g.s.) were extracted. From these responses, we

Task clarification, performance feedback, and social praise: Procedures for improving the customer service of bank tellers

PubMed Central

Crowell, Charles R.; Anderson, D. Chris; Abel, Dawn M.; Sergio, Joseph P.

1988-01-01

Customer service for bank tellers was defined in terms of 11 verbal behavior categories. An audio-recording system was used to track the occurrence of behaviors in these categories for six retail banking tellers. Three behavior management interventions (task clarification, performance feedback, and social praise), applied in sequence, were designed to improve overall teller performance with regard to the behavioral categories targeted. Clarification was accomplished by providing clear delineation of the various target categories, with specific examples of the behaviors in each. Feedback entailed presentation of ongoing verbal and visual information regarding teller performance. Praise consisted of verbal recognition of teller performance by branch managers. Results showed that clarification effects emerged quickly, producing an overall increase in desired behaviors of 12% over baseline. Feedback and praise effects occurred more gradually, resulting in overall increases of 6% and 7%, respectively. A suspension of all procedures led to a decline in overall performance, whereas reinstatement of feedback and praise was again accompanied by performance improvement. These findings extend the generality of behavior management applications and help to distinguish between possible antecedent and consequent effects of performance feedback. PMID:16795713

Science and Technology Review, July-August 1998: Celebrating Edward Teller at 90

DOE R&D Accomplishments Database

Smart, J.

1998-07-01

On the occasion of Edward Teller's 90th birthday, Science and Technology Review (S&TR) has the pleasure of honoring Lawrence Livermore's co-founder and most influential scientist. Teller is known for his inventive work in physics, his concepts leading to thermonuclear explosions, and his strong stands on such issues as science education, the nation's strategic defense, the needs for science in the future, and sharing scientific information. The articles in this issue also show him, as always, tirelessly moving forward with his new and changing interests.

Observation of a quadrupole interaction for cubic imperfections exhibiting a dynamic Jahn-Teller effect.

NASA Technical Reports Server (NTRS)

Herrington, J. R.; Estle, T. L.; Boatner, L. A.

1972-01-01

The observation and interpretation of weak EPR transitions, identified as 'forbidden' transitions, establish the existence of a new type of quadrupole interaction for cubic-symmetry imperfections. This interaction is simply a consequence of the ground-vibronic-state degeneracy. The signs as well as the magnitudes of the quadrupole-coupling coefficients are determined experimentally. These data agree well with the predictions of crystal field theory modified to account for a weak-to-moderate vibronic interaction (i.e., a dynamic Jahn-Teller effect).

Reconnaissance for radioactive deposits in the vicinity of Teller and Cape Nome, Seward Peninsula, Alaska, 1946-47

USGS Publications Warehouse

White, Max Gregg; West, W.S.; Matzko, J.J.

1953-01-01

Placer-mining areas and bedrock exposures near Teller on the Seward Peninsula, Alaska, were investigated in June and July, 1946, for possible sources of radioactive materials. The areas that were investigated are: Dese Creek, southeast of Teller; Bluestone River basin, south and southeast of Teller; Sunset Creek and other small streams flowing south into Grantley Harbor, northeast of Teller; and, also northeast of Teller, Swanson Creek and its tributaries, which flow north into the Agiapuk River basin. No significant amount of radioactive material was found, either in the stream gravels or in the bedrock of any of the areas. A heavy-mineral fraction obtained from a granite boulder probably derived from a bench gravel on Gold Run contains 0. 017 percent equivalent uranium, but the radioactivity is due to allanite and zircon. The types of bedrock tested include schist, slate, and greenstone. Readings on fresh surfaces of rock were the same as, or only slightly above the background count. The maximum radioactivity in stream concentrates is 0. 004 percent equivalent uranium in a sluice concentrate from Sunset Creek.

Gamow–Teller resonances in the {sup 118}Sb compound nucleus: Puzzles of an experiment in Sarov

DOE Office of Scientific and Technical Information (OSTI.GOV)

Urin, M. H., E-mail: urin@theor.mephi.ru

2016-03-15

Contradictory data on the observation of Gamow–Teller resonances in the {sup 118}Sb compound nucleus are discussed along with the available interpretation of these data and planned experimental and theoretical investigations into Gamow–Teller resonances in a number of antimony isotopes.

One of My Favorite Assignments: Automated Teller Machine Simulation.

ERIC Educational Resources Information Center

Oberman, Paul S.

2001-01-01

Describes an assignment for an introductory computer science class that requires the student to write a software program that simulates an automated teller machine. Highlights include an algorithm for the assignment; sample file contents; language features used; assignment variations; and discussion points. (LRW)

Evolution of single-particle structure and beta-decay near 78Ni

NASA Astrophysics Data System (ADS)

Borzov, I. N.

2012-12-01

The extended self-consistent beta-decay model has been applied for bet-decay rates and delayed neutron emission probabilities of spherical neutron-rich isotopes near the r-process paths. Unlike a popular global FRDM+RPA model, in our fully microscopic approach, the Gamow-Teller and first-forbidden decays are treated on the same footing. The model has been augmented by blocking of the odd particle in order to account for important ground-state spin-parity inversion effect which has been shown to exist in the region of the most neutron-rich doubly-magic nucleus 78Ni. Finally, a newly developed form of density functional DF3a has been employed which gives a better spin-orbit splitting due to the modified tensor components of the density functional.

Quantified Gamow shell model interaction for p s d -shell nuclei

NASA Astrophysics Data System (ADS)

Jaganathen, Y.; Betan, R. M. Id; Michel, N.; Nazarewicz, W.; Płoszajczak, M.

2017-11-01

Background: The structure of weakly bound and unbound nuclei close to particle drip lines is one of the major science drivers of nuclear physics. A comprehensive understanding of these systems goes beyond the traditional configuration interaction approach formulated in the Hilbert space of localized states (nuclear shell model) and requires an open quantum system description. The complex-energy Gamow shell model (GSM) provides such a framework as it is capable of describing resonant and nonresonant many-body states on equal footing. Purpose: To make reliable predictions, quality input is needed that allows for the full uncertainty quantification of theoretical results. In this study, we carry out the optimization of an effective GSM (one-body and two-body) interaction in the p s d f -shell-model space. The resulting interaction is expected to describe nuclei with 5 ≤A ≲12 at the p -s d -shell interface. Method: The one-body potential of the 4He core is modeled by a Woods-Saxon + spin-orbit + Coulomb potential, and the finite-range nucleon-nucleon interaction between the valence nucleons consists of central, spin-orbit, tensor, and Coulomb terms. The GSM is used to compute key fit observables. The χ2 optimization is performed using the Gauss-Newton algorithm augmented by the singular value decomposition technique. The resulting covariance matrix enables quantification of statistical errors within the linear regression approach. Results: The optimized one-body potential reproduces nucleon-4He scattering phase shifts up to an excitation energy of 20 MeV. The two-body interaction built on top of the optimized one-body field is adjusted to the bound and unbound ground-state binding energies and selected excited states of the helium, lithium, and beryllium isotopes up to A =9 . A very good agreement with experimental results was obtained for binding energies. First applications of the optimized interaction include predictions for two-nucleon correlation densities

Quantified Gamow shell model interaction for p s d -shell nuclei

DOE PAGES

Jaganathen, Y.; Betan, R. M. Id; Michel, N.; ...

2017-11-20

Background: The structure of weakly bound and unbound nuclei close to particle drip lines is one of the major science drivers of nuclear physics. A comprehensive understanding of these systems goes beyond the traditional configuration interaction approach formulated in the Hilbert space of localized states (nuclear shell model) and requires an open quantum system description. The complex-energy Gamow shell model (GSM) provides such a framework as it is capable of describing resonant and nonresonant many-body states on equal footing. Purpose: To make reliable predictions, quality input is needed that allows for the full uncertainty quantification of theoretical results. In thismore » study, we carry out the optimization of an effective GSM (one-body and two-body) interaction in the psdf-shell-model space. The resulting interaction is expected to describe nuclei with 5 ≤ A ≲ 12 at the p-sd-shell interface. Method: The one-body potential of the 4He core is modeled by a Woods-Saxon + spin-orbit + Coulomb potential, and the finite-range nucleon-nucleon interaction between the valence nucleons consists of central, spin-orbit, tensor, and Coulomb terms. The GSM is used to compute key fit observables. The χ 2 optimization is performed using the Gauss-Newton algorithm augmented by the singular value decomposition technique. The resulting covariance matrix enables quantification of statistical errors within the linear regression approach. Results: The optimized one-body potential reproduces nucleon- 4He scattering phase shifts up to an excitation energy of 20 MeV. The two-body interaction built on top of the optimized one-body field is adjusted to the bound and unbound ground-state binding energies and selected excited states of the helium, lithium, and beryllium isotopes up to A = 9 . A very good agreement with experimental results was obtained for binding energies. First applications of the optimized interaction include predictions for two-nucleon correlation

Nuclear Physics Activities in Asia and ANPhA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakai, H.

2011-05-06

On 18 July 2009 the Asian Nuclear Physics Association (ANPhA) has been officially launched in Beijing by the representatives from China, Korea, Japan and Vietnam. Since then Australia, India, Mongolia and Taiwan have joined to ANPhA and now the member country/region has increased to eight. Some activities and features on ANPhA are introduced. In addition, pleasant collaboration with Professor Arima by the author in regard to the Gamow-Teller quenching problem is also briefly mentioned.

Comment on "Histories and Horoscopes: The Ethnographer as Fortune-Teller."

ERIC Educational Resources Information Center

Luttrell, Wendy

1998-01-01

Explores the analogy of the researcher as fortune teller and the parallels between research histories and horoscopes and discusses the tension between what the subject is and what he or she is imagined to be by others. (SLD)

Soil Physical, Chemical, and Thermal Characterization, Teller Road Site, Seward Peninsula, Alaska, 2016

DOE Data Explorer

Graham, David; Kholodov, Alexander; Wilson, Cathy; Moon, Ji-Won; Romanovsky, Vladimir; Busey, Bob

2018-02-05

This dataset provides the results of physical, chemical, and thermal characterization of soils at the Teller Road Site, Seward Peninsula, Alaska. Soil pits were dug from 7-14 September 2016 at designated Intensive Stations 2 through 9 at the Teller Road MM 27 Site. This dataset includes field observations and descriptions of soil layers or horizons, field measurements of soil volumetric water content, soil temperature, thermal conductivity, and heat capacity. Laboratory measurements of soil properties include gravimetric water content, bulk density, volumetric water content, and total carbon and nitrogen.

The Jahn-Teller effect in (hu+)2⊗hg systems

NASA Astrophysics Data System (ADS)

Hands, Ian D.; Diery, Wajood A.; Dunn, Janette L.; Bates, Colin A.

2007-07-01

A general consideration is made of the vibronic coupling in a (hu+)2⊗hg Jahn-Teller system, that is to say, a system in which two holes of Hu symmetry are coupled to vibrations of hg symmetry. We find that the resulting high-spin states may undergo spontaneous distortion into species exhibiting one of the following four possible symmetries: D5 d, D3 d, D2 h or C2 h. The system may be viewed as a first approximation to a C602+ ion, but our intention here is to make a general consideration of the model without application to any specific molecular system. Coulombic interactions between holes, which must be important in real systems, are therefore ignored throughout. However, they could be included in the model, if required, using the method described in an earlier work [I.D. Hands, J.L. Dunn, W.A. Diery, C.A. Bates, Phys. Rev. B 73 (2006) 115435]. For each of the different symmetry types, projection operators are used to create symmetry-adapted states (SASs) that give a good account of the states of the system over a wide range of coupling strengths. These SASs are used, in turn, to derive energies for the vibronic states.

Impact of electron-captures on nuclei near N = 50 on core-collapse supernovae

NASA Astrophysics Data System (ADS)

Titus, R.; Sullivan, C.; Zegers, R. G. T.; Brown, B. A.; Gao, B.

2018-01-01

The sensitivity of the late stages of stellar core collapse to electron-capture rates on nuclei is investigated, with a focus on electron-capture rates on 74 nuclei with neutron number close to 50, just above doubly magic 78Ni. It is demonstrated that variations in key characteristics of the evolution, such as the lepton fraction, electron fraction, entropy, stellar density, and in-fall velocity are about 50% due to uncertainties in the electron-capture rates on nuclei in this region, although thousands of nuclei are included in the simulations. The present electron-capture rate estimates used for the nuclei in this high-sensitivity region of the chart of isotopes are primarily based on a simple approximation, and it is shown that the estimated rates are likely too high, by an order of magnitude or more. Electron-capture rates based on Gamow-Teller strength distributions calculated in microscopic theoretical models will be required to obtain better estimates. Gamow-Teller distributions extracted from charge-exchange experiments performed at intermediate energies serve to guide the development and benchmark the models. A previously compiled weak-rate library that is used in the astrophysical simulations was updated as part of the work presented here, by adding additional rate tables for nuclei near stability for mass numbers between 60 and 110.

Tz=-1 →0 β decays of 54Ni,50Fe,46Cr, and 42Ti and comparison with mirror (3He,t ) measurements

NASA Astrophysics Data System (ADS)

Molina, F.; Rubio, B.; Fujita, Y.; Gelletly, W.; Agramunt, J.; Algora, A.; Benlliure, J.; Boutachkov, P.; Cáceres, L.; Cakirli, R. B.; Casarejos, E.; Domingo-Pardo, C.; Doornenbal, P.; Gadea, A.; Ganioǧlu, E.; Gascón, M.; Geissel, H.; Gerl, J.; Górska, M.; GrÈ©bosz, J.; Hoischen, R.; Kumar, R.; Kurz, N.; Kojouharov, I.; Susam, L. Amon; Matsubara, H.; Morales, A. I.; Oktem, Y.; Pauwels, D.; Pérez-Loureiro, D.; Pietri, S.; Podolyák, Zs.; Prokopowicz, W.; Rudolph, D.; Schaffner, H.; Steer, S. J.; Tain, J. L.; Tamii, A.; Tashenov, S.; Valiente-Dobón, J. J.; Verma, S.; Wollersheim, H.-J.

2015-01-01

We have studied the β decay of the Tz=-1 ,f7 /2 shell nuclei 54Ni,50Fe,46Cr, and 42Ti produced in fragmentation reactions. The proton separation energies in the daughter Tz=0 nuclei are relatively large (≈4 -5 MeV) so studies of the γ rays are essential. The experiments were performed at GSI as part of the Stopped-beam campaign with the RISING setup consisting of 15 Euroball Cluster Ge detectors. From the newly obtained high precision β -decay half-lives, excitation energies, and β branching ratios, we were able to extract Fermi and Gamow-Teller transition strengths in these β decays. With these improved results it was possible to compare in detail the Gamow-Teller (GT) transition strengths observed in beta decay including a sensitivity limit with the strengths of the Tz=+1 to Tz=0 transitions derived from high resolution (3He ,t ) reactions on the mirror target nuclei at RCNP, Osaka. The accumulated B (GT) strength obtained from both experiments looks very similar although the charge exchange reaction provides information on a broader energy range. Using the "merged analysis" one can obtain a full picture of the B (GT) over the full Qβ range. Looking at the individual transitions some differences are observed, especially for the weak transitions. Their possible origins are discussed.

Visual Display Terminal use in Iranian bank tellers: Effects on job stress and insomnia.

PubMed

Giahi, Omid; Shahmoradi, Behzad; Barkhordari, Abdullah; Khoubi, Jamshid

2015-01-01

Visual Display Terminals (VDTs) are equipments in many workplaces which their use may increase the risk of visual, musculoskeletal and mental problems including insomnia. To determine the relationship between duration of daily VDT use and insomnia among the Iranian bank tellers. We randomly selected 382 bank tellers working with VDT. Quality of sleep and stress information were collected by Athens Insomnia Scales (AIS) and Demand-Control Model (DCM) model respectively. Out of 382 participants, 127 (33.2%) had sleep complaints and 255 (66.8%) had no sleep disorders. Moreover, the insomnia symptoms' score were significantly high in the participants having more than 6 hours of daily VDT use after adjusting for multiple confounding factors (P <  0.001). There was no significant relationship between stress and insomnia. It seems that the low levels of stress and job satisfaction reduce the impact of VDT on sleep quality in tellers who worked less than 6 hours per day.

Star wars and strategic defense initiatives: work activity and health symptoms of unionized bank tellers during work reorganization.

PubMed

Seifert, A M; Messing, K; Dumais, L

1997-01-01

Work activity and health symptoms of bank tellers whose work was undergoing reorganization were examined during a university-union study of the health effects of work in women's traditional jobs. Data were gathered through collective and individual interviews, analysis of work activity, and a questionnaire administered to 305 tellers. Employees worked in a standing posture over 80 percent of the time. More than two-thirds frequently suffered pain in back, legs, and feet. The average teller had been involved in 3.7 robberies as a direct victim and six as a witness. Work required feats of memory and concentration. In order to meet job demands, tellers engaged in supportive activities and teamwork. The introduction of individualized objectives threatened the employees' ability to collaborate and induced distress. More than twice as many tellers as other female workers in Québec experience psychological distress (Ilfeld scale), related to: robbery during the past two years (odds ratio = 1.7; confidence interval = 1.0-2.9); difficult relations with superiors (O.R. = 2.6; C.I. = 1.3-5.3); and full-time work (O.R. = 2.3; C.I. = 1.3-3.9). Diverse methods enriched the analysis, and union participation allowed the proposal of concrete correction measures.

Energy dependence of the ratio of isovector effective interaction strengths |JστJτ| from 0° (p,n) cross sections

NASA Astrophysics Data System (ADS)

Taddeucci, T. N.; Rapaport, J.; Bainum, D. E.; Goodman, C. D.; Foster, C. C.; Gaarde, C.; Larsen, J.; Goulding, C. A.; Horen, D. J.; Masterson, T.; Sugarbaker, E.

1982-02-01

Information concerning the ratio of the isovector effective interaction strengths |JστJτ| may be obtained from the ratio of (p,n) Gamow-Teller and isobaric analog state 0° differential cross sections. We have examined 0° (p,n) data for the energy range 5-200 MeV and find that for energies larger than 50 MeV and for targets with A=7-42 the product of the interaction-strength and distortion-factor ratios |JστJτ|(NστNτ)12 appears to be mass independent and linear as a function of bombarding energy. NUCLEAR REACTIONS 7Li, 13, 14C, 26Mg, 37Cl, 41Ca(p,n), measured σ(θ=0°), GT, IAS transitions, Ep=60-200 MeV. Deduced energy dependence, interaction strength ratio |JστJτ|.

Renner-Teller effects in the photoelectron spectra of CNC, CCN, and HCCN.

PubMed

Coudert, Laurent H; Gans, Bérenger; Garcia, Gustavo A; Loison, Jean-Christophe

2018-02-07

The line intensity of photoelectron spectra when either the neutral or cationic species display a Renner-Teller coupling is derived and applied to the modeling of the photoelectron spectra of CNC, CCN, and HCCN. The rovibronic energy levels of these three radicals and of their cations are investigated starting from ab initio results. A model treating simultaneously the bending mode and the overall rotation is developed to deal with the quasilinearity problem in CNC + , CCN + , and HCCN and accounts for the large amplitude nature of their bending mode. This model is extended to treat the Renner-Teller coupling in CNC, CCN, and HCCN + . Based on the derived photoelectron line intensity, the photoelectron spectra of all three molecules are calculated and compared to the experimental ones.

GMX approximation for the linear E ⊗ ɛ Jahn-Teller effect

NASA Astrophysics Data System (ADS)

Mancini, Jay D.; Fessatidis, Vassilios; Bowen, Samuel P.

2006-02-01

A newly developed generalized moments expansion (GMX) based on the t-expansion of Horn and Weinstein is applied to a linear E ⊗ ɛ Jahn-Teller system. Comparisons are made with other moments schemes as well a coupled cluster approximation.

Teller Training Module: Off-Line Banking System. High-Technology Training Module.

ERIC Educational Resources Information Center

Lund, Candyce J.

This teller training module on offline banking systems is intended to be part of a postsecondary financial applications course. The module contains the following sections: module objective; specific objective; content--electronic audit machine key functions, practice packet--sample bank transactions and practicing procedures, and…

Proton-Proton Fusion and Tritium β Decay from Lattice Quantum Chromodynamics

NASA Astrophysics Data System (ADS)

Savage, Martin J.; Shanahan, Phiala E.; Tiburzi, Brian C.; Wagman, Michael L.; Winter, Frank; Beane, Silas R.; Chang, Emmanuel; Davoudi, Zohreh; Detmold, William; Orginos, Kostas; Nplqcd Collaboration

2017-08-01

The nuclear matrix element determining the p p →d e+ν fusion cross section and the Gamow-Teller matrix element contributing to tritium β decay are calculated with lattice quantum chromodynamics for the first time. Using a new implementation of the background field method, these quantities are calculated at the SU(3) flavor-symmetric value of the quark masses, corresponding to a pion mass of mπ˜806 MeV . The Gamow-Teller matrix element in tritium is found to be 0.979(03)(10) at these quark masses, which is within 2 σ of the experimental value. Assuming that the short-distance correlated two-nucleon contributions to the matrix element (meson-exchange currents) depend only mildly on the quark masses, as seen for the analogous magnetic interactions, the calculated p p →d e+ν transition matrix element leads to a fusion cross section at the physical quark masses that is consistent with its currently accepted value. Moreover, the leading two-nucleon axial counterterm of pionless effective field theory is determined to be L1 ,A=3.9 (0.2 )(1.0 )(0.4 )(0.9 ) fm3 at a renormalization scale set by the physical pion mass, also agreeing within the accepted phenomenological range. This work concretely demonstrates that weak transition amplitudes in few-nucleon systems can be studied directly from the fundamental quark and gluon degrees of freedom and opens the way for subsequent investigations of many important quantities in nuclear physics.

a Zero-Order Picture of the Infrared Spectrum for the Methoxy Radical: Assignment of States

NASA Astrophysics Data System (ADS)

Johnson, Britta; Sibert, Edwin

2016-06-01

The ground tilde{X}^2E vibrations of the methoxy radical have intrigued both experimentalists and theorists alike due to the presence of a conical intersection at the C3v molecular geometry. This conical intersection causes methoxy's vibrational spectrum to be strongly influenced by Jahn-Teller vibronic coupling which leads to large amplitude vibrations and extensive mixing of the two lowest electronic states. This coupling combined with spin-orbit and Fermi couplings greatly complicates the assignments of states. Using the potential force field and calculated spectra of Nagesh and Sibert1,2, we assign quantum numbers to the infrared spectrum. When the zero-order states are the diabatic normal mode states, there is sufficient mode mixing that the normal mode quantum numbers are poor labels for the final states. We define a series of zero-order Hamiltonians which include additional coupling elements beyond the normal mode picture but still allow for the assignment of Jahn-Teller quantum numbers. In methoxy, the two lowest frequency e} modes, the bend (q_5) and the rock (q_6), are the modes with the strongest Jahn-Teller coupling. In general, a zero-order Hamiltonian which includes first-order Jahn-Teller coupling in q_6 is sufficient for most states of interest. Working in a representation which includes first-order Jahn-Teller coupling in q_6, we identify states in which additional coupling elements must be included; these couplings include first-order Jahn-Teller coupling in q_5, higher order Jahn-Teller coupling in q_5 and q_6, and, in the dueterated case, Jahn-Teller coupling which is modulated by the corresponding a modes. [^1] Nagesh, J.; Sibert, E. L. J. Phys. Chem. A 2012, 116, 3846-3855. Lee, Y.F.; Chou, W.T.; Johnson, B.A.; Tabor, D.P. ; Sibert, E.L.; Lee, Y.P. J. Mol. Spectrosc. 2015, 310, 57-67. Barckholtz, T. A.; Miller, T. A. Int. Revs. in Phys. Chem. 1998, 17, 435-524.

Intermediate Nuclear Structure for 2v 2{beta} Decay of {sup 48}Ca Studied by (p, n) and (n, p) Reactions at 300 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakai, H.; Yako, K.

2009-08-26

Angular distributions of the double differential cross sections for the {sup 48}Ca(p,n) and the {sup 48}Ti(n,p) reactions were measured at 300 MeV. A multipole decomposition technique was applied to the spectra to extract the Gamow-Teller (GT) transition strengths. In the (n, p) spectrum beyond 8 MeV excitation energy extra B(GT{sup +}) strengths which are not predicted by the shell model calculation. This extra B(GT{sup +}) strengths significantly contribute to the nuclear matrix element of the 2v2{beta}-decay.

GeneStoryTeller: a mobile app for quick and comprehensive information retrieval of human genes

PubMed Central

Eleftheriou, Stergiani V.; Bourdakou, Marilena M.; Athanasiadis, Emmanouil I.; Spyrou, George M.

2015-01-01

In the last few years, mobile devices such as smartphones and tablets have become an integral part of everyday life, due to their software/hardware rapid development, as well as the increased portability they offer. Nevertheless, up to now, only few Apps have been developed in the field of bioinformatics, capable to perform fast and robust access to services. We have developed the GeneStoryTeller, a mobile application for Android platforms, where users are able to instantly retrieve information regarding any recorded human gene, derived from eight publicly available databases, as a summary story. Complementary information regarding gene–drugs interactions, functional annotation and disease associations for each selected gene is also provided in the gene story. The most challenging part during the development of the GeneStoryTeller was to keep balance between storing data locally within the app and obtaining the updated content dynamically via a network connection. This was accomplished with the implementation of an administrative site where data are curated and synchronized with the application requiring a minimum human intervention. Database URL: http://bioserver-3.bioacademy.gr/Bioserver/GeneStoryTeller/. PMID:26055097

Cyclopropenyl Anions: Carbon Tunneling or Diradical Formation? A Contest between Jahn-Teller and Hund.

PubMed

Kozuch, Sebastian

2015-07-14

The π bond shifting (automerization) by carbon tunneling of cyclopropenyl anions was computationally analyzed by the small curvature tunneling methodology. Similar to other antiaromatic cases, the process is hindered by substituents departing from planarity, since these groups must be realigned along with the π bond shifting. With hydrogens as substituents the tunneling is extremely fast, in a case of both heavy and light atom tunneling. But, with more massive substituents (such as Me and F), and especially with longer groups (such as CN), the tunneling probability is reduced or even virtually canceled. The automerization of triphenylcyclopropyl anion by tunneling was supposed to be impossible due to the high mass of the phenyl groups. However, it was found that the ground state of this species is actually a D3h aromatic triplet, a single-well system that cannot undergo automerization. For this and other systems with π acceptor groups, the superposition of states that generates the second-order Jahn-Teller distortion is diminished, and by Hund's rule, the triplet results in the ground state.

Understanding Two Different Structures in the Dark Stable State of the Oxygen‐Evolving Complex of Photosystem II: Applicability of the Jahn–Teller Deformation Formula

PubMed Central

Shoji, Mitsuo; Isobe, Hiroshi; Tanaka, Ayako; Fukushima, Yoshimasa; Kawakami, Keisuke; Umena, Yasufumi; Kamiya, Nobuo; Nakajima, Takahito

2017-01-01

Abstract Tanaka et al. (J. Am. Chem. Soc., 2017, 139, 1718) recently reported the three‐dimensional (3D) structure of the oxygen evolving complex (OEC) of photosystem II (PSII) by X‐ray diffraction (XRD) using extremely low X‐ray doses of 0.03 and 0.12 MGy. They observed two different 3D structures of the CaMn4O5 cluster with different hydrogen‐bonding interactions in the S1 state of OEC keeping the surrounding polypeptide frameworks of PSII the same. Our Jahn–Teller (JT) deformation formula based on large‐scale quantum mechanics/molecular mechanics (QM/MM) was applied for these low‐dose XRD structures, elucidating important roles of JT effects of the MnIII ion for subtle geometric distortions of the CaMn4O5 cluster in OEC of PSII. The JT deformation formula revealed the similarity between the low‐dose XRD and damage‐free serial femtosecond X‐ray diffraction (SFX) structures of the CaMn4O5 cluster in the dark stable state. The extremely low‐dose XRD structures were not damaged by X‐ray irradiation. Implications of the present results are discussed in relation to recent SFX results and a blue print for the design of artificial photocatalysts for water oxidation. PMID:29577075

Simultaneous effects of pressure and temperature on donor binding energy in Pöschl-Teller quantum well

NASA Astrophysics Data System (ADS)

Hakimyfard, Alireza; Barseghyan, M. G.; Duque, C. A.; Kirakosyan, A. A.

2009-12-01

In the frame of the variational method and the effective-mass approximation, the effects of hydrostatic pressure and temperature on the binding energy for donor impurities in the Pöschl-Teller quantum well are studied. The binding energy dependencies on the width of the quantum well, the hydrostatic pressure, the impurity position, the temperature, and the parameters of the confining potential are reported. The results show that the binding energy increases (decreases) with the increasing of the hydrostatic pressure (temperature). It is also found that, associated with the symmetry breaking in the Pöschl-Teller quantum well, and depending on the impurity position, the binding energy can increase or decrease.

Electron-capture Rates for pf-shell Nuclei in Stellar Environments and Nucleosynthesis

NASA Astrophysics Data System (ADS)

Suzuki, Toshio; Honma, Michio; Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka; Hidakai, Jun; Otsuka, Takaharu

Gamow-Teller strengths in pf-shell nuclei obtained by a new shell-model Hamltonian, GXPF1J, are used to evaluate electron-capture rates in pf-shell nuclei at stellar environments. The nuclear weak rates with GXPF1J, which are generally smaller than previous evaluations for proton-rich nuclei, are applied to nucleosynthesis in type Ia supernova explosions. The updated rates are found to lead to less production of neutron-rich nuclei such as 58Ni and 54Cr, thus toward a solution of the problem of over-production of neutron-rich isotopes of iron-group nuclei compared to the solar abundance.

Probing the N˜Z line via β decay

NASA Astrophysics Data System (ADS)

Oinonen, Markku

1999-11-01

This contribution reports several beta-decay studies performed at ISOLDE On-line Mass Separator at CERN recently for nuclei close to N=Z line. Beta decay of 58Zn provides a possibility to compare Gamow-Teller strength extracted from complementary beta-decay studies and charge-exchange reactions. Measurement on beta-decay half-life of 70Kr shows importance of experimental information in modelling the path of the astrophysical rp process. Decay of 71Kr is an example of a mirror beta decay and extends the systematics of these particular decays towards highly deformed region close to A=80.

Dynamical Jahn Teller distortion in single crystals of Cu(II) doped magnesium potassium phosphate hexahydrate: a variable temperature EPR study

NASA Astrophysics Data System (ADS)

PrabhuKantan, A.; Velavan, K.; Venkatesan, R.; Sambasiva Rao, P.

2003-05-01

Single crystal electron paramagnetic resonance (EPR) studies on Cu(II)-doped magnesium potassium phosphate hexahydrate have been carried out at room temperature. The temperature dependence of g and A values has been obtained for the polycrystalline sample and the ground state is unambiguously identified. These results indicate the existence of a dynamic Jahn-Teller distortion for Cu(II) ion. The g and A tensor direction cosines are evaluated and compared with Mg-O directions, which confirms that Cu(II) enters substitutionally in the lattice.

Jahn-Teller distortion of Mn3+-occupied octahedra in red beryl from Utah indicated by optical spectroscopy

NASA Astrophysics Data System (ADS)

Fridrichová, Jana; Bačík, Peter; Ertl, Andreas; Wildner, Manfred; Dekan, Július; Miglierini, Marcel

2018-01-01

Red beryl from Utah is chemically homogeneous and contains only Fe < 0.163, Mn < 0.018, and Mg < 0.016 apfu. Channel sites contain only up to Cs 0.011, K 0.009, Rb 0.004, and Na 0.004 apfu. This suggests only very slight tetrahedral (Cs,K,Rb)Li□-1Be-1 substitution, octahedral Na(Fe2+,Mg)□-1Al-1 substitution can be excluded. Fe and Mn are trivalent as documented by Mössbauer spectroscopy and optical absorption spectroscopy. Red beryl optimized formula is ∼[(Cs,Rb,K)0.02□0.98]Σ1.00□1.00(Al1.79Fe3+0.16Mn3+0.02Ti4+0.02Mg0.01)Σ2.00Be3(Si6O18). Location of Mn3+ was estimated to the octahedral Al3+ site, other choices are improbable due to the bond-length requirements. No Mn3+-induced Jahn-Teller structural distortion was detected due to site symmetry restrictions and small Mn3+ content. However, optical spectroscopy shows broad band at ∼7190 cm-1 assigned to the excited level of the spin-allowed pseudo-tetragonal split E ground state of elongated six-fold Mn3+ coordination. Crystal field calculations indicate that the local Mn3+ environment complies well with crystal chemical expectations for Jahn-Teller distorted Mn3+O6 octahedra.

Eu/RG absorption and excitation spectroscopy in the solid rare gases: state dependence of crystal field splitting and Jahn-Teller coupling.

PubMed

Byrne, Owen; McCaffrey, John G

2011-03-28

Absorption spectroscopy recorded for annealed samples of matrix-isolated atomic europium reveals a pair of thermally stable sites in Ar and Kr while a single site exists in Xe. Plots of the matrix shifts of the visible s → p bands versus host polarizability, allowed the association of the single site in Xe and the blue sites in Ar and Kr. On the basis of the similar ground state bond lengths expected for the Eu-rare gas (RG) diatomics and the known Na-RG molecules, the blue sites are attributed to Eu occupancy in the smaller tetra-vacancy while the red sites are proposed to arise from hexa-vacancy sites. Both sites are of cubic symmetry, consistent with the pronounced Jahn-Teller structure present on the y(8)P ← a(8)S(7/2) transition for these bands in the three hosts studied. Site-selective excitation spectroscopy has been used to reanalyze complex absorption spectra previously published by Jakob et al. [Phys. Lett. A 57, 67 (1976)] for the near-UV f → d transitions. On the basis that a pair of thermally stable sites exist in solid argon, the occurrence of crystal field splitting has been identified to occur for the J ≥ 5/2 level of the (8)P state when isolated in these two sites with cubic symmetry. From a detailed lineshape analysis, the magnitude of the crystal field splittings on the J = 5/2 level in Ar is found to be 105 and 123 cm(-1) for the red and blue sites, respectively.

Investigating the Human Computer Interaction Problems with Automated Teller Machine Navigation Menus

ERIC Educational Resources Information Center

Curran, Kevin; King, David

2008-01-01

Purpose: The automated teller machine (ATM) has become an integral part of our society. However, using the ATM can often be a frustrating experience as people frequently reinsert cards to conduct multiple transactions. This has led to the research question of whether ATM menus are designed in an optimal manner. This paper aims to address the…

Old Father Story Teller: Grandfather Stories of the Pueblo Native American Indians.

ERIC Educational Resources Information Center

Velarde, Pablita

Pablita Velarde, renowned artist and lecturer, recalls some of the Tewa legends handed down orally through the generations. She heard her grandfather and great-grandfather relate these tales on cold winter evenings at Santa Clara Pueblo when she was a child. The six stories told by Old Father Story Teller are "The Stars," which ties the…

Jahn-Teller versus quantum effects in the spin-orbital material LuVO 3

DOE PAGES

Skoulatos, M.; Toth, S.; Roessli, B.; ...

2015-04-13

In this article, we report on combined neutron and resonant x-ray scattering results, identifying the nature of the spin-orbital ground state and magnetic excitations in LuVO 3 as driven by the orbital parameter. In particular, we distinguish between models based on orbital-Peierls dimerization, taken as a signature of quantum effects in orbitals, and Jahn-Teller distortions, in favor of the latter. In order to solve this long-standing puzzle, polarized neutron beams were employed as a prerequisite in order to solve details of the magnetic structure, which allowed quantitative intensity analysis of extended magnetic-excitation data sets. The results of this detailed studymore » enabled us to draw definite conclusions about the classical versus quantum behavior of orbitals in this system and to discard the previous claims about quantum effects dominating the orbital physics of LuVO 3 and similar systems.« less

Suppression of the cooperative Jahn-Teller distortion and its effect on the Raman octahedra-rotation modes of TbM n1 -xF exO3

NASA Astrophysics Data System (ADS)

Vilarinho, R.; Passos, D. J.; Queirós, E. C.; Tavares, P. B.; Almeida, A.; Weber, M. C.; Guennou, M.; Kreisel, J.; Moreira, J. Agostinho

2018-04-01

This work reports the changes in structure and lattice dynamics induced by substituting the Jahn-Teller-active M n3 + ion by the Jahn-Teller-inactive F e3 + in TbM n1 -xF exO3 over the full composition range. The structural analysis reveals that the amplitude of the cooperative Jahn-Teller distortion decreases linearly from x =0 (pure TbMn O3 ) to x =0.5 , where it is completely suppressed. We then correlate this evolution with the behavior of the Raman modes across the solid solution. In particular, we show that the Raman modes associated with the rotation of octahedra, whose wave number is commonly considered to scale linearly with the tilt angles in orthorhombic Pnma perovskites, are also sensitive to the amplitude of the Jahn-Teller distortion.

β -decay rate of 59Fe in shell burning environment and its influence on the production of 60Fe in a massive star

NASA Astrophysics Data System (ADS)

Li, K. A.; Lam, Y. H.; Qi, C.; Tang, X. D.; Zhang, N. T.

2016-12-01

We deduced the stellar β -decay rate of 59Fe at typical carbon-shell burning temperature by taking the experimental Gamow-Teller transition strengths of the 59Fe excited states. The result is also compared with those derived from large-scale shell model calculations. The new rate is up to a factor of 2.5 lower than the theoretical rate of Fuller, Fowler, and Newman (FFN) and up to a factor of 5 higher than decay rate of Langanke and Martínez-Pinedo (LMP) in the temperature region 0.5 ≤T ≤2 GK. We estimated the impact of the newly determined rate on the synthesis of cosmic γ emitter 60Fe in C-shell burning and explosive C/Ne burning using a one-zone model calculation. Our results show that 59Fe stellar β decay plays an important role in 60Fe nucleosynthesis, even though the uncertainty of the decay rate is rather large due to the error of B (GT) strengths.

Beta decay of exotic TZ = -1, -2 nuclei: the interesting case of 56Zn

NASA Astrophysics Data System (ADS)

Orrigo, S. E. A.; Rubio, B.; Fujita, Y.; Blank, B.; Gelletly, W.; Agramunt, J.; Algora, A.; Ascher, P.; Bilgier, B.; Cáceres, L.; Cakirli, R. B.; Fujita, H.; Ganioğlu, E.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.; Kamalou, O.; Kozer, H. C.; Kucuk, L.; Kurtukian-Nieto, T.; Molina, F.; Popescu, L.; Rogers, A. M.; Susoy, G.; Stodel, C.; Suzuki, T.; Tamii, A.; Thomas, J. C.

2014-03-01

The β decay properties of the Tz = -2, 56Zn isotope and other proton-rich nuclei in the fp-shell have been investigated in an experiment performed at GANIL. The ions were produced in fragmentation reactions and implanted in a double-sided silicon strip detector surrounded by Ge EXOGAM clovers. Preliminary results for 56Zn are presented .The 56Zn decay proceeds mainly by β delayed proton emission, but β delayed gamma rays were also detected. Moreover, the exotic β delayed gamma-proton decay was observed for the first time. The 56Zn half-life and the energy levels populated in the 56Cu daughter have been determined. Knowledge of the gamma de-excitation of the mirror states in 56Co and the comparison with the results of the mirror charge exchange process, the 56Fe(3He,t) reaction (where 56Fe has Tz = +2), were important in the interpretation of the 56Zn decay data. The absolute Fermi and Gamow-Teller strengths have been deduced.

β decay of the exotic Tz=-2 nuclei 48Fe,52Ni , and 56Zn

NASA Astrophysics Data System (ADS)

Orrigo, S. E. A.; Rubio, B.; Fujita, Y.; Gelletly, W.; Agramunt, J.; Algora, A.; Ascher, P.; Bilgier, B.; Blank, B.; Cáceres, L.; Cakirli, R. B.; Ganioǧlu, E.; Gerbaux, M.; Giovinazzo, J.; Grévy, S.; Kamalou, O.; Kozer, H. C.; Kucuk, L.; Kurtukian-Nieto, T.; Molina, F.; Popescu, L.; Rogers, A. M.; Susoy, G.; Stodel, C.; Suzuki, T.; Tamii, A.; Thomas, J. C.

2016-04-01

The results of a study of the β decays of three proton-rich nuclei with Tz=-2 , namely 48Fe,52Ni , and 56Zn, produced in an experiment carried out at GANIL, are reported. In all three cases we have extracted the half-lives and the total β -delayed proton emission branching ratios. We have measured the individual β -delayed protons and β -delayed γ rays and the branching ratios of the corresponding levels. Decay schemes have been determined for the three nuclei, and new energy levels are identified in the daughter nuclei. Competition between β -delayed protons and γ rays is observed in the de-excitation of the T =2 isobaric analog states in all three cases. Absolute Fermi and Gamow-Teller transition strengths have been determined. The mass excesses of the nuclei under study have been deduced. In addition, we discuss in detail the data analysis taking as a test case 56Zn, where the exotic β -delayed γ -proton decay has been observed.

Doublet-spacing enhancement caused by {Lambda}N-{Sigma}N coupling in {sub {Lambda}L}i hypernuclear isotopes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Umeya, Atsushi; Harada, Toru; Research Center for Physics and Mathematics, Osaka Electro-Communication University, Neyagawa, Osaka 572-8530

2011-03-15

We theoretically investigate energy spacings of doublets in {sub {Lambda}L}i hypernuclear isotopes with A=7-10 in shell-model calculations with a {Lambda}N-{Sigma}N coupling effect. The calculated results show that the energy shifts are {Delta}{epsilon}=0.09-0.28 MeV and the {Sigma}-mixing probabilities are P{sub {Sigma}}=0.10%-0.34% in {Lambda} ground states for the isotopes because of the {Lambda}N-{Sigma}N coupling in the first-order perturbation. It is found that the energy spacing of the doublet is enhanced as a neutron number N increases; the contribution of the {Lambda}N-{Sigma}N coupling interaction is comparable to that of the {Lambda}N interaction in the neutron-rich {Lambda} hypernuclei. The coherent mechanism of this doublet-spacingmore » enhancement is also discussed in terms of Fermi-type and Gamow-Teller-type {Lambda}N-{Sigma}N couplings.« less

Assigning the low lying vibronic states of CH3O and CD3O

NASA Astrophysics Data System (ADS)

Johnson, Britta A.; Sibert, Edwin L.

2017-05-01

The assignment of lines in vibrational spectra in strongly mixing systems is considered. Several low lying vibrational states of the ground electronic X˜ 2E state of the CH3O and CD3O radicals are assigned. Jahn-Teller, spin-orbit, and Fermi couplings mix the normal mode states. The mixing complicates the assignment of the infrared spectra using a zero-order normal mode representation. Alternative zero-order representations, which include specific Jahn-Teller couplings, are explored. These representations allow for definitive assignments. In many instances it is possible to plot the wavefunctions on which the assignments are based. The plots, which are shown in the adiabatic representation, allow one to visualize the effects of various higher order couplings. The plots also enable one to visualize the conical seam and its effect on the wavefunctions. The first and the second order Jahn-Teller couplings in the rocking motion dominate the spectral features in CH3O, while first order and modulated first order couplings dominate the spectral features in CD3O. The methods described here are general and can be applied to other Jahn-Teller systems.

Pseudo Jahn-Teller effect in control and rationalization of chemical transformations in two-dimensional compounds

NASA Astrophysics Data System (ADS)

Gorinchoy, N. N.; Bersuker, I. B.

2017-05-01

We show that the pseudo Jahn-Teller effect (PJTE) is instrumental in predicting and rationalizing structural changes in chemical transformations of two-dimensional (2D) molecular systems by means of analyzing the symmetries and electron occupation of the ground and lowest excited electronic states and the energy gap between them, subject to their PJT coupling along the main distortion coordinates. Special attention is paid to rationalizing the PJTE origin of non-planarity of 2D compounds and to the restoration of their planar configurations. Examples of two series of 1,2- and 1,4-dithiin containing tricyclic compounds (carbon sulfide, thianthrene, and antracene and their derivatives) are used to demonstrate in detail the mechanism of (1) enhancement and suppression of the PJTE distortions (puckering) in redox processes, and (2) PJTE induced symmetry breaking and restoration of the planar configuration by chemical substitutions.

The temperature dependence of the pressure switching of Jahn Teller deformation in the deuterated ammonium copper Tutton salt

NASA Astrophysics Data System (ADS)

Augustyniak, Maria A.; Krupski, Marcin

1999-09-01

The pressure switch of the Jahn-Teller deformation direction in (ND 4) 2Cu(SO 4) 2·6D 2O was investigated in the temperature range 130-320 K. Below 295 K, the new, pressure-induced phase, is stable under ambient pressure. Switching back is observed on heating to above 297 K. In the range 150-295 K a strong temperature dependence of the switching pressure (from 24 to 450 MPa) is observed. Below 150 K, the switching process is slow and a coexistence of two phases is observed. We conclude that the switch of the Cu(D 2O) 6 complex deformation direction is the Jahn-Teller response to the changes in the hydrogen bond system.

Speckle in the diffraction patterns of Hendricks-Teller and icosahedral glass models

NASA Technical Reports Server (NTRS)

Garg, Anupam; Levine, Dov

1988-01-01

It is shown that the X-ray diffraction patterns from the Hendricks-Teller model for layered systems and the icosahedral glass models for the icosahedral phases show large fluctuations between nearby scattering wave vectors and from sample to sample, that are quite analogous to laser speckle. The statistics of these fluctuations are studied analytically for the first model and via computer simulations for the second. The observability of these effects is discussed briefly.

AES Cardless Automatic Teller Machine (ATM) Biometric Security System Design Using FPGA Implementation

NASA Astrophysics Data System (ADS)

Ahmad, Nabihah; Rifen, A. Aminurdin M.; Helmy Abd Wahab, Mohd

2016-11-01

Automated Teller Machine (ATM) is an electronic banking outlet that allows bank customers to complete a banking transactions without the aid of any bank official or teller. Several problems are associated with the use of ATM card such card cloning, card damaging, card expiring, cast skimming, cost of issuance and maintenance and accessing customer account by third parties. The aim of this project is to give a freedom to the user by changing the card to biometric security system to access the bank account using Advanced Encryption Standard (AES) algorithm. The project is implemented using Field Programmable Gate Array (FPGA) DE2-115 board with Cyclone IV device, fingerprint scanner, and Multi-Touch Liquid Crystal Display (LCD) Second Edition (MTL2) using Very High Speed Integrated Circuit Hardware (VHSIC) Description Language (VHDL). This project used 128-bits AES for recommend the device with the throughput around 19.016Gbps and utilized around 520 slices. This design offers a secure banking transaction with a low rea and high performance and very suited for restricted space environments for small amounts of RAM or ROM where either encryption or decryption is performed.

Jahn-Teller effect in molecular electronics: quantum cellular automata

NASA Astrophysics Data System (ADS)

Tsukerblat, B.; Palii, A.; Clemente-Juan, J. M.; Coronado, E.

2017-05-01

The article summarizes the main results of application of the theory of the Jahn-Teller (JT) and pseudo JT effects to the description of molecular quantum dot cellular automata (QCA), a new paradigm of quantum computing. The following issues are discussed: 1) QCA as a new paradigm of quantum computing, principles and advantages; 2) molecular implementation of QCA; 3) role of the JT effect in charge trapping, encoding of binary information in the quantum cell and non-linear cell-cell response; 4) spin-switching in molecular QCA based on mixed-valence cell; 5) intervalence optical absorption in tetrameric molecular mixed-valence cell through the symmetry assisted approach to the multimode/multilevel JT and pseudo JT problems.

Electron capture rates in stars studied with heavy ion charge exchange reactions

NASA Astrophysics Data System (ADS)

Bertulani, C. A.

2018-01-01

Indirect methods using nucleus-nucleus reactions at high energies (here, high energies mean ~ 50 MeV/nucleon and higher) are now routinely used to extract information of interest for nuclear astrophysics. This is of extreme relevance as many of the nuclei involved in stellar evolution are short-lived. Therefore, indirect methods became the focus of recent studies carried out in major nuclear physics facilities. Among such methods, heavy ion charge exchange is thought to be a useful tool to infer Gamow-Teller matrix elements needed to describe electron capture rates in stars and also double beta-decay experiments. In this short review, I provide a theoretical guidance based on a simple reaction model for charge exchange reactions.

Ab initio theory of spin-orbit coupling for quantum bits in diamond exhibiting dynamic Jahn-Teller effect

NASA Astrophysics Data System (ADS)

Gali, Adam; Thiering, Gergő

Dopants in solids are promising candidates for implementations of quantum bits for quantum computing. In particular, the high-spin negatively charged nitrogen-vacancy defect (NV) in diamond has become a leading contender in solid-state quantum information processing. The initialization and readout of the spin is based on the spin-selective decay of the photo-excited electron to the ground state which is mediated by spin-orbit coupling between excited states states and phonons. Generally, the spin-orbit coupling plays a crucial role in the optical spinpolarization and readout of NV quantum bit (qubit) and alike. Strong electron-phonon coupling in dynamic Jahn-Teller (DJT) systems can substantially influence the effective strength of spin-orbit coupling. Here we show by ab initio supercell density functional theory (DFT) calculations that the intrinsic spin-orbit coupling is strongly damped by DJT effect in the triplet excited state that has a consequence on the rate of non-radiative decay. This theory is applied to the ground state of silicon-vacancy (SiV) and germanium-vacancy (GeV) centers in their negatively charged state that can also act like qubits. We show that the intrinsic spin-orbit coupling in SiV and GeV centers is in the 100 GHz region, in contrast to the NV center of 10 GHz region. Our results provide deep insight in the nature of SiV and GeV qubits in diamond. EU FP7 DIADEMS project (Contract No. 611143).

New Baxter phase in the Ashkin-Teller model on a cubic lattice

NASA Astrophysics Data System (ADS)

Santos, J. P.; Rosa, D. S.; Sá Barreto, F. C.

2018-02-01

The mean field theory results are obtained from the Bogoliubov inequality for the spin-1/2 Ashkin-Teller model on a cubic lattice for different cluster sizes. The phase diagram, magnetization and free energy are obtained. From those expressions we observed a new phase in the model. Denoted in the course of this work by Baxter(2) this new phase presents 〈 S 〉 ≠ 〈 σ 〉 ≠ 0. The phase transitions between the Baxter(2) and the others well known phases for the model are studied and classified.

High-Resolution Laser Spectroscopy of Free Radicals in Nearly Degenerate Electronic States

NASA Astrophysics Data System (ADS)

Liu, Jinjun

2017-06-01

Rovibronic structure of molecules in orbitally degenerate electronic states including Renner-Teller (RT) and Jahn-Teller (JT) active molecules has been extensively studied. Less is known about rotational structure of polyatomic molecules in nearly degenerate states, especially those with low (e.g., C_s) symmetry that are subject to the pseudo-Jahn-Teller (pJT) effect. In the case of free radicals, the unpaired electron further complicates energy levels by inducing spin-orbit (SO) and spin-rotation (SR) splittings. Asymmetric deuteration or methyl substitution of C_{3v} free radicals such as CH_3O, CaCH_3, and CaOCH_3 lowers the molecular symmetry, lifts the vibronic degeneracy, and reduces the JT effect to the pJT effect. New spectroscopic models are required to reproduce the rovibronic structure and simulate the experimentally obtained spectra of pJT-active free radicals. It has been found that rotational and fine-structure analysis of spectra involving nearly degenerate states may aid in vibronic analysis and interpretation of effective molecular constants. Especially, SO and Coriolis interactions that couple the two states can be determined accurately from fitting the experimental spectra. Coupling between the two electronic states also affects the intensities of rotational and vibronic transitions. The study on free radicals in nearly degenerate states provides a promising avenue of research which may bridge the gap between symmetry-induced degenerate states and the Born-Oppenheimer (BO) limit of unperturbed electronic states.

Teaching the Jahn-Teller Theorem: A Simple Exercise That Illustrates How the Magnitude of Distortion Depends on the Number of Electrons and Their Occupation of the Degenerate Energy Level

ERIC Educational Resources Information Center

Johansson, Adam Johannes

2013-01-01

Teaching the Jahn-Teller theorem offers several challenges. For many students, the first encounter comes in coordination chemistry, which can be difficult due to the already complicated nature of transition-metal complexes. Moreover, a deep understanding of the Jahn-Teller theorem requires that one is well acquainted with quantum mechanics and…

An ab initio global potential-energy surface for NH2(A(2)A') and vibrational spectrum of the Renner-Teller A(2)A'-X(2)A" system.

PubMed

Zhou, Shulan; Li, Zheng; Xie, Daiqian; Lin, Shi Ying; Guo, Hua

2009-05-14

A global potential-energy surface for the first excited electronic state of NH(2)(A(2)A(')) has been constructed by three-dimensional cubic spline interpolation of more than 20,000 ab initio points, which were calculated at the multireference configuration-interaction level with the Davidson correction using the augmented correlation-consistent polarized valence quadruple-zeta basis set. The (J=0) vibrational energy levels for the ground (X(2)A(")) and excited (A(2)A(')) electronic states of NH(2) were calculated on our potential-energy surfaces with the diagonal Renner-Teller terms. The results show a good agreement with the experimental vibrational frequencies of NH(2) and its isotopomers.

Ab initio EPR parameters for dangling-bond defect complexes in silicon: Effect of Jahn-Teller distortion

NASA Astrophysics Data System (ADS)

Pfanner, Gernot; Freysoldt, Christoph; Neugebauer, Jörg; Gerstmann, Uwe

2012-05-01

A dangling bond (db) is an important point defect in silicon. It is realized in crystalline silicon by defect complexes of the monovacancy V with impurities. In this work, we present spin-polarized density-functional theory calculations of EPR parameters (g and hyperfine tensors) within the GIPAW formalism for two kinds of db defect complexes. The first class characterizes chemically saturated db systems, where three of the four dangling bonds of the isolated vacancy are saturated by hydrogen (VH3) or hydrogen and oxygen (hydrogen-oxygen complex, VOH). The second kind of db consists of systems with a Jahn-Teller distortion, where the vacancy includes either a substitutional phosphorus atom (the E center, VP) or a single hydrogen atom (VH). For all systems we obtain excellent agreement with available experimental data, and we are therefore able to quantify the effect of the Jahn-Teller distortion on the EPR parameters. Furthermore we study the influence of strain to obtain further insights into the structural and electronic characteristics of the considered defects.

Weak-interaction rates in stellar conditions

NASA Astrophysics Data System (ADS)

Sarriguren, Pedro

2018-05-01

Weak-interaction rates, including β-decay and electron captures, are studied in several mass regions at various densities and temperatures of astrophysical interest. In particular, we study odd-A nuclei in the pf-shell region, which are involved in presupernova formations. Weak rates are relevant to understand the late stages of the stellar evolution, as well as the nucleosynthesis of heavy nuclei. The nuclear structure involved in the weak processes is studied within a quasiparticle proton-neutron random-phase approximation with residual interactions in both particle-hole and particle-particle channels on top of a deformed Skyrme Hartree-Fock mean field with pairing correlations. First, the energy distributions of the Gamow-Teller strength are discussed and compared with the available experimental information, measured under terrestrial conditions from charge-exchange reactions. Then, the sensitivity of the weak-interaction rates to both astrophysical densities and temperatures is studied. Special attention is paid to the relative contribution to these rates of thermally populated excited states in the decaying nucleus and to the electron captures from the degenerate electron plasma.

GeneStoryTeller: a mobile app for quick and comprehensive information retrieval of human genes.

PubMed

Eleftheriou, Stergiani V; Bourdakou, Marilena M; Athanasiadis, Emmanouil I; Spyrou, George M

2015-01-01

In the last few years, mobile devices such as smartphones and tablets have become an integral part of everyday life, due to their software/hardware rapid development, as well as the increased portability they offer. Nevertheless, up to now, only few Apps have been developed in the field of bioinformatics, capable to perform fast and robust access to services. We have developed the GeneStoryTeller, a mobile application for Android platforms, where users are able to instantly retrieve information regarding any recorded human gene, derived from eight publicly available databases, as a summary story. Complementary information regarding gene-drugs interactions, functional annotation and disease associations for each selected gene is also provided in the gene story. The most challenging part during the development of the GeneStoryTeller was to keep balance between storing data locally within the app and obtaining the updated content dynamically via a network connection. This was accomplished with the implementation of an administrative site where data are curated and synchronized with the application requiring a minimum human intervention. © The Author(s) 2015. Published by Oxford University Press.

Jahn-Teller transition in TiF3 investigated using density-functional theory

NASA Astrophysics Data System (ADS)

Perebeinos, Vasili; Vogt, Tom

2004-03-01

We use first-principles density-functional theory to calculate the electronic and magnetic properties of TiF3 using the full-potential-linearized augmented-plane-wave method. The local density approximation (LDA) predicts a fully saturated ferromagnetic metal and finds degenerate energy minima for high- and low-symmetry structures. The experimentally observed Jahn-Teller phase transition at Tc=370 K cannot be driven by the electron-phonon interaction alone, which is usually described accurately by the LDA. Electron correlations beyond the LDA are essential to lift the degeneracy of the singly occupied Ti t2g orbital. Although the on-site Coulomb correlations are important, the direction of the t2g-level splitting is determined by dipole-dipole interactions. The LDA+U functional predicts an aniferromagnetic insulator with an orbitally ordered ground state. The input parameters U=8.1 eV and J=0.9 eV for the Ti 3d orbital were found by varying the total charge on the TiF2-6 ion using the molecular NRLMOL code. We estimate the Heisenberg exchange constant for spin 1/2 on a cubic lattice to be approximately 24 K. The symmetry lowering energy in LDA+U is about 900 K per TiF3 formula unit.

High energy-resolution measurement of the Se 82 ( He 3 , t ) Br 82 reaction for double- β decay and for solar neutrinos

DOE PAGES

Frekers, D.; Alanssari, M.; Adachi, T.; ...

2016-07-21

For this study, a high-resolution ( 3He,t) charge-exchange experiment at an incident energy of 420 MeV has been performed on the double beta (ββ) decay nucleus 82Se. A detailed Gamow-Teller (GT -) strength distribution in 82Br has been extracted, which provides information to the ββ-decay nuclear matrix elements. Three strong and isolated transitions, which are to the 75, 1484 and the 2087 keV states in 82Br, are found to dominate the low-excitation region below ≈ 2.1 MeV. Above 2.1 MeV a sudden onset of a strong GT fragmentation is observed. The degree of fragmentation resembles a situation found in themore » neighboring A = 76 system 76Ge, whereas the observed concentration of strength in the three low-lying states is reminiscent of the heavier neighbors 96Zr and 100Mo. The strong GT transition to the 75 keV (1 +) state makes 82Se interesting for solar neutrino detection. The 82Se(ν e,e -) 82Br solar neutrino capture rate in a nonoscillation scenario is therefore evaluated to 668 ± 12(stat) ± 60(sys) SNU, and some of the advantages of using selenium for solar neutrino studies are discussed.« less

Beta-decay rate and beta-delayed neutron emission probability of improved gross theory

NASA Astrophysics Data System (ADS)

Koura, Hiroyuki

2014-09-01

A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for unmeasured nuclei are adopted from the KTUY nuclear mass formula, which is based on the spherical-basis method. Considering the properties of the integrated Fermi function, we can roughly categorized energy region of excited-state of a daughter nucleus into three regions: a highly-excited energy region, which fully affect a delayed neutron probability, a middle energy region, which is estimated to contribute the decay heat, and a region neighboring the ground-state, which determines the beta-decay rate. Some results will be given in the presentation. A theoretical study has been carried out on beta-decay rate and beta-delayed neutron emission probability. The gross theory of the beta decay is based on an idea of the sum rule of the beta-decay strength function, and has succeeded in describing beta-decay half-lives of nuclei overall nuclear mass region. The gross theory includes not only the allowed transition as the Fermi and the Gamow-Teller, but also the first-forbidden transition. In this work, some improvements are introduced as the nuclear shell correction on nuclear level densities and the nuclear deformation for nuclear strength functions, those effects were not included in the original gross theory. The shell energy and the nuclear deformation for

Leaf Mass Area, Leaf Carbon and Nitrogen Content, Kougarok Road and Teller Road, Seward Peninsula, Alaska, 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shawn Serbin; Alistair Rogers; Kim Ely

Carbon, Nitrogen and Leaf Mass Area of leaves sampled from locations on the Kougarok Rd (transect A) and Teller Rd NGEE Arctic study sites, Seward Peninsula, Alaska. Species include: Alnus viridis spp. fruticosa, Arctostaphylos rubra, Betula glandulosa, Chamerion latifolium, Petasites frigidus, Salix alaxensis, Salix glauca, Salix pulchra, Salix richardsonii and Vaccinium uliginosum.

Spin-flip isovector giant resonances from the 90Zr(n,p)90Y reaction at 198 MeV

NASA Astrophysics Data System (ADS)

Raywood, K. J.; Spicer, B. M.; Yen, S.; Long, S. A.; Moinester, M. A.; Abegg, R.; Alford, W. P.; Celler, A.; Drake, T. E.; Frekers, D.; Green, P. E.; Häusser, O.; Helmer, R. L.; Henderson, R. S.; Hicks, K. H.; Jackson, K. P.; Jeppesen, R. G.; King, J. D.; King, N. S.; Miller, C. A.; Officer, V. C.; Schubank, R.; Shute, G. G.; Vetterli, M.; Watson, J.; Yavin, A. I.

1990-06-01

Doubly differential cross sections of the reaction 90Zr(n,p)90Y have been measured at 198 MeV for excitations up to 38 MeV in the residual nucleus. An overall resolution of 1.3 MeV was achieved. The spectra show qualitative agreement in shape and magnitude with recent random phase approximation calculations; however, all of the calculations underestimate the high excitation region of the spectra. A multipole decomposition of the data has been performed using differential cross sections calculated in the distorted-wave impulse approximation. An estimate of the Gamow-Teller strength in the reaction is given. The isovector spin-flip dipole giant resonance has been identified and there is also an indication of isovector monopole strength.

High Precision Determination of the β Decay QEC Value of 11C and Implications on the Tests of the Standard Model

NASA Astrophysics Data System (ADS)

Gulyuz, K.; Bollen, G.; Brodeur, M.; Bryce, R. A.; Cooper, K.; Eibach, M.; Izzo, C.; Kwan, E.; Manukyan, K.; Morrissey, D. J.; Naviliat-Cuncic, O.; Redshaw, M.; Ringle, R.; Sandler, R.; Schwarz, S.; Sumithrarachchi, C. S.; Valverde, A. A.; Villari, A. C. C.

2016-01-01

We report the determination of the QEC value of the mirror transition of 11C by measuring the atomic masses of 11C and 11B using Penning trap mass spectrometry. More than an order of magnitude improvement in precision is achieved as compared to the 2012 Atomic Mass Evaluation (Ame2012) [Chin. Phys. C 36, 1603 (2012)]. This leads to a factor of 3 improvement in the calculated F t value. Using the new value, QEC=1981.690 (61 ) keV , the uncertainty on F t is no longer dominated by the uncertainty on the QEC value. Based on this measurement, we provide an updated estimate of the Gamow-Teller to Fermi mixing ratio and standard model values of the correlation coefficients.

High Precision Determination of the β Decay Q(EC) Value of (11)C and Implications on the Tests of the Standard Model.

PubMed

Gulyuz, K; Bollen, G; Brodeur, M; Bryce, R A; Cooper, K; Eibach, M; Izzo, C; Kwan, E; Manukyan, K; Morrissey, D J; Naviliat-Cuncic, O; Redshaw, M; Ringle, R; Sandler, R; Schwarz, S; Sumithrarachchi, C S; Valverde, A A; Villari, A C C

2016-01-08

We report the determination of the Q(EC) value of the mirror transition of (11)C by measuring the atomic masses of (11)C and (11)B using Penning trap mass spectrometry. More than an order of magnitude improvement in precision is achieved as compared to the 2012 Atomic Mass Evaluation (Ame2012) [Chin. Phys. C 36, 1603 (2012)]. This leads to a factor of 3 improvement in the calculated Ft value. Using the new value, Q(EC)=1981.690(61)  keV, the uncertainty on Ft is no longer dominated by the uncertainty on the Q(EC) value. Based on this measurement, we provide an updated estimate of the Gamow-Teller to Fermi mixing ratio and standard model values of the correlation coefficients.

Configuration interaction calculations for the region of 76Ge

NASA Astrophysics Data System (ADS)

Brown, Alex

2017-09-01

I will present a short history of the configuration interaction Hamiltonians that have been developed for the (0f5 / 2 , 1p3 / 2 , 1p1 / 2 , 0g9 / 2) (jj 44) model space. This model space is appropriate for the region of nuclei bounded by the nickel isotopes for Z = 28 and the isotones with N = 50 . I will discuss results for the double-beta decay of 76Ge that lies in the jj 44 region. I will show results for the structure of nuclei around 76Ge for some selected data from gamma decay, Gamow-Teller beta decay, charge-exchange reactions, one-nucleon transfer reactions, and two-nucleon transfer reactions. This work was supported by NSF Grant PHY-1404442.

Initial Development and Testing of a State-of-the-Art Method to Quantify Hydrologic Model Uncertainty

DTIC Science & Technology

2013-09-01

H. Teller , and E. Teller . 1953. Equation of state calculations by fast computing machines . J Chem Phys, 21: 1087-1092. Skahill, B. E. 2012. Practice...of DE-MC sampler burn-in, a hybrid semi- automated approach was implemented, consistent with available guidance regarding practical application of...treatment of jump proposal dimensions that are out of bounds, and a hybrid, heuristic, semi- automated approach for assessing convergence of the DE-MC

First-Principles Study of the Jahn-Teller Distortion in the Ti1-XVXH2 and Zr1-XNbxH2 Alloys

NASA Astrophysics Data System (ADS)

Quijano, Ramiro; de Coss, Romeo; Singh, David

2008-03-01

The transition metal dihydrides TiH2 and ZrH2 present the fluorite structure (CaF2) at high temperature but undergoes a tetragonal distortion with c/a<1 at low temperature. Electronic band structure calculations have shown that TiH2 and ZrH2 in the cubic phase display a very flat band at the Fermi level. Thus the low temperature tetragonal distortion has been associated to a Jahn-Teller effect. In order to understand the role of band filling in controlling the structural instability of the transition metal dihydrides, we have performed a first-principles total energy study of the Ti1-XVxH2 and Zr1-xNbxH2 alloys. The calculations were performed using FP-LAPW method within the (DFT) and we use the GGA for exchange correlation functional energy. The critical concentration for which the Jahn-Teller effect is suppressed, was determined from the evolution of the tetragonal-cubic energy barrier. We discuss the electronic mechanism of the structural-instability, in terms of the band filling. From the obtained results we conclude that the tetragonal distortion in TiH2 and ZrH2 is not produced only by a Jahn-Teller Effect. This research was supported by Consejo Nacional de Ciencia y Tecnolog'ia (Conacyt) under Grant No. 43830-F.

Low-spin structure of 51,35,86Br and 50,36,86Kr nuclei: The role of the g7 /2 neutron orbital

NASA Astrophysics Data System (ADS)

Urban, W.; Sieja, K.; Materna, T.; Czerwiński, M.; Rząca-Urban, T.; Blanc, A.; Jentschel, M.; Mutti, P.; Köster, U.; Soldner, T.; de France, G.; Simpson, G. S.; Ur, C. A.; Bernards, C.; Fransen, C.; Jolie, J.; Regis, J.-M.; Thomas, T.; Warr, N.

2016-10-01

Low-spin excited levels in 51,35,86Br and 50,36,86Kr, populated following β- decay and the neutron-induced fission of 235U, were measured using the Lohengrin fission-fragment separator and the EXILL array of Ge detectors at the PF1B cold-neutron facility of the Institute Laue-Langevin Grenoble. Improved populations of excited levels in 86Br remove inconsistencies existing in the literature on this nucleus. Directional-linear-polarization correlations, analyzed using newly developed formulas, as well as precise angular correlations allowed the unique 1- and 2- spin and parity assignments to the ground state of 86Br and the 4016.3-keV level in 86Kr, respectively. Based on these results we propose that the Gamow-Teller β- decays of 86Se and 86Br involve the ν g7 /2→π g9 /2 transition in addition to the ν p3 /2→π p3 /2 transition proposed earlier. In 86Kr we have identified 11+, 23+, and 31+ levels, analogous to the mixed-symmetry states in 94Mo, which in 86Kr are from proton excitations, only. Large-scale, shell-model calculations with refined interactions reproduce well excitations in 86Br and 86Kr and support our interpretations.

Enhanced way of securing automated teller machine to track the misusers using secure monitor tracking analysis

NASA Astrophysics Data System (ADS)

Sadhasivam, Jayakumar; Alamelu, M.; Radhika, R.; Ramya, S.; Dharani, K.; Jayavel, Senthil

2017-11-01

Now a days the people's attraction towards Automated Teller Machine(ATM) has been increasing even in rural areas. As of now the security provided by all the bank is ATM pin number. Hackers know the way to easily identify the pin number and withdraw money if they haven stolen the ATM card. Also, the Automated Teller Machine is broken and the money is stolen. To overcome these disadvantages, we propose an approach “Automated Secure Tracking System” to secure and tracking the changes in ATM. In this approach, while creating the bank account, the bank should scan the iris known (a part or movement of our eye) and fingerprint of the customer. The scanning can be done with the position of the eye movements and fingerprints identified with the shortest measurements. When the card is swiped then ATM should request the pin, scan the iris and recognize the fingerprint and then allow the customer to withdraw money. If somebody tries to break the ATM an alert message is given to the nearby police station and the ATM shutter is automatically closed. This helps in avoiding the hackers who withdraw money by stealing the ATM card and also helps the government in identifying the criminals easily.

What makes an automated teller machine usable by blind users?

PubMed

Manzke, J M; Egan, D H; Felix, D; Krueger, H

1998-07-01

Fifteen blind and sighted subjects, who featured as a control group for acceptance, were asked for their requirements for automated teller machines (ATMs). Both groups also tested the usability of a partially operational ATM mock-up. This machine was based on an existing cash dispenser, providing natural speech output, different function menus and different key arrangements. Performance and subjective evaluation data of blind and sighted subjects were collected. All blind subjects were able to operate the ATM successfully. The implemented speech output was the main usability factor for them. The different interface designs did not significantly affect performance and subjective evaluation. Nevertheless, design recommendations can be derived from the requirement assessment. The sighted subjects were rather open for design modifications, especially the implementation of speech output. However, there was also a mismatch of the requirements of the two subject groups, mainly concerning the key arrangement.

Jahn–Teller Assisted Na Diffusion for High Performance Na Ion Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xin; Wang, Yan; Wu, Di

2016-08-30

Na energy storage technology is strategically attractive for large scale applications such as grid energy storage. Here, we show in this paper that there is a clear relation between the Jahn$-$Teller activity of a transition metal ion at the end of charge and the mobility of Na in a cathode material. This is particularly important as mobility at the end of charge limits the capacity of current materials. Consequently, by using this classical piece of physics in the battery world, it is possible to create higher capacity Na-cathode materials. Even more exciting is that the ideal element to impart thismore » effect on cathodes is Fe, which is the least expensive of the transition metal oxides and can therefore enable low cost cathode materials.« less

EPR Studies of orthorhombic Jahn-Teller effect in single crystal of ferroelectric Cu(II):Cd2(NH4)2 (SO4)3

NASA Astrophysics Data System (ADS)

Benson, Yerima; de, Dilip

In this paper we report the first EPR observation and theoretical explanation of orthorhombic Jahn-Teller effect in Cu(II) doped single crystal of ferroelectric cadmium ammonium sulphate: Cu(II):Cd2(NH4)2 (SO4)3 . The isotropic EPR spectra of the 2D ion (in regular octahedral symmetry) at higher temperature becomes anisotropic at low temperature with clear manifestation of orthorhombic g and hyperfine tensors at 15 K. The static Jahn-Teller(JT) effect can only be explained theoretically by assuming the three JT potential wells energetically inequivalent, unlike the potential wells in most of the Cu(II) doped crystalline materials where JT effect manifests. The measured splitting of the JT potential wells in this ferroelectric crystal fall in the sub millimeter wave region pointing to possible application of the material.

Neutrino nuclear responses for double beta decays and astro neutrinos by charge exchange reactions

NASA Astrophysics Data System (ADS)

Ejiri, Hiroyasu

2014-09-01

Neutrino nuclear responses are crucial for neutrino studies in nuclei. Charge exchange reactions (CER) are shown to be used to study charged current neutrino nuclear responses associated with double beta decays(DBD)and astro neutrino interactions. CERs to be used are high energy-resolution (He3 ,t) reactions at RCNP, photonuclear reactions via IAR at NewSUBARU and muon capture reactions at MUSIC RCNP and MLF J-PARC. The Gamow Teller (GT) strengths studied by CERs reproduce the observed 2 neutrino DBD matrix elements. The GT and spin dipole (SD) matrix elements are found to be reduced much due to the nucleon spin isospin correlations and the non-nucleonic (delta isobar) nuclear medium effects. Impacts of the reductions on the DBD matrix elements and astro neutrino interactions are discussed.

Uncertainties in modeling low-energy neutrino-induced reactions on iron-group nuclei

NASA Astrophysics Data System (ADS)

Paar, N.; Suzuki, T.; Honma, M.; Marketin, T.; Vretenar, D.

2011-10-01

Charged-current neutrino-nucleus cross sections for 54,56Fe and 58,60Ni are calculated and compared using frameworks based on relativistic and Skyrme energy-density functionals and on the shell model. The current theoretical uncertainties in modeling neutrino-nucleus cross sections are assessed in relation to the predicted Gamow-Teller transition strength and available data, to multipole decomposition of the cross sections, and to cross sections averaged over the Michel flux and Fermi-Dirac distribution. By employing different microscopic approaches and models, the decay-at-rest (DAR) neutrino-56Fe cross section and its theoretical uncertainty are estimated to be <σ>th=(258±57)×10-42cm2, in very good agreement with the experimental value <σ>exp=(256±108±43)×10-42cm2.

76 FR 6640 - Advantage Life Products, Inc., and B-Teller, Inc. (n/k/a CA Goldfields, Inc.), Order of...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-07

..., Inc. (n/k/a CA Goldfields, Inc.), Order of Suspension of Trading February 3, 2011. It appears to the... current and accurate information concerning the securities of B-Teller, Inc. (n/k/a CA Goldfields, Inc...(k) of the Securities Exchange Act of 1934, that trading in the securities of the above-listed...

Representing the Quantum Object Through Fiction in Teaching. The Ontological Contribution of Gamow's Narrative as Part of an Introduction to Quantum Physics

NASA Astrophysics Data System (ADS)

Héraud, Jean-Loup; Lautesse, Philippe; Ferlin, Fabrice; Chabot, Hugues

2017-05-01

Our work extends a previous study of epistemological presuppositions in teaching quantum physics in upper scientific secondary school in France. Here, the problematic reference of quantum theory's concepts is treated at the ontological level (the counterintuitive nature of quantum objects). We consider the approach of using narratives describing possible alternative worlds to address the issue. These possible worlds are based on the counterfactual logic developed in the work of D. Lewis. We will show that the narratives written by G. Gamow describe such possible worlds. Some parts of these narratives are found in textbooks in France. These worlds are governed by laws similar to but importantly different from those in our real world. They allow us to materialize properties inaccessible to everyday experience. In this sense, these fiction stories make ontological propositions concerning the nature and structure of the fundamental elements of our physical universe.

Application of polynomial su(1, 1) algebra to Pöschl-Teller potentials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Hong-Biao, E-mail: zhanghb017@nenu.edu.cn; Lu, Lu

2013-12-15

Two novel polynomial su(1, 1) algebras for the physical systems with the first and second Pöschl-Teller (PT) potentials are constructed, and their specific representations are presented. Meanwhile, these polynomial su(1, 1) algebras are used as an algebraic technique to solve eigenvalues and eigenfunctions of the Hamiltonians associated with the first and second PT potentials. The algebraic approach explores an appropriate new pair of raising and lowing operators K-circumflex{sub ±} of polynomial su(1, 1) algebra as a pair of shift operators of our Hamiltonians. In addition, two usual su(1, 1) algebras associated with the first and second PT potentials are derivedmore » naturally from the polynomial su(1, 1) algebras built by us.« less

Interplay of quasiparticle-vibration coupling and pairing correlations on β-decay half-lives

NASA Astrophysics Data System (ADS)

Niu, Y. F.; Niu, Z. M.; Colò, G.; Vigezzi, E.

2018-05-01

The nuclear β-decay half-lives of Ni and Sn isotopes, around the closed shell nuclei 78Ni and 132Sn, are investigated by computing the distribution of the Gamow-Teller strength using the Quasiparticle Random Phase Approximation (QRPA) with quasiparticle-vibration coupling (QPVC), based on ground-state properties obtained by Hartree-Fock-Bogoliubov (HFB) calculations. We employ the effective interaction SkM* and a zero-range effective pairing force. The half-lives are strongly reduced by including the QPVC. We study in detail the effects of isovector (IV) and isoscalar (IS) pairing. Increasing the IV strength tends to increase the lifetime for nuclei in the proximity of, but lighter than, the closed-shell ones in QRPA calculations, while the effect is significantly reduced by taking into account the QPVC. On the contrary, the IS pairing mainly plays a role for nuclei after the shell closure. Increasing its strength decreases the half-lives, and the effect at QRPA and QRPA+QPVC level is comparable. The effect of IS pairing is particularly pronounced in the case of the Sn isotopes, where it turns out to be instrumental to obtain good agreement with experimental data.

The Jahn-Teller distortion influenced ferromagnetic order in Pr1-xLaxMnO3

NASA Astrophysics Data System (ADS)

He, Feifei; Mao, Zhongquan; Tang, Lingyun; Zhang, Jiang; Chen, Xi

2018-06-01

The structural and magnetic properties of Pr1-xLaxMnO3 (0 ≤ x ≤ 1) polycrystalline powders are investigated. A structural phase transition from a large Jahn-Teller (J-T) distorted orthorhombic structure to a small J-T distorted orthorhombic phase is found at x = 0.70, while the LaMnO3 is showed to have a rhombohedral structure. All the samples exhibit ferromagnetic ordering, and meanwhile, a reentrant spin glass behavior at low temperature. The relationship between J-T distortions and the ferromagnetic order is discussed.

The decay widths, the decay constants, and the branching fractions of a resonant state

NASA Astrophysics Data System (ADS)

de la Madrid, Rafael

2015-08-01

We introduce the differential and the total decay widths of a resonant (Gamow) state decaying into a continuum of stable states. When the resonance has several decay modes, we introduce the corresponding partial decay widths and branching fractions. In the approximation that the resonance is sharp, the expressions for the differential, partial and total decay widths of a resonant state bear a close resemblance with the Golden Rule. In such approximation, the branching fractions of a resonant state are the same as the standard branching fractions obtained by way of the Golden Rule. We also introduce dimensionless decay constants along with their associated differential decay constants, and we express experimentally measurable quantities such as the branching fractions and the energy distributions of decay events in terms of those dimensionless decay constants.

Neutron-$$\\gamma$$ competition for β-delayed neutron emission

DOE PAGES

Mumpower, Matthew Ryan; Kawano, Toshihiko; Moller, Peter

2016-12-19

Here we present a coupled quasiparticle random phase approximation and Hauser-Feshbach (QRPA+HF) model for calculating delayed particle emission. This approach uses microscopic nuclear structure information, which starts with Gamow-Teller strength distributions in the daughter nucleus and then follows the statistical decay until the initial available excitation energy is exhausted. Explicitly included at each particle emission stage is γ-ray competition. We explore this model in the context of neutron emission of neutron-rich nuclei and find that neutron-γ competition can lead to both increases and decreases in neutron emission probabilities, depending on the system considered. Finally, a second consequence of this formalismmore » is a prediction of more neutrons on average being emitted after β decay for nuclei near the neutron drip line compared to models that do not consider the statistical decay.« less

Isospin-symmetry-breaking effects in A˜70 nuclei within beyond-mean-field approach

NASA Astrophysics Data System (ADS)

Petrovici, A.; Andrei, O.

2015-02-01

Particular isospin-symmetry-breaking probes including Coulomb energy differences (CED), mirror energy differences (MED), and triplet energy differences (TED) manifest anomalies in the A˜70 isovector triplets of nuclei. The structure of proton-rich nuclei in the A˜70 mass region suggests shape coexistence and competition between pairing correlations in different channels. Recent results concerning the interplay between isospin-mixing and shape-coexistence effects on exotic phenomena in A˜70 nuclei obtained within the beyond-mean-field complex Excited Vampir variational model with symmetry projection before variation using a realistic effective interaction in a relatively large model space are presented. Excited Vampir predictions concerning the Gamow-Teller β decay to the odd-odd N=Z 66As and 70Br nuclei correlated with the pair structure analysis in the T=1 and T=0 channel of the involved wave functions are discussed.

A study of the Fermi (0+) transition in {sup 14}C(p,n){sup 14}N at 495 MeV

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, D.A.; Delucia, S.L.; Luther, B.A.

1995-10-01

Differential cross sections and analyzing powers have been measured for the {sup 14}C(p,n) {sup 14}N (IAS) reaction with a proton energy of 495 MeV and an angular distribution of 0{sub lab} = 0{degrees} to 10{degrees} (q = 0.0 to 0.956 fm{sup -1}) at the LAMPF Neutron Time-of-Flight Facility (NTOF). Previous A, results for targets with mixed Fermi and Gamow-Teller (AJ{close_quote} = 0+ and 1+) transitions are not well re-produced with either DWIA of RIA calculations. The {open_quotes}C target offers the best opportunity to study a Fermi transition (2.31 MeV) separated from the nearest GT strength (3.95 MeV). The results comparemore » favorably with calculations. These will be presented, and the implications for mixed transitions will be discussed.« less

Thermal and composition driven phase transition in the co-operative Jahn-Teller distorted Zn1-xCuxCr2O4 spinel

NASA Astrophysics Data System (ADS)

Saraswathy, S.; Kalavathi, S.; Rajamadhavan, R.; Asuvathraman, R.

2018-04-01

Phase pure poly crystalline powder samples of spinel compounds with formula Zn1-xCuxCr2O4 have been synthesized. It is found that for a critical concentration of Cu with x=0.58 cubic structure of the parent ZnCr2O4 transforms into a tetragonal structure. The well-known co-operative Jahn-Teller effect induces the structural transition and the observed variation of lattice parameters as a function of Cu substitution displays the role of strain. Thermally driven destruction of the co-operative Jahn-Teller effect and the resultant reverting back to cubic structure is observed to complete at 850 K and 373 K in pristine CuCr2O4 and Zn0.4Cu0.6Cr2O4. A first order transition observed for Zn0.4Cu0.6Cr2O4 is at variance with the continuous transition observed in the literature for Mg0.46Cu0.54Cr2O4.

Analysis of the workload of bank tellers of a Brazilian public institution.

PubMed

Serikawa, Simoni S; Albieri, Ana Carolina S; Bonugli, Gustavo P; Greghi, Marina F

2012-01-01

During the last decades there have been many changes in the banking sector organization. It has been also observed the mutual growing of musculoskeletal and mental disorders. This study investigated the workload of bank tellers at a Brazilian public institution. It was performed the Ergonomic Work Analysis (EWA). Three employees participated in this study. During the analysis process, three research instruments were applied: Inventory of Work and Risk of Illness, Yoshitake Fatigue Questionnaire and Nordic Musculoskeletal Questionnaire, beyond the realization of footage recordings and the self-confrontation. The results indicated the existence of an excess of workload on the evaluated workstations, mainly in relation to mental order constraints, that overlaps the physical aspects. Thereby it was found that the employees tend to adopt strategies trying to reduce the impacts of the excess of workload, in order to regulate it.

Low-lying intruder and tensor-driven structures in 82As revealed by β decay at a new movable-tape-based experimental setup

NASA Astrophysics Data System (ADS)

Etilé, A.; Verney, D.; Arsenyev, N. N.; Bettane, J.; Borzov, I. N.; Cheikh Mhamed, M.; Cuong, P. V.; Delafosse, C.; Didierjean, F.; Gaulard, C.; Van Giai, Nguyen; Goasduff, A.; Ibrahim, F.; Kolos, K.; Lau, C.; Niikura, M.; Roccia, S.; Severyukhin, A. P.; Testov, D.; Tusseau-Nenez, S.; Voronov, V. V.

2015-06-01

The β decay of 82Ge Ge was re-investigated using the newly commissioned tape station BEDO at the electron-driven ISOL (isotope separation on line) facility ALTO operated by the Institut de Physique Nucléaire, Orsay. The original motivation of this work was focused on the sudden occurrence in the light N =49 odd-odd isotonic chain of a large number of J ≤1 states (positive or negative parity) in 80Ga by providing a reliable intermediate example, viz., 82As. The extension of the 82As level scheme towards higher energies from the present work has revealed three potential 1+ states above the already known one at 1092 keV. In addition our data allow ruling out the hypothesis that the 843 keV level could be a 1+ state. A detailed analysis of the level scheme using both an empirical core-particle coupling model and a fully microscopic treatment within a Skyrme-QRPA (quasiparticle random-phase approximation) approach using the finite-rank separable approximation was performed. From this analysis two conclusions can be drawn: (i) the presence of a large number of low-lying low-spin negative parity states is due to intruder states stemming from above the N =50 shell closure, and (ii) the sudden increase, from 82As to 80Ga, of the number of low-lying 1+ states and the corresponding Gamow-Teller fragmentation are naturally reproduced by the inclusion of tensor correlations and couplings to 2p-2h excitations.

β -delayed γ decay of P 26 : Possible evidence of a proton halo

DOE PAGES

Pérez-Loureiro, D.; Wrede, C.; Bennett, M. B.; ...

2016-06-01

Background: Measurements of β decay provide important nuclear structure information that can be used to probe isospin asymmetries and inform nuclear astrophysics studies. Purpose: To measure the β-delayed γ decay of 26P and compare the results with previous experimental results and shell-model calculations. Method: A 26P fast beam produced using nuclear fragmentation was implanted into a planar germanium detector. Its β-delayed γ-ray emission was measured with an array of 16 high-purity germanium detectors. Positrons emitted in the decay were detected in coincidence to reduce the background. Results: The absolute intensities of 26P β-delayed γ-rays were determined. A total of sixmore » new β-decay branches and 15 new γ-ray lines have been observed for the first time in 26P β-decay. A complete β-decay scheme was built for the allowed transitions to bound excited states of 26Si. ft values and Gamow-Teller strengths were also determined for these transitions and compared with shell model calculations and the mirror β-decay of 26Na, revealing significant mirror asymmetries. Conclusions: A very good agreement with theoretical predictions based on the USDB shell model is observed. The significant mirror asymmetry observed for the transition to the first excited state (δ=51(10)%) may be evidence for a proton halo in 26P.« less

Double-β decay within a consistent deformed approach

NASA Astrophysics Data System (ADS)

Delion, D. S.; Suhonen, J.

2015-05-01

In this paper we present a timely application of the proton-neutron deformed quasiparticle random-phase approximation (p n -dQRPA), designed to describe in a consistent way the 1+ Gamow-Teller states in odd-odd deformed nuclei. For this purpose we apply a projection before variation procedure by using a single-particle basis with projected angular momentum, provided by the diagonalization of a spherical mean field plus quadrupole-quadrupole interaction. The residual Hamiltonian contains pairing plus proton-neutron dipole terms in particle-hole and particle-particle channels, with constant strengths. As an example we describe the two-neutrino double-beta (2 ν β β ) decay of 150Nd to the ground state of 150Sm. The experimental (p ,n ) type of strength in 150Nd and the (n ,p ) type of strength in 150Sm are reasonably reproduced and the 2 ν β β decay matrix element depicts a strong dependence upon the particle-particle strength gp p. The experimental half-life is reproduced for gp p=0.05 . It turns out that the measured half-lives for 2 ν β β transitions between other deformed superfluid partners with mass numbers A =82 ,96,100,128,130,238 are reproduced with fairly good accuracy by using this value of gp p.

Pseudo Jahn-Teller coupling in trioxides XO3(0,1,-1) with 22 and 23 valence electrons

NASA Astrophysics Data System (ADS)

Grein, Friedrich

2013-05-01

D3h and C2v geometries and energies, vertical excitation energies, as well as minimal energy paths as function of the O1(z)-X-O2 angle α were obtained for XO3(0,1,-1) (X = B, Al, Ga; C, Si, Ge; N, P, As; S, Se) molecules and ions with 22 and 23 valence electrons (VE), using density functional theory (DFT), coupled cluster with single and double substitutions with noniterative triple excitations (CCSD(T)), equation of motion (EOM)-CCSD, time-dependent DFT, and multi-reference configuration interaction methods. It is shown that pseudo Jahn-Teller (PJT) coupling increases as the central atom X becomes heavier, due to decreases in excitation energies. As is well known for CO3, the excited 1E' states of the 22 VE systems SiO3, GeO3; NO_3 ^ +, PO3+, AsO3+; BO3-, AlO3-, GaO3- have strong vibronic coupling with the 1A1' ground state via the e' vibrational modes, leading to a C2v minimum around α = 145°. For first and second row X atoms, there is an additional D3h minimum (α = 120°). Interacting excited states have minima around 135°. In the 23 VE systems CO3-, SiO3-; NO3, PO3; SO3+, coupling of the excited 2E' with the 2A2' ground state via the e' mode does not generate a C2v state. Minima of interacting excited states are close to 120°. However, due to very strong PJT coupling, a double-well potential is predicted for GeO3-, AsO3, and SeO3+, with a saddle point at D3h symmetry. Interaction of the b2 highest occupied molecular orbital with the b2 lowest unoccupied molecular orbital, both oxygen lone pair molecular orbitals, is seen as the reason for the C2v stabilization of 22 VE molecules.

Nodeless vibrational amplitudes and quantum nonadiabatic dynamics in the nested funnel for a pseudo Jahn-Teller molecule or homodimer

NASA Astrophysics Data System (ADS)

Peters, William K.; Tiwari, Vivek; Jonas, David M.

2017-11-01

The nonadiabatic states and dynamics are investigated for a linear vibronic coupling Hamiltonian with a static electronic splitting and weak off-diagonal Jahn-Teller coupling through a single vibration with a vibrational-electronic resonance. With a transformation of the electronic basis, this Hamiltonian is also applicable to the anti-correlated vibration in a symmetric homodimer with marginally strong constant off-diagonal coupling, where the non-adiabatic states and dynamics model electronic excitation energy transfer or self-exchange electron transfer. For parameters modeling a free-base naphthalocyanine, the nonadiabatic couplings are deeply quantum mechanical and depend on wavepacket width; scalar couplings are as important as the derivative couplings that are usually interpreted to depend on vibrational velocity in semiclassical curve crossing or surface hopping theories. A colored visualization scheme that fully characterizes the non-adiabatic states using the exact factorization is developed. The nonadiabatic states in this nested funnel have nodeless vibrational factors with strongly avoided zeroes in their vibrational probability densities. Vibronic dynamics are visualized through the vibrational coordinate dependent density of the time-dependent dipole moment in free induction decay. Vibrational motion is amplified by the nonadiabatic couplings, with asymmetric and anisotropic motions that depend upon the excitation polarization in the molecular frame and can be reversed by a change in polarization. This generates a vibrational quantum beat anisotropy in excess of 2/5. The amplitude of vibrational motion can be larger than that on the uncoupled potentials, and the electronic population transfer is maximized within one vibrational period. Most of these dynamics are missed by the adiabatic approximation, and some electronic and vibrational motions are completely suppressed by the Condon approximation of a coordinate-independent transition dipole between

Nodeless vibrational amplitudes and quantum nonadiabatic dynamics in the nested funnel for a pseudo Jahn-Teller molecule or homodimer.

PubMed

Peters, William K; Tiwari, Vivek; Jonas, David M

2017-11-21

The nonadiabatic states and dynamics are investigated for a linear vibronic coupling Hamiltonian with a static electronic splitting and weak off-diagonal Jahn-Teller coupling through a single vibration with a vibrational-electronic resonance. With a transformation of the electronic basis, this Hamiltonian is also applicable to the anti-correlated vibration in a symmetric homodimer with marginally strong constant off-diagonal coupling, where the non-adiabatic states and dynamics model electronic excitation energy transfer or self-exchange electron transfer. For parameters modeling a free-base naphthalocyanine, the nonadiabatic couplings are deeply quantum mechanical and depend on wavepacket width; scalar couplings are as important as the derivative couplings that are usually interpreted to depend on vibrational velocity in semiclassical curve crossing or surface hopping theories. A colored visualization scheme that fully characterizes the non-adiabatic states using the exact factorization is developed. The nonadiabatic states in this nested funnel have nodeless vibrational factors with strongly avoided zeroes in their vibrational probability densities. Vibronic dynamics are visualized through the vibrational coordinate dependent density of the time-dependent dipole moment in free induction decay. Vibrational motion is amplified by the nonadiabatic couplings, with asymmetric and anisotropic motions that depend upon the excitation polarization in the molecular frame and can be reversed by a change in polarization. This generates a vibrational quantum beat anisotropy in excess of 2/5. The amplitude of vibrational motion can be larger than that on the uncoupled potentials, and the electronic population transfer is maximized within one vibrational period. Most of these dynamics are missed by the adiabatic approximation, and some electronic and vibrational motions are completely suppressed by the Condon approximation of a coordinate-independent transition dipole between

Jet-resolved vibronic structure in the higher excited states of N2O - Ultraviolet three-photon absorption spectroscopy from 80,000 to 90,000/cm

NASA Technical Reports Server (NTRS)

Patsilinakou, E.; Wiedmann, R. T.; Fotakis, C.; Grant, E. R.

1989-01-01

Ionization-detected UV multiphoton absorption spectroscopy of the excited states of N2O is presented, showing Rydberg structure within 20,000/cm of the first ionization threshold. Despite evidence for strong Rydberg-continuum coupling in the form of broadened bands and Fano line-shapes, the Rydberg structure persists, with atomic-like quantum defects and vibration structure well-matched with that of the ion. In the most clearly resolved spectrum, corresponding to the 3p(delta)1Pi state, Renner-Teller and Herzberg-Teller coupling of electronic and vibrational angular momentum are revealed. It is suggested that these mixings are properties of the N2O(+)Pi ion core.

Studying Electron-Capture on ^64Zn in Supernovae with the (t,^3He) Charge-Exchange Reaction

NASA Astrophysics Data System (ADS)

Hitt, G. W.; Austin, Sam M.; Bazin, D.; Gade, A.; Guess, C. J.; Galaviz-Redondo, D.; Shimbara, Y.; Tur, C.; Zegers, R. G. T.; Horoi, M.; Howard, M. E.; Smith, E. E.

2008-10-01

A secondary, 115 MeV/u triton beam has been developed at NSCL for use in (t,^3He) charge-exchange(CE) reaction studies. This (n,p)-type CE reaction is useful for extracting the full Gamow-Teller (GT) response of the nucleus, overcoming Q-value restrictions present in conventional beta-decay studies. The strength (B(GT)) in ^64Cu has been determined from the absolute cross section measurement of ^64Zn(t,^3He) near zero-degrees, exploiting an empirical proportionality between cross section and B(GT). The detailed features of the B(GT) distribution in a nucleus has an important impact on electron-capture (EC) rates in Type Ia and Core-Collapse supernovae. The measured B(GT) in ^64Cu is directly compared with the results of modern shell model interactions which are used to calculate the GT contribution to EC on nuclei in supernova simulations.

Isospin-symmetry-breaking effects in A∼70 nuclei within beyond-mean-field approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petrovici, A.; Andrei, O.

2015-02-24

Particular isospin-symmetry-breaking probes including Coulomb energy differences (CED), mirror energy differences (MED), and triplet energy differences (TED) manifest anomalies in the A∼70 isovector triplets of nuclei. The structure of proton-rich nuclei in the A∼70 mass region suggests shape coexistence and competition between pairing correlations in different channels. Recent results concerning the interplay between isospin-mixing and shape-coexistence effects on exotic phenomena in A∼70 nuclei obtained within the beyond-mean-field complex Excited Vampir variational model with symmetry projection before variation using a realistic effective interaction in a relatively large model space are presented. Excited Vampir predictions concerning the Gamow-Teller β decay to themore » odd-odd N=Z {sup 66}As and {sup 70}Br nuclei correlated with the pair structure analysis in the T=1 and T=0 channel of the involved wave functions are discussed.« less

Nuclear spin-isospin excitations from covariant quasiparticle-vibration coupling

NASA Astrophysics Data System (ADS)

Robin, Caroline; Litvinova, Elena

2016-09-01

Methods based on the relativistic Lagrangian of quantum hadrodynamics and nuclear field theory provide a consistent framework for the description of nuclear excitations, naturally connecting the high- and medium-energy scales of mesons to the low-energy domain of nucleonic collective motion. Applied in the neutral channel, this approach has been quite successful in describing the overall transition strength up to high excitation energies, as well as fine details of the low-lying distribution. Recently, this method has been extended to the description of spin-isospin excitations in open-shell nuclei. In the charge-exchange channel, the coupling between nucleons and collective vibrations generates a time-dependent proton-neutron effective interaction, in addition to the static pion and rho-meson exchange, and introduces complex configurations that induce fragmentation and spreading of the resonances. Such effects have a great impact on the quenching of the strength and on the computing of weak reaction rates that are needed for astrophysics modeling. Gamow-Teller transitions in medium-mass nuclei and associated beta-decay half-lives will be presented. Further developments aiming to include additional ground-state correlations will also be discussed. This work is supported by US-NSF Grants PHY-1404343 and PHY-1204486.

IMPACT OF NEW GAMOW–TELLER STRENGTHS ON EXPLOSIVE TYPE IA SUPERNOVA NUCLEOSYNTHESIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mori, Kanji; Famiano, Michael A.; Kajino, Toshitaka

2016-12-20

Recent experimental results have confirmed a possible reduction in the Gamow–Teller (GT{sub +}) strengths of pf-shell nuclei. These proton-rich nuclei are of relevance in the deflagration and explosive burning phases of SNe Ia. While prior GT strengths result in nucleosynthesis predictions with a lower-than-expected electron fraction, a reduction in the GT{sub +} strength can result in a slightly increased electron fraction compared to previous shell model predictions, though the enhancement is not as large as previous enhancements in going from rates computed by Fuller, Fowler, and Newman based on an independent particle model. A shell model parametrization has been developed thatmore » more closely matches experimental GT strengths. The resultant electron-capture rates are used in nucleosynthesis calculations for carbon deflagration and explosion phases of SNe Ia, and the final mass fractions are compared to those obtained using more commonly used rates.« less

The Renner-Teller effect in HCCCl(+)(X̃(2)Π) studied by zero-kinetic energy photoelectron spectroscopy and ab initio calculations.

PubMed

Sun, Wei; Dai, Zuyang; Wang, Jia; Mo, Yuxiang

2015-05-21

The spin-vibronic energy levels of the chloroacetylene cation up to 4000 cm(-1) above the ground state have been measured using the one-photon zero-kinetic energy photoelectron spectroscopic method. The spin-vibronic energy levels have also been calculated using a diabatic model, in which the potential energy surfaces are expressed by expansions of internal coordinates, and the Hamiltonian matrix equation is solved using a variational method with harmonic basis functions. The calculated spin-vibronic energy levels are in good agreement with the experimental data. The Renner-Teller (RT) parameters describing the vibronic coupling for the H-C≡C bending mode (ε4), Cl-C≡C bending mode (ε5), the cross-mode vibronic coupling (ε45) of the two bending vibrations, and their vibrational frequencies (ω4 and ω5) have also been determined using an effective Hamiltonian matrix treatment. In comparison with the spin-orbit interaction, the RT effect in the H-C≡C bending (ε4) mode is strong, while the RT effect in the Cl-C≡C bending mode is weak. There is a strong cross-mode vibronic coupling of the two bending vibrations, which may be due to a vibronic resonance between the two bending vibrations. The spin-orbit energy splitting of the ground state has been determined for the first time and is found to be 209 ± 2 cm(-1).

Bethe, Oppenheimer, Teller and the Fermi Award: Norris Bradbury Speaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meade, Roger Allen

In 1956 the Enrico Fermi Presidential Award was established to recognize scientists, engineers, and science policymakers who gave unstintingly over their careers to advance energy science and technology. The first recipient was John von Neumann. .1 Among those scientists who were thought eligible for the award were Hans Bethe, J. Robert Oppenheimer, and Edward Teller. In 1959 Norris Bradbury was asked to comment on the relative merits of each these three men, whom he knew well from their affiliation with Los Alamos. Below is a reproduction of the letter Bradbury sent to Dr. Warren C. Johnson of the AEC’s Generalmore » Advisory Committee(GAC) containing his evaluation of each man. The letter might surprise those not accustomed to Bradbury’s modus operandi of providing very detailed and forthright answers to the AEC. The letter, itself, was found in cache of old microfilm. Whether because of the age of the microfilm or the quality of the filming process, portions of the letter are not legible. Where empty brackets appear, the word or words could not be read or deduced. Words appearing in brackets are guesses that appear, from the image, to be what was written. These guesses, of course, are just that – guesses.« less

Is talking to an automated teller machine natural and fun?

PubMed

Chan, F Y; Khalid, H M

Usability and affective issues of using automatic speech recognition technology to interact with an automated teller machine (ATM) are investigated in two experiments. The first uncovered dialogue patterns of ATM users for the purpose of designing the user interface for a simulated speech ATM system. Applying the Wizard-of-Oz methodology, multiple mapping and word spotting techniques, the speech driven ATM accommodates bilingual users of Bahasa Melayu and English. The second experiment evaluates the usability of a hybrid speech ATM, comparing it with a simulated manual ATM. The aim is to investigate how natural and fun can talking to a speech ATM be for these first-time users. Subjects performed the withdrawal and balance enquiry tasks. The ANOVA was performed on the usability and affective data. The results showed significant differences between systems in the ability to complete the tasks as well as in transaction errors. Performance was measured on the time taken by subjects to complete the task and the number of speech recognition errors that occurred. On the basis of user emotions, it can be said that the hybrid speech system enabled pleasurable interaction. Despite the limitations of speech recognition technology, users are set to talk to the ATM when it becomes available for public use.

Beta-decay rates of FP shell nuclei with A greater than 60 in massive stars at the presupernova stage

NASA Astrophysics Data System (ADS)

Kar, K.; Ray, A.; Sarkar, S.

1994-10-01

Beta decay and electron capture on a number of neutron-rich nuclei with A greater than 60 at the presupernova stage may play an important role in determining the hydrostatic core structure of massive presupernova stars and, through this, affect the subsequent evolution during the gravitational collapse and supernova explosion phases. In particular, some isotopes of cobalt and copper can make a substantial contribution to the overall changes in the lepton fraction and entropy of the stellar core during its very late stage of evolution. In the stellar evolution calculations to date, many of these nuclei could not be appropriately tracked in the reaction network, since reliable rates for these have not been available so far. We describe a model to calculate the beta-decay rates using an average beta strength function and an electron phase-space factor evaluated for typical presupernova matter density (rho = 3 x 107-3 x 109 g/cu cm) and temperature (T = (2-5) x 109 K). For the Gamnow-Teller (GT) strength function we use a sum rule calculated by the spectral distribution theory, and the centroid of the distribution is obtained from experimental data on (p, n) reactions. The width sigma of the GT strength function has two parts (sigma2 = (sigmaN exp 2 + (sigmaC exp 2, with sigmaC = 0.157ZA-1/3). The parameter sigmaN is fixed by a best fit to the observed half-lives for the free decays of a number of A greater than 60 nuclei. In the calculation of rates we include contributions from the excited states of the mother nucleus wherever they are known experimentally. For the excited states one uses the same form of the GT strength function, but shifted in energy using the extended isobaric analog state argument. The method is particularly suited for calculating contributions from the excited states important at high temperatures relevant at the presupernova stellar evolution phase. We also include the contributions to the transition rates from the Gamow-Teller resonance states

A robust and effective time-independent route to the calculation of Resonance Raman spectra of large molecules in condensed phases with the inclusion of Duschinsky, Herzberg-Teller, anharmonic, and environmental effects

PubMed Central

Egidi, Franco; Bloino, Julien; Cappelli, Chiara; Barone, Vincenzo

2015-01-01

We present an effective time-independent implementation to model vibrational resonance Raman (RR) spectra of medium-large molecular systems with the inclusion of Franck-Condon (FC) and Herzberg-Teller (HT) effects and a full account of the possible differences between the harmonic potential energy surfaces of the ground and resonant electronic states. Thanks to a number of algorithmic improvements and very effective parallelization, the full computations of fundamentals, overtones, and combination bands can be routinely performed for large systems possibly involving more than two electronic states. In order to improve the accuracy of the results, an effective inclusion of the leading anharmonic effects is also possible, together with environmental contributions under different solvation regimes. Reduced-dimensionality approaches can further enlarge the range of applications of this new tool. Applications to imidazole, pyrene, and chlorophyll a1 in solution are reported, as well as comparisons with available experimental data. PMID:26550003

Limits on tensor coupling from neutron β decay

NASA Astrophysics Data System (ADS)

Pattie, R. W., Jr.; Hickerson, K. P.; Young, A. R.

2013-10-01

Limits on the tensor couplings generating a Fierz interference term b in mixed Gamow-Teller Fermi decays can be derived by combining data from measurements of angular correlation parameters in neutron decay, the neutron lifetime, and GV=GFVud as extracted from measurements of the Ft values from the 0+→0+ superallowed decay data set. These limits are derived by comparing the neutron β-decay rate as predicted in the standard model with the measured decay rate while allowing for the existence of beyond the standard model (BSM) couplings. We analyze limits derived from the electron-neutrino asymmetry a, or the beta asymmetry A, finding that the most stringent limits for CT/CA under the assumption of no right-handed neutrinos is -0.0026

Muon, photon and nuclear CERs for ββ - ν response studies

NASA Astrophysics Data System (ADS)

Ejiri, H.

2015-10-01

Neutrino nuclear responses for neutrino-less double beta decays (0νββ DBD) are studied by muon, photon and nuclear charge exchange reactions (CER) and β-EC transitions. These experimental responses with low and medium momentum transfers are used to evaluate 0νββ nuclear matrix elements and the solar neutrino interactions with atoms and nuclei of DBD detectors. Gamma-ray measurements from residual RI nuclei produced by (µ, νµxn) reactions on 100Mo shows a giant resonance around 12-15 MeV for µ- capture strength. Single β Gamow-Teller (GT) and spin-dipole (SD) strengths are reduced with respect to pnQRPA calculations by gAe f f≈0.5 -0.6 gA , suggesting considerable reductions of the axial vector responses for DBD. Solar neutrino nuclear interactions with nuclei of the DBD isotopes and atoms of liquid scintillators used for DBD experiments are shown to be the serious backgrounds at the ROI (region of interest) of 0νββ.

Using Extended Huckel Theory as a Platform to Introduce Jahn-Teller Distortion: The Spontaneous Distortion of 1,3,5,7-Cyclooctatetraene from a Perfect Octagon

ERIC Educational Resources Information Center

Sohlberg, Karl; Liu, Xiang

2013-01-01

Herein, a slightly enhanced version of extended Huckel molecular orbital theory is applied to demonstrate the spontaneous distortion of 1,3,5,7-cyclooctatetraene from a perfect octagon, a consequence of the Jahn-Teller effect. The exercise is accessible to students who have been introduced to basic quantum mechanics and extended Huckel molecular…

Vibronic eigenstates and the geometric phase effect in the 2E″ state of NO3.

PubMed

Eisfeld, Wolfgang; Viel, Alexandra

2017-01-21

The 2 E″ state of NO 3 , a prototype for the Jahn-Teller effect, has been an enigma and a challenge for a long time for both experiment and theory. We present a detailed theoretical study of the vibronic quantum dynamics in this electronic state, uncovering the effects of tunnelling, geometric phase, and symmetry. To this end, 45 vibronic levels of NO 3 in the 2 E″ state are determined accurately and analyzed thoroughly. The computation is based on a high quality diabatic potential representation of the two-sheeted surface of the 2 E″ state developed by us [W. Eisfeld et al., J. Chem. Phys. 140, 224109 (2014)] and on the multi-configuration time dependent Hartree approach. The vibrational eigenstates of the NO 3 - anion are determined and analyzed as well to gain a deeper understanding of the symmetry properties of such D 3h symmetric systems. To this end, 61 eigenstates of the NO 3 - anion ground state are computed using the single sheeted potential surface of the 1 A 1 state published in the same reference quoted above. The assignments of both the vibrational and vibronic levels are discussed. A simple model is proposed to rationalize the computed NO 3 spectrum strongly influenced by the Jahn-Teller couplings, the associated geometric phase effect, and the tunnelling. Comparison with the available spectroscopic data is also presented.

Simulation Of Wave Function And Probability Density Of Modified Poschl Teller Potential Derived Using Supersymmetric Quantum Mechanics

NASA Astrophysics Data System (ADS)

Angraini, Lily Maysari; Suparmi, Variani, Viska Inda

2010-12-01

SUSY quantum mechanics can be applied to solve Schrodinger equation for high dimensional system that can be reduced into one dimensional system and represented in lowering and raising operators. Lowering and raising operators can be obtained using relationship between original Hamiltonian equation and the (super) potential equation. In this paper SUSY quantum mechanics is used as a method to obtain the wave function and the energy level of the Modified Poschl Teller potential. The graph of wave function equation and probability density is simulated by using Delphi 7.0 programming language. Finally, the expectation value of quantum mechanics operator could be calculated analytically using integral form or probability density graph resulted by the programming.

Electron temperature and de Hoffmann-Teller potential change across the Earth's bow shock: New results from ISEE 1

NASA Astrophysics Data System (ADS)

Hull, A. J.; Scudder, J. D.; Fitzenreiter, R. J.; Ogilvie, K. W.; Newbury, J. A.; Russell, C. T.

We present a survey of the trends between the electron temperature increase ΔTe and the de Hoffmann-Teller frame (HTF) electrostatic potential jump ΔΦHT and their correlation with other parameters that characterize the shock transition using a new ISEE 1 database of 129 Earth bow shock crossings. A fundamental understanding of the HTF potential is central to distinguishing the reversible and irreversible changes to electron temperature across collisionless shocks. The HTF potential is estimated using three different techniques: (1) integrating the steady state, electron fluid momentum equation across the shock layer using high time resolution plasma and field data from ISEE 1, (2) using the steady state, electron fluid energy equation, and (3) using an electron polytrope approximation. We find that ΔΦHT and ΔTe are strongly and positively correlated with |Δ(mpUn2/2)|, which is in good qualitative agreement with earlier experimental surveys [Thomsen et al., 1987b; Schwartz et al., 1988] that used bow shock model normals and used the flow in the spacecraft frame. There is a strong linear organization of the ΔTe with ΔΦHT, which suggests an average effective electron polytropic index of <γe>~2. In addition, ΔTe and ΔΦHT are organized by βe, although our results may be biased by our limited sampling of shock conditions. Comparisons indicate that the differentials in the HTF potential δΦHT are proportional to the differentials in the magnetic field intensity δB across the shock, with a proportionality constant κ that is a fixed constant for a given shock crossing.

An EPR investigation of the dynamic Jahn-Teller effect in SrCl2:y(2 plus) and SrCl2:Sc(2 plus)

NASA Technical Reports Server (NTRS)

Herrington, J. R.; Estle, T. L.; Boatner, L. A.

1972-01-01

EPR spectra have been observed for SrCl2:Y(2+) and SrCl2:Sc(2+) at liquid helium temperatures. At 1.2 K the spectra were dominated by anisotropic hyperfine patterns whose lineshapes and angular dependences were explained using second order solutions of the effective Hamiltonian for an isolated 2Eg state split by large random internal strains. Pronounced asymmetries in some of the strin produced lineshapes for Srcl2:Sc(2+) are shown to result from second order terms in the solution of the effective Hamiltonian. Coexisting with the anisotropic hyperfine patterns are weak nearly isotropic hyperfine patterns with typical lineshapes. Variations in the apparent intensity of lines in these weak hyperfine patterns as functions of the applied magnetic field direction and temperature imply that these lines result from averaging by vibronic relaxation of a portion of the anisotropic pattern. The effective Hamiltonian parameters for SrCl2:La(2+), SrCl2:y(2+), and SrCl2:SC(2+) are analyzed in terms of crystal field theory modified to include a dynamic Jahn-Teller effect.

Ab initio study of dynamical E × e Jahn-Teller and spin-orbit coupling effects in the transition-metal trifluorides TiF3, CrF3, and NiF3

NASA Astrophysics Data System (ADS)

Mondal, Padmabati; Opalka, Daniel; Poluyanov, Leonid V.; Domcke, Wolfgang

2012-02-01

Multiconfiguration ab initio methods have been employed to study the effects of Jahn-Teller (JT) and spin-orbit (SO) coupling in the transition-metal trifluorides TiF3, CrF3, and NiF3, which possess spatially doubly degenerate excited states (ME) of even spin multiplicities (M = 2 or 4). The ground states of TiF3, CrF3, and NiF3 are nondegenerate and exhibit minima of D3h symmetry. Potential-energy surfaces of spatially degenerate excited states have been calculated using the state-averaged complete-active-space self-consistent-field method. SO coupling is described by the matrix elements of the Breit-Pauli operator. Linear and higher order JT coupling constants for the JT-active bending and stretching modes as well as SO-coupling constants have been determined. Vibronic spectra of JT-active excited electronic states have been calculated, using JT Hamiltonians for trigonal systems with inclusion of SO coupling. The effect of higher order (up to sixth order) JT couplings on the vibronic spectra has been investigated for selected electronic states and vibrational modes with particularly strong JT couplings. While the weak SO couplings in TiF3 and CrF3 are almost completely quenched by the strong JT couplings, the stronger SO coupling in NiF3 is only partially quenched by JT coupling.

High-precision branching-ratio measurement for the superallowed β+ emitter 74Rb

NASA Astrophysics Data System (ADS)

Dunlop, R.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Andreoiu, C.; Chagnon-Lessard, S.; Chester, A.; Cross, D. S.; Finlay, P.; Garnsworthy, A. B.; Garrett, P. E.; Glister, J.; Hackman, G.; Hadinia, B.; Leach, K. G.; Rand, E. T.; Starosta, K.; Tardiff, E. R.; Triambak, S.; Williams, S. J.; Wong, J.; Yates, S. W.; Zganjar, E. F.

2013-10-01

A high-precision branching-ratio measurement for the superallowed β+ decay of 74Rb was performed at the TRIUMF Isotope Separator and Accelerator (ISAC) radioactive ion-beam facility. The scintillating electron-positron tagging array (SCEPTAR), composed of 10 thin plastic scintillators, was used to detect the emitted β particles; the 8π spectrometer, an array of 20 Compton-suppressed HPGe detectors, was used for detecting γ rays that were emitted following Gamow-Teller and nonanalog Fermi β+ decays of 74Rb; and the Pentagonal Array of Conversion Electron Spectrometers (PACES), an array of 5 Si(Li) detectors, was employed for measuring β-delayed conversion electrons. Twenty-three excited states were identified in 74Kr following 8.241(4)×108 detected 74Rb β decays. A total of 58 γ-ray and electron transitions were placed in the decay scheme, allowing the superallowed branching ratio to be determined as B0=99.545(31)%. Combined with previous half-life and Q-value measurements, the superallowed branching ratio measured in this work leads to a superallowed ft value of 3082.8(65) s. Comparisons between this superallowed ft value and the world-average-corrected Ft¯ value, as well as the nonanalog Fermi branching ratios determined in this work, provide guidance for theoretical models of the isospin-symmetry-breaking corrections in this mass region.

Excited States of the divacancy in SiC

NASA Astrophysics Data System (ADS)

Bockstedte, Michel; Garratt, Thomas; Ivady, Viktor; Gali, Adam

2014-03-01

The divacancy in SiC - a technologically mature material that fulfills the necessary requirements for hosting defect based quantum computing - is a good candidate for implementing a solid state quantum bit. Its ground state is isovalent to the NV center in diamond as demonstrated by density functional theory (DFT). Furthermore, coherent manipulation of divacancy spins in SiC has been demonstrated. The similarities to NV might indicate that the same inter system crossing (ICS) from the high to the low spin state is responsible for its spin-dependent fluorescent signal. By DFT and a DFT-based multi-reference hamiltonian we analyze the excited state spectrum of the defects. In contrast to the current picture of the spin dynamics of the NV center, we predict that a static Jahn-Teller effect in the first excited triplet states governs an ICS both with the excited and ground state of the divacancy.

The 20Ne(d,p) 21Ne Transfer Reaction in Relation to the s-Process Abundances

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nsangu, C. T.; Laird, A. M.; Parikh, A.

2016-01-01

A study of the Ne-20(d,p)Ne-21 transfer reaction was performed using the Quadrupole Dipole Dipole Dipole (Q3D) magnetic spectrograph in Garching, Germany. The experiment probed excitation energies in Ne-21 ranging from 6.9 MeV to 8.5 MeV. The aim was to investigate the spectroscopic information of Ne-21 within the Gamow window of core helium burning in massive stars. Further information in this region will help reduce the uncertainties on the extrapolation down to Gamow window cross sections of the O-17(alpha,gamma)Ne-21 reaction. In low metallicity stars, this reaction has a direct impact on s-process abundances by determining the fate of O-16 as eithermore » a neutron poison or a neutron absorber. The experiment used a 22-MeV deuteron beam, with intensities varying from 0.5-1 mu A, and an implanted target of Ne-20 of 7 mu g/cm(2) in 40 mu g/cm(2) carbon foils. Sixteen Ne-21 peaks have been identified in the E-x = 6.9-8.5 MeV range, of which only thirteen peaks correspond to known states. Only the previously-known E-x = 7.960 MeV state was observed within the Gamow window.« less

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

PubMed

Dhindhwal, Vikash; Baer, Michael; Sathyamurthy, N

2016-05-19

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

The effect of band Jahn-Teller distortion on the magnetoresistivity of manganites: a model study.

PubMed

Rout, G C; Panda, Saswati; Behera, S N

2011-10-05

We present a model study of magnetoresistance through the interplay of magnetisation, structural distortion and external magnetic field for the manganite systems. The manganite system is described by the Hamiltonian which consists of the s-d type double exchange interaction, Heisenberg spin-spin interaction among the core electrons, and the static and dynamic band Jahn-Teller (JT) interaction in the e(g) band. The relaxation time of the e(g) electron is found from the imaginary part of the Green's function using the total Hamiltonian consisting of the interactions due to the electron and phonon. The calculated resistivity exhibits a peak in the pure JT distorted insulating phase separating the low temperature metallic ferromagnetic phase and the high temperature paramagnetic phase. The resistivity is suppressed with the increase of the external magnetic field. The e(g) electron band splitting and its effect on magnetoresistivity is reported here. © 2011 IOP Publishing Ltd

Hour-Glass Neural Network Based Daily Money Flow Estimation for Automatic Teller Machines

NASA Astrophysics Data System (ADS)

Karungaru, Stephen; Akashi, Takuya; Nakano, Miyoko; Fukumi, Minoru

Monetary transactions using Automated Teller Machines (ATMs) have become a normal part of our daily lives. At ATMs, one can withdraw, send or debit money and even update passbooks among many other possible functions. ATMs are turning the banking sector into a ubiquitous service. However, while the advantages for the ATM users (financial institution customers) are many, the financial institution side faces an uphill task in management and maintaining the cash flow in the ATMs. On one hand, too much money in a rarely used ATM is wasteful, while on the other, insufficient amounts would adversely affect the customers and may result in a lost business opportunity for the financial institution. Therefore, in this paper, we propose a daily cash flow estimation system using neural networks that enables better daily forecasting of the money required at the ATMs. The neural network used in this work is a five layered hour glass shaped structure that achieves fast learning, even for the time series data for which seasonality and trend feature extraction is difficult. Feature extraction is carried out using the Akamatsu Integral and Differential transforms. This work achieves an average estimation accuracy of 92.6%.

Nonequilibrium critical dynamics of the two-dimensional Ashkin-Teller model at the Baxter line

NASA Astrophysics Data System (ADS)

Fernandes, H. A.; da Silva, R.; Caparica, A. A.; de Felício, J. R. Drugowich

2017-04-01

We investigate the short-time universal behavior of the two-dimensional Ashkin-Teller model at the Baxter line by performing time-dependent Monte Carlo simulations. First, as preparatory results, we obtain the critical parameters by searching the optimal power-law decay of the magnetization. Thus, the dynamic critical exponents θm and θp, related to the magnetic and electric order parameters, as well as the persistence exponent θg, are estimated using heat-bath Monte Carlo simulations. In addition, we estimate the dynamic exponent z and the static critical exponents β and ν for both order parameters. We propose a refined method to estimate the static exponents that considers two different averages: one that combines an internal average using several seeds with another, which is taken over temporal variations in the power laws. Moreover, we also performed the bootstrapping method for a complementary analysis. Our results show that the ratio β /ν exhibits universal behavior along the critical line corroborating the conjecture for both magnetization and polarization.

Search for excited states in 25O

NASA Astrophysics Data System (ADS)

Jones, M. D.; Fossez, K.; Baumann, T.; DeYoung, P. A.; Finck, J. E.; Frank, N.; Kuchera, A. N.; Michel, N.; Nazarewicz, W.; Rotureau, J.; Smith, J. K.; Stephenson, S. L.; Stiefel, K.; Thoennessen, M.; Zegers, R. G. T.

2017-11-01

Background: Theoretical calculations suggest the presence of low-lying excited states in 25O. Previous experimental searches by means of proton knockout on 26F produced no evidence for such excitations. Purpose: We search for excited states in 25O using the 24O(d ,p ) 25O reaction. The theoretical analysis of excited states in unbound O,2725 is based on the configuration interaction approach that accounts for couplings to the scattering continuum. Method: We use invariant-mass spectroscopy to measure neutron-unbound states in 25O. For the theoretical approach, we use the complex-energy Gamow Shell Model and Density Matrix Renormalization Group method with a finite-range two-body interaction optimized to the bound states and resonances of O-2623, assuming a core of 22O. We predict energies, decay widths, and asymptotic normalization coefficients. Results: Our calculations in a large s p d f space predict several low-lying excited states in 25O of positive and negative parity, and we obtain an experimental limit on the relative cross section of a possible Jπ=1/2 + state with respect to the ground state of 25O at σ1 /2 +/σg .s .=0 .25-0.25+1.0 . We also discuss how the observation of negative parity states in 25O could guide the search for the low-lying negative parity states in 27O. Conclusion: Previous experiments based on the proton knockout of 26F suffered from the low cross sections for the population of excited states in 25O because of low spectroscopic factors. In this respect, neutron transfer reactions carry more promise.

Vibronic Analysis for widetilde{B} - widetilde{X} Transition of Isopropoxy Radical

NASA Astrophysics Data System (ADS)

Chhantyal-Pun, Rabi; Miller, Terry A.

2013-06-01

Alkoxy radicals are important intermediates in combustion and atmospheric chemistry. Alkoxy radicals are also of significant spectroscopic interest for the study of Jahn Teller and pseudo Jahn Teller effects, involving the widetilde{X} and widetilde{A} states. The Jahn Teller effect has been studied in methoxy. Substitution of one or two hydrogens by methyl groups transforms the interaction to a pseudo Jahn Teller effect in ethoxy and isopropoxy. Previously, moderate resolution scans have been obtained for widetilde{B} - widetilde{X} and widetilde{B} - widetilde{A} transition systems, the latter observable at higher temperature. These measurements have shown that the widetilde{X} and widetilde{A} states of isopropoxy are separated by only 60.7(7) cm^{-1} which indicates a strong pseudo Jahn Teller effect in the widetilde{X} state. Such pseduo Jahn Teller coupling should also introduce additional bands into the widetilde{B} - widetilde{X} spectrum and a number of weaker transitions have been observed which may be caused by such effects. In this talk we present a vibronic analysis for the widetilde{B} - widetilde{X} transition based on the experimental results and also the results from recent quantum chemistry calculations.

Acoustic Properties of Crystals with Jahn-Teller Impurities: Elastic Moduli and Relaxation Time. Application to SrF2:Cr2+

NASA Astrophysics Data System (ADS)

Averkiev, Nikita S.; Bersuker, Isaac B.; Gudkov, Vladimir V.; Zhevstovskikh, Irina V.; Sarychev, Maksim N.; Zherlitsyn, Sergei; Yasin, Shadi; Shakurov, Gilman S.; Ulanov, Vladimir A.; Surikov, Vladimir T.

2017-11-01

A new approach to evaluate the relaxation contribution to the total elastic moduli for crystals with Jahn-Teller (JT) impurities is worked out and applied to the analysis of the experimentally measured ultrasound velocity and attenuation in SrF2:Cr2+. Distinguished from previous work, the background adiabatic contribution to the moduli, important for revealing the impurity relaxation contribution, is taken into account. The temperature dependence of the relaxation time for transitions between the equivalent configurations of the JT centers has been obtained, and the activation energy for the latter in SrF2:Cr2+, as well as the linear vibronic coupling constant have been evaluated.

Ba 3 (Cr 0.97(1) Te 0.03(1) ) 2 TeO 9 : in Search of Jahn–Teller Distorted Cr(II) Oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Man-Rong; Deng, Zheng; Lapidus, Saul H.

2016-10-17

A novel 6H - type hexagonal perovskite Ba 3 (Cr 0.97(1) Te 0.03 (1 ) ) 2 TeO 9 was prepared at high pressure (6 GPa) and temperature ( 1 773 K). Both transmission electron microscopy and synchrotron powder x - ray diffraction data demonstrate that Ba 3 (Cr 0.97(1) Te 0.03(1) ) 2 TeO 9 crystallize s in P6 3 / mmc with face - shared (Cr 0.97(1) Te 0.03(1) )O 6 octahedral pairs interconnected with TeO 6 octahedra via corner - sharing. Structure analysis shows a mixed Cr 2+ /Cr 3+ valence state with ~ 10% Cr 2+more » . The existence of Cr 2+ in Ba 3 (Cr 2+ 0.10(1) Cr 3+ 0.87(1) Te 6+ 0.03 ) 2 TeO 9 is further evidenced by x - ray absorption near edge spectr oscopy . Magnetic properties measurements show a paramagnetic response down to 4 K and a small glassy - state curvature at low temperature. In this work, the o ctahedral Cr 2+ O 6 component is stabilized in an oxide material for the first time ; the expected Jahn - Teller distortion of high - spin ( d 4 ) Cr 2+ is not found , which is attributed to the small proportion of Cr 2+ (~ 10%) and the face - sharing arrangement of CrO 6 octahedral pairs, that structu rally dis favor axial distortion.« less

New calculations of gross β-decay properties for astrophysical applications: Speeding-up the classical r process

NASA Astrophysics Data System (ADS)

Möller, Peter; Pfeiffer, Bernd; Kratz, Karl-Ludwig

2003-05-01

Recent compilations of experimental gross β-decay properties, i.e., half-lives (T1/2) and neutron-emission probabilities (Pn), are compared to improved global macroscopic-microscopic model predictions. The model combines calculations within the quasiparticle (QP) random-phase approximation for the Gamow-Teller (GT) part with an empirical spreading of the QP strength and the gross theory for the first-forbidden part of β- decay. Nuclear masses are either taken from the 1995 data compilation of Audi et al., when available, otherwise from the finite-range droplet model. Especially for spherical and neutron-(sub-)magic isotopes a considerable improvement compared to our earlier predictions for pure GT decay (ADNDT, 1997) is observed. T1/2 and Pn values up to the neutron drip line have been used in r-process calculations within the classical “waiting-point” approximation. With the new nuclear-physics input, a considerable speeding-up of the r-matter flow is observed, in particular at those r-abundance peaks which are related to magic neutron-shell closures.

Tritium β decay in chiral effective field theory

DOE PAGES

Baroni, A.; Girlanda, L.; Kievsky, A.; ...

2016-08-18

We evaluate the Fermi and Gamow-Teller (GT) matrix elements in tritiummore » $$\\beta$$-decay by including in the charge-changing weak current the corrections up to one loop recently derived in nuclear chiral effective field theory ($$\\chi$$ EFT). The trinucleon wave functions are obtained from hyperspherical-harmonics solutions of the Schroedinger equation with two- and three-nucleon potentials corresponding to either $$\\chi$$ EFT (the N3LO/N2LO combination) or meson-exchange phenomenology (the AV18/UIX combination). We find that contributions due to loop corrections in the axial current are, in relative terms, as large as (and in some cases, dominate) those from one-pion exchange, which nominally occur at lower order in the power counting. Furthermore, we also provide values for the low-energy constants multiplying the contact axial current and three-nucleon potential, required to reproduce the experimental GT matrix element and trinucleon binding energies in the N3LO/N2LO and AV18/UIX calculations.« less

Neutrino-nucleus reactions based on recent structure studies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Toshio; National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588

2015-05-15

Neutrino-nucleus reactions are studied with the use of new shell model Hamiltonians, which have proper tensor components in the interactions and prove to be successful in the description of Gamow-Teller (GT) strengths in nuclei. The new Hamiltonians are applied to obtain new neutrino-nucleus reaction cross sections in {sup 12}C, {sup 13}C, {sup 56}Fe and {sup 56}Ni induced by solar and supernova neutrinos. The element synthesis by neutrino processes in supernova explosions is discussed with the new cross sections. The enhancement of the production yields of {sup 7}Li, {sup 11}B and {sup 55}Mn is obtained while fragmented GT strength in {supmore » 56}Ni with two-peak structure is found to result in smaller e-capture rates at stellar environments. The monopole-based universal interaction with tensor force of π+ρ meson exchanges is used to evaluate GT strength in {sup 40}Ar and ν-induced reactions on {sup 40}Ar. It is found to reproduce well the experimental GT strength in {sup 40}Ar.« less

Quantum Monte Carlo calculations of weak transitions in A = 6 – 10 nuclei

DOE PAGES

Pastore, S.; Baroni, A.; Carlson, J.; ...

2018-02-26

{\\it Ab initio} calculations of the Gamow-Teller (GT) matrix elements in themore » $$\\beta$$ decays of $^6$He and $$^{10}$$C and electron captures in $^7$Be are carried out using both variational and Green's function Monte Carlo wave functions obtained from the Argonne $$v_{18}$$ two-nucleon and Illinois-7 three-nucleon interactions, and axial many-body currents derived from either meson-exchange phenomenology or chiral effective field theory. The agreement with experimental data is excellent for the electron captures in $^7$Be, while theory overestimates the $^6$He and $$^{10}$$C data by $$\\sim 2\\%$$ and $$\\sim 10\\%$$, respectively. We show that for these systems correlations in the nuclear wave functions are crucial to explain the data, while many-body currents increase by $$\\sim 2$$--$$3\\%$$ the one-body GT contributions. These findings suggest that the longstanding $$g_A$$-problem, {\\it i.e.}, the systematic overprediction ($$\\sim 20 \\%$$ in $$A\\le 18$$ nuclei) of GT matrix elements in shell-model calculations, may be resolved, at least partially, by correlation effects.« less

Microbial Community Patterns Associated with Automated Teller Machine Keypads in New York City.

PubMed

Bik, Holly M; Maritz, Julia M; Luong, Albert; Shin, Hakdong; Dominguez-Bello, Maria Gloria; Carlton, Jane M

2016-01-01

In densely populated urban environments, the distribution of microbes and the drivers of microbial community assemblages are not well understood. In sprawling metropolitan habitats, the "urban microbiome" may represent a mix of human-associated and environmental taxa. Here we carried out a baseline study of automated teller machine (ATM) keypads in New York City (NYC). Our goal was to describe the biodiversity and biogeography of both prokaryotic and eukaryotic microbes in an urban setting while assessing the potential source of microbial assemblages on ATM keypads. Microbial swab samples were collected from three boroughs (Manhattan, Queens, and Brooklyn) during June and July 2014, followed by generation of Illumina MiSeq datasets for bacterial (16S rRNA) and eukaryotic (18S rRNA) marker genes. Downstream analysis was carried out in the QIIME pipeline, in conjunction with neighborhood metadata (ethnicity, population, age groups) from the NYC Open Data portal. Neither the 16S nor 18S rRNA datasets showed any clustering patterns related to geography or neighborhood demographics. Bacterial assemblages on ATM keypads were dominated by taxonomic groups known to be associated with human skin communities ( Actinobacteria , Bacteroides , Firmicutes , and Proteobacteria ), although SourceTracker analysis was unable to identify the source habitat for the majority of taxa. Eukaryotic assemblages were dominated by fungal taxa as well as by a low-diversity protist community containing both free-living and potentially pathogenic taxa ( Toxoplasma , Trichomonas ). Our results suggest that ATM keypads amalgamate microbial assemblages from different sources, including the human microbiome, eukaryotic food species, and potentially novel extremophilic taxa adapted to air or surfaces in the built environment. DNA obtained from ATM keypads may thus provide a record of both human behavior and environmental sources of microbes. IMPORTANCE Automated teller machine (ATM) keypads represent

Microbial Community Patterns Associated with Automated Teller Machine Keypads in New York City

PubMed Central

Maritz, Julia M.; Luong, Albert

2016-01-01

ABSTRACT In densely populated urban environments, the distribution of microbes and the drivers of microbial community assemblages are not well understood. In sprawling metropolitan habitats, the “urban microbiome” may represent a mix of human-associated and environmental taxa. Here we carried out a baseline study of automated teller machine (ATM) keypads in New York City (NYC). Our goal was to describe the biodiversity and biogeography of both prokaryotic and eukaryotic microbes in an urban setting while assessing the potential source of microbial assemblages on ATM keypads. Microbial swab samples were collected from three boroughs (Manhattan, Queens, and Brooklyn) during June and July 2014, followed by generation of Illumina MiSeq datasets for bacterial (16S rRNA) and eukaryotic (18S rRNA) marker genes. Downstream analysis was carried out in the QIIME pipeline, in conjunction with neighborhood metadata (ethnicity, population, age groups) from the NYC Open Data portal. Neither the 16S nor 18S rRNA datasets showed any clustering patterns related to geography or neighborhood demographics. Bacterial assemblages on ATM keypads were dominated by taxonomic groups known to be associated with human skin communities (Actinobacteria, Bacteroides, Firmicutes, and Proteobacteria), although SourceTracker analysis was unable to identify the source habitat for the majority of taxa. Eukaryotic assemblages were dominated by fungal taxa as well as by a low-diversity protist community containing both free-living and potentially pathogenic taxa (Toxoplasma, Trichomonas). Our results suggest that ATM keypads amalgamate microbial assemblages from different sources, including the human microbiome, eukaryotic food species, and potentially novel extremophilic taxa adapted to air or surfaces in the built environment. DNA obtained from ATM keypads may thus provide a record of both human behavior and environmental sources of microbes. IMPORTANCE Automated teller machine (ATM) keypads

Advisor-Teller Money Manager (ATM) Therapy for Substance Use Disorders

PubMed Central

Rosen, Marc I.; Rounsaville, Bruce J.; Ablondi, Karen; Black, Anne C.; Rosenheck, Robert A.

2011-01-01

Objective Patients with concomitant psychiatric and substance use disorders are commonly assigned representative payees or case managers to help manage their funds, but money management has not been conceptualized as a theory-based treatment. This randomized clinical trial was conducted to determine the effect of a money management–based therapy, advisor-teller money manager (ATM), on substance abuse or dependence. Methods Ninety patients at a community mental health center who had a history of cocaine or alcohol abuse or dependence were assessed after random assignment to 36 weeks of ATM (N=47) or a control condition in which use of a financial workbook was reviewed (N=43). Patients assigned to ATM were encouraged to deposit their funds into a third-party account, plan weekly expenditures, and negotiate monthly budgets. Substance use calendars and urine toxicology tests were collected every other week for 36 weeks and again 52 weeks after randomization. Results Patients assigned to ATM had significantly more negative toxicologies for cocaine metabolite over time than patients in the control group, and treating clinicians rated ATM patients as significantly more likely to be abstinent from illicit drugs. Self-reported abstinence from alcohol did not significantly differ between groups. Unexpectedly, patients assigned to ATM were more likely to be assigned a representative payee or a conservator than control participants during the follow-up period (ten of 47 versus two of 43). One patient in ATM assaulted the therapist when his check had not arrived. Conclusions ATM is an efficacious therapy for the treatment of cocaine abuse or dependence among people with concomitant psychiatric illness but requires protection of patient autonomy and staff safety. PMID:20592006

Advisor-Teller Money Manager (ATM) therapy for substance use disorders.

PubMed

Rosen, Marc I; Rounsaville, Bruce J; Ablondi, Karen; Black, Anne C; Rosenheck, Robert A

2010-07-01

Patients with concomitant psychiatric and substance use disorders are commonly assigned representative payees or case managers to help manage their funds, but money management has not been conceptualized as a theory-based treatment. This randomized clinical trial was conducted to determine the effect of a money management-based therapy, advisor-teller money manager (ATM), on substance abuse or dependence. Ninety patients at a community mental health center who had a history of cocaine or alcohol abuse or dependence were assessed after random assignment to 36 weeks of ATM (N=47) or a control condition in which use of a financial workbook was reviewed (N=43). Patients assigned to ATM were encouraged to deposit their funds into a third-party account, plan weekly expenditures, and negotiate monthly budgets. Substance use calendars and urine toxicology tests were collected every other week for 36 weeks and again 52 weeks after randomization. Patients assigned to ATM had significantly more negative toxicologies for cocaine metabolite over time than patients in the control group, and treating clinicians rated ATM patients as significantly more likely to be abstinent from illicit drugs. Self-reported abstinence from alcohol did not significantly differ between groups. Unexpectedly, patients assigned to ATM were more likely to be assigned a representative payee or a conservator than control participants during the follow-up period (ten of 47 versus two of 43). One patient in ATM assaulted the therapist when his check had not arrived. ATM is an efficacious therapy for the treatment of cocaine abuse or dependence among people with concomitant psychiatric illness but requires protection of patient autonomy and staff safety.

Unconventional high-Tc superconductivity in fullerides

PubMed Central

Takabayashi, Yasuhiro; Prassides, Kosmas

2016-01-01

A3C60 molecular superconductors share a common electronic phase diagram with unconventional high-temperature superconductors such as the cuprates: superconductivity emerges from an antiferromagnetic strongly correlated Mott-insulating state upon tuning a parameter such as pressure (bandwidth control) accompanied by a dome-shaped dependence of the critical temperature, Tc. However, unlike atom-based superconductors, the parent state from which superconductivity emerges solely by changing an electronic parameter—the overlap between the outer wave functions of the constituent molecules—is controlled by the C603− molecular electronic structure via the on-molecule Jahn–Teller effect influence of molecular geometry and spin state. Destruction of the parent Mott–Jahn–Teller state through chemical or physical pressurization yields an unconventional Jahn–Teller metal, where quasi-localized and itinerant electron behaviours coexist. Localized features gradually disappear with lattice contraction and conventional Fermi liquid behaviour is recovered. The nature of the underlying (correlated versus weak-coupling Bardeen–Cooper–Schrieffer theory) s-wave superconducting states mirrors the unconventional/conventional metal dichotomy: the highest superconducting critical temperature occurs at the crossover between Jahn–Teller and Fermi liquid metal when the Jahn–Teller distortion melts. This article is part of the themed issue ‘Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene’. PMID:27501971

The beta-delayed particle decay of neon-17

NASA Astrophysics Data System (ADS)

Morton, Anthony Colin

2001-10-01

An experiment has been proposed to study the β- delayed proton decay of 17Ne into α- particle-emitting states in 16O below the 12C + α threshold in the hopes of using the information gained to constrain the 12C(α, γ) 16O cross section at stellar energies; several experiments have been carried out using the TISOL facility at TRIUMF in an effort to determine the feasibility of such an approach. 17Ne decays by β-particle emission to excited states in 17F; by studying proton-γ-ray coincidences in the decay of these states, relative branching ratios have been obtained for the β-delayed proton decay of 17Ne to γ-ray-emitting states in 16O. These indicate that the decay of the isobaric analogue state (IAS) at 11.1929 MeV in 17F to the 2 + subthreshold state at 6.917 MeV in 16O is a factor of thirty weaker than that of the IAS to any other γ- emitting state. From measurements of the angular correlations observed in such coincidences, the spins and parities of several excited states in 17F have been determined; it has also been shown that the decay of the IAS to the 1 - subthreshold state at 7.117 MeV in 16O is strongly anisotropic, suggesting that it has a strong l = 2 component. Further decay studies have yielded a comprehensive set of β-delayed particle branching ratios from the decay of 17Ne; from these, fAt values and reduced Gamow-Teller matrix elements have been calculated, and the Fermi decay strength of the IAS has been limited to >=2.96 +/- 0.14 indicating a T = / isospin purity of >=98.7 +/- 4.6% for the IAS. The results obtained suggest that a determination of both the E1 and E2 components of the 12C(α, γ) 16O cross section is not feasible; however, with improved yields of 17Ne, a determination of only the E1 component should be.

Fast computation of the Gauss hypergeometric function with all its parameters complex with application to the Pöschl Teller Ginocchio potential wave functions

NASA Astrophysics Data System (ADS)

Michel, N.; Stoitsov, M. V.

2008-04-01

The fast computation of the Gauss hypergeometric function F12 with all its parameters complex is a difficult task. Although the F12 function verifies numerous analytical properties involving power series expansions whose implementation is apparently immediate, their use is thwarted by instabilities induced by cancellations between very large terms. Furthermore, small areas of the complex plane, in the vicinity of z=e, are inaccessible using F12 power series linear transformations. In order to solve these problems, a generalization of R.C. Forrey's transformation theory has been developed. The latter has been successful in treating the F12 function with real parameters. As in real case transformation theory, the large canceling terms occurring in F12 analytical formulas are rigorously dealt with, but by way of a new method, directly applicable to the complex plane. Taylor series expansions are employed to enter complex areas outside the domain of validity of power series analytical formulas. The proposed algorithm, however, becomes unstable in general when |a|, |b|, |c| are moderate or large. As a physical application, the calculation of the wave functions of the analytical Pöschl-Teller-Ginocchio potential involving F12 evaluations is considered. Program summaryProgram title: hyp_2F1, PTG_wf Catalogue identifier: AEAE_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEAE_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.: 6839 No. of bytes in distributed program, including test data, etc.: 63 334 Distribution format: tar.gz Programming language: C++, Fortran 90 Computer: Intel i686 Operating system: Linux, Windows Word size: 64 bits Classification: 4.7 Nature of problem: The Gauss hypergeometric function F12, with all its parameters complex, is uniquely

Nonadiabatic dynamics of O(1D) + N2(X1Σg+) → O(3P) + N2(X1Σg+) on three coupled potential surfaces: symmetry, Coriolis, spin-orbit, and Renner-Teller effects.

PubMed

Defazio, Paolo; Gamallo, Pablo; Petrongolo, Carlo

2012-02-07

We present the spin-orbit (SO) and Renner-Teller (RT) quantum dynamics of the spin-forbidden quenching O((1)D) + N(2)(X(1)Σ(g)(+)) → O((3)P) + N(2)(X(1)Σ(g)(+)) on the N(2)O X(1)A', ã(3)A", and b(3)A' coupled PESs. We use the permutation-inversion symmetry, propagate coupled-channel (CC) real wavepackets, and compute initial-state-resolved probabilities and cross sections σ(j(0)) for the ground vibrational and the first two rotational states of N(2), j(0) = 0 and 1. Labeling symmetry angular states by j and K, we report selection rules for j and for the minimum K value associated with any electronic state, showing that ã(3)A" is uncoupled in the centrifugal-sudden (CS) approximation at j(0) = 0. The dynamics is resonance-dominated, the probabilities are larger at low K, σ(j(0)) decrease with the collision energy and increase with j(0), and the CS σ(0) is lower than the CC one. The nonadiabatic interactions play different roles on the quenching dynamics, because the X(1)A'-b(3)A' SO effects are those most important while the ã(3)A"-b(3)A' RT ones are negligible.

Bond-length fluctuations and the spin-state transition in LCoO3 (L=La, Pr, and Nd)

NASA Astrophysics Data System (ADS)

Yan, J.-Q.; Zhou, J.-S.; Goodenough, J. B.

2004-04-01

The temperature dependence of thermal conductivity, κ(T), and magnetic susceptibility, χ(T), have been measured on single crystals of LCoO3 (L=La, Pr, Nd) grown by the floating-zone method. The susceptibility measurement shows a progressive stabilization of the low-spin (LS) state of Co(III) with decreasing size of the L3+ ion, and the population of excited intermediate-spin (IS) or high-spin (HS) state Co(III) ions begins to increase at 200 K and 300 K for PrCoO3 and NdCoO3 compared with 35 K in LaCoO3. The low-temperature Curie-Weiss paramagnetic susceptibility of LCoO3 is an intrinsic property arising from surface cobalt and, possibly, a LS ground state bearing some IS character caused by the virtual excitation to the IS state. The transition from a LS to a IS/HS state introduces bond-length fluctuations that suppress the phonon contribution to κ(T) below 300 K. The suppressed κ(T) could be further reduced by dynamic Jahn-Teller distortions associated with the IS/HS species. A smooth transition in ρ(T) and α(T) and a nearly temperature independent α(T)≈20 μV/K above 600 K do not support a thermally induced, homogeneous Mott-Hubbard transition model for the high-temperature transition of LaCoO3 from an insulating to a conductive state. A two-phase process is proposed for the interval 300 Kstates with localized e electrons that are stabilized by Jahn-Teller distortions that may be dynamic.

On the Mechanism of D-Wave High TC Superconductivity by the Interplay of Jahn-Teller Physics and Mott Physics

NASA Astrophysics Data System (ADS)

Ushio, H.; Matsuno, S.; Kamimura, H.

2011-01-01

In the present paper we will discuss two important roles of the interplay of Jahn-Teller physics and Mott physics. One is the small Fermi surface. The "Fermi arcs" observed in ARPES should be one of the edges of small Fermi pockets, based on the Kamimura-Suwa model (K-S model). This prediction is consistent with ARPES results by Tanaka et al. Another is the mechanism of superconductivity in cuprates. This can be explained by the interplay of strong electron-phonon interactions and local AF order. It is shown that the characteristic phase difference of wave functions between up- and down-spin carriers in the presence of the local AF order leads to the superconducting gap of dx2-y2 symmetry even in the phonon-involved mechanism.

Unconventional high-Tc superconductivity in fullerides.

PubMed

Takabayashi, Yasuhiro; Prassides, Kosmas

2016-09-13

A3C60 molecular superconductors share a common electronic phase diagram with unconventional high-temperature superconductors such as the cuprates: superconductivity emerges from an antiferromagnetic strongly correlated Mott-insulating state upon tuning a parameter such as pressure (bandwidth control) accompanied by a dome-shaped dependence of the critical temperature, Tc However, unlike atom-based superconductors, the parent state from which superconductivity emerges solely by changing an electronic parameter-the overlap between the outer wave functions of the constituent molecules-is controlled by the C60 (3-) molecular electronic structure via the on-molecule Jahn-Teller effect influence of molecular geometry and spin state. Destruction of the parent Mott-Jahn-Teller state through chemical or physical pressurization yields an unconventional Jahn-Teller metal, where quasi-localized and itinerant electron behaviours coexist. Localized features gradually disappear with lattice contraction and conventional Fermi liquid behaviour is recovered. The nature of the underlying (correlated versus weak-coupling Bardeen-Cooper-Schrieffer theory) s-wave superconducting states mirrors the unconventional/conventional metal dichotomy: the highest superconducting critical temperature occurs at the crossover between Jahn-Teller and Fermi liquid metal when the Jahn-Teller distortion melts.This article is part of the themed issue 'Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene'. © 2016 The Author(s).

Geochemical reanalysis of historical U.S. Geological Survey sediment samples from the Kougarok area, Bendeleben and Teller quadrangles, Seward Peninsula, Alaska

USGS Publications Warehouse

Werdon, Melanie B.; Granitto, Matthew; Azain, Jaime S.

2015-01-01

The State of Alaska’s Strategic and Critical Minerals (SCM) Assessment project, a State-funded Capital Improvement Project (CIP), is designed to evaluate Alaska’s statewide potential for SCM resources. The SCM Assessment is being implemented by the Alaska Division of Geological & Geophysical Surveys (DGGS), and involves obtaining new airborne-geophysical, geological, and geochemical data. As part of the SCM Assessment, thousands of historical geochemical samples from DGGS, U.S. Geological Survey (USGS), and U.S. Bureau of Mines archives are being reanalyzed by DGGS using modern, quantitative, geochemical-analytical methods. The objective is to update the statewide geochemical database to more clearly identify areas in Alaska with SCM potential. The USGS is also undertaking SCM-related geologic studies in Alaska through the federally funded Alaska Critical Minerals cooperative project. DGGS and USGS share the goal of evaluating Alaska’s strategic and critical minerals potential and together created a Letter of Agreement (signed December 2012) and a supplementary Technical Assistance Agreement (#14CMTAA143458) to facilitate the two agencies’ cooperative work. Under these agreements, DGGS contracted the USGS in Denver to reanalyze historical USGS sediment samples from Alaska. For this report, DGGS funded reanalysis of 302 historical USGS sediment samples from the statewide Alaska Geochemical Database Version 2.0 (AGDB2; Granitto and others, 2013). Samples were chosen from the Kougarok River drainage as well as smaller adjacent drainages in the Bendeleben and Teller quadrangles, Seward Peninsula, Alaska (fig. 1). The USGS was responsible for sample retrieval from the National Geochemical Sample Archive (NGSA) in Denver, Colorado through the final quality assurance/quality control (QA/QC) of the geochemical analyses obtained through the USGS contract lab. The new geochemical data are published in this report as a coauthored DGGS report, and will be incorporated

Ab initio study of the ground state surface of Cu3

NASA Technical Reports Server (NTRS)

Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.; Walch, Stephen P.; Laskowski, Bernard C.

1986-01-01

The ground state surface of the metallic trimer Cu3 is investigated theoretically. Relativistic and correlation effects are taken into account in ab initio computations, which are calibrated against analogous computations for the 1Sigma(g)+ state of Cu2; the results are presented in tables and analyzed. The Cu3 ground state is found to have a 2B2 C(2v) structure with angle greater than 60 deg, lying 59/cm below a 2A1 C(2v) geometry and 280/cm below the D(3h) equilateral geometry. These findings are shown to be in good agreement with the experimental measurements of Rohlfing and Valentini (1986) and their analysis (in terms of a Jahn-Teller distortion of 2E-prime equilateral-triangle geometry) by Truhlar et al. (1986).

Density functional theory study on Herzberg-Teller contribution in Raman scattering from 4-aminothiophenol-metal complex and metal-4-aminothiophenol-metal junction

NASA Astrophysics Data System (ADS)

Liu, Shasha; Zhao, Xiuming; Li, Yuanzuo; Zhao, Xiaohong; Chen, Maodu

2009-06-01

Density functional theory (DFT) and time-dependent DFT calculations have been performed to investigate the Raman scattering spectra of metal-molecule complex and metal-molecule-metal junction architectures interconnected with 4-aminothiophenol (PATP) molecule. The simulated profiles of normal Raman scattering (NRS) spectra for the two complexes (Ag2-PATP and PATP-Au2) and the two junctions (Ag2-PATP-Au2 and Au2-PATP-Ag2) are similar to each other, but exhibit obviously different Raman intensities. Due to the lager static polarizabilities of the two junctions, which directly influence the ground state chemical enhancement in NRS spectra, the calculated normal Raman intensities of them are stronger than those of two complexes by the factor of 102. We calculate preresonance Raman scattering (RRS) spectra with incident light at 1064 nm, which is much lower than the S1 electronic transition energy of complexes and junctions. Ag2-PATP-Au2 and Au2-PATP-Ag2 junctions yield higher Raman intensities than those of Ag2-PATP and PATP-Au2 complexes, especially for b2 modes. This effect is mainly attributed to charge transfer (CT) between the metal gap and the PAPT molecule which results in the occurrence of CT resonance enhancement. The calculated pre-RRS spectra strongly depend on the electronic transition state produced by new structures. With excitation at 514.5 nm, the calculated pre-RRS spectra of two complexes and two junctions are stronger than those of with excitation at 1064 nm. A charge difference densities methodology has been used to visually describe chemical enhancement mechanism of RRS spectrum. This methodology aims at visualizing intermolecular CT which provides direct evidence of the Herzberg-Teller mechanism.

High-pressure behavior of cuprospinel CuFe 2O 4: Influence of the Jahn-Teller effect on the spinel structure

DOE PAGES

Kyono, Atsushi; Gramsch, Stephen A.; Nakamoto, Yuki; ...

2015-08-14

The Jahn-Teller-effect at Cu 2+ in cuprospinel CuFe 2O 4 was investigated using high-pressure, single crystal synchrotron x-ray diffraction (XRD) techniques at beamline BL10A at the Photon Factory, KEK, Japan. Six data sets were collected in the pressure range from ambient to 5.9 GPa at room temperature. Structural refinements based on the data were performed at 0.0, 1.8, 2.7, and 4.6 GPa. The unit cell volume of cuprospinel decreases continuously from 590.8 (6) Å 3 to 579.5 (8) Å 3 up to 3.8 GPa. Leastsquares fitting to a third-order Birch-Murnaghan equation of state yields zero-pressure volume V 0 = 590.7more » (1) Å 3 and bulk modulus K 0 = 188.1 (4.4) GPa with K’ fixed at 4.0. The crystal chemical composition determined by electron-probe analysis and x-ray site-occupancy refinement is represented as [Cu 0.526Fe 0.474] [6][Cu 0.074Fe 1.926]O 4. Most of the Cu 2+ are preferentially distributed onto the tetrahedral (T) site of the spinel structure. At 4.6 GPa, a cubic-tetragonal phase transition is indicated by a splitting of the a axis of the cubic structure into a smaller a axis and a longer c axis, with unit cell parameters a = 5.882 (1) Å and c = 8.337 (1) Å. The tetragonal crystal structure with space group I4 1/amd was refined to R1 = 0.0182 and wR2 = 0.0134 using observed 35 x-ray reflections. At the T site, the tetrahedral O-T-O bond angles along the c-axis direction of the unit cell decreases slightly from 109.47 ° to 108.7 (4) °, which generates a stretched tetrahedral geometry along the c-axis. The cubic-totetragonal transition induced by the Jahn-Teller effect at Cu 2+ is attributable to the angular distortion at the tetrahedral site. At the octahedral (M) site, on the other hand, the two M-O bonds parallel to the caxis are shortened with respect to the four M-O bonds parallel to the ab-plane, which are lengthened as a result of the phase transition, leading to a compressed octahedral geometry along the c-axis. With the competing distortions

Renormalization of the weak hadronic current in the nuclear medium

NASA Astrophysics Data System (ADS)

Siiskonen, T.; Hjorth-Jensen, M.; Suhonen, J.

2001-05-01

The renormalization of the weak charge-changing hadronic current as a function of the reaction energy release is studied at the nucleonic level. We have calculated the average quenching factors for each type of current (vector, axial vector, and induced pseudoscalar). The obtained quenching in the axial vector part is, at zero momentum transfer, 19% for the 1s0d shell and 23% in the 1p0f shell. We have extended the calculations also to heavier systems such as 56Ni and 100Sn, where we obtain stronger quenchings, 44% and 59%, respectively. Gamow-Teller-type transitions are discussed, along with the higher-order matrix elements. The quenching factors are constant up to roughly 60 MeV momentum transfer. Therefore the use of energy-independent quenching factors in beta decay is justified. We also found that going beyond the zeroth and first order operators (in inverse nucleon mass) does not give any substantial contribution. The extracted renormalization to the ratio CP/CA at q=100 MeV is -3.5%, -7.1%, -28.6%, and +8.7% for mass 16, 40, 56, and 100, respectively.

Symmetry breaking in the planar configurations of disilicon tetrahalides: Pseudo-Jahn-Teller effect parameters, hardness and electronegativity.

PubMed

Kouchakzadeh, Ghazaleh; Nori-Shargh, Davood

2015-11-21

CCSD(T), MP2, LC-BLYP, LC-ωPBE and B3LYP methods with the Def2-TZVPP basis set and natural bond orbital (NBO) interpretations were performed to investigate the correlations between the Pseudo-Jahn-Teller Effect (PJTE) parameters [i.e. vibronic coupling constant values (F), energy gaps between reference states (Δ) and the primary force constant (K0)], structural and configurational properties, global hardness, global electronegativity, natural bond orders, stabilization energies associated with electron delocalizations and natural atomic charges of disilicon tetrafluoride (1), disilicon tetrachloride (2), disilicon tetrabromide (3) and disilicon tetraiodide (4). All levels of theory showed the trans-bent (C2h) configurations as the energy minimum structures of compounds 1-4, and the flap angles between the X2Si planes and the Si=Si bonds in the distorted (C2h) configurations decrease from compound 1 to compound 4. The negative curvatures of the ground state electronic configurations and the positive curvatures of the excited states of the adiabatic potential energy surfaces (APESs) which resulted from the mixing of the ground Ag and excited B2g states are due to the PJTE (i.e. PJT(Ag + B2g) ⊗ b2g problem). Contrary to the usual expectation, with the decrease of the energy gaps between reference states (Δ), the PJTE stabilization energy, E(PJT), decreases from compound 1 to compound 4. The canonical molecular orbital (CMO) analysis revealed that the contributions of the ψ(HOMO)(b3u) and ψL(UMO)(b1u) molecular orbitals in the vibronic coupling constant (F) decrease from compound 1 to compound 4. This fact clearly justifies the decrease of the vibronic coupling constant (F) and the primary force constant (the force constant without the PJTE) values on going from compound 1 to compound 4, leading to the decrease of the negative curvatures of the ground state electronic configuration curves of their corresponding APESs. The results obtained showed that the

The entangled triplet pair state in acene and heteroacene materials

NASA Astrophysics Data System (ADS)

Yong, Chaw Keong; Musser, Andrew J.; Bayliss, Sam L.; Lukman, Steven; Tamura, Hiroyuki; Bubnova, Olga; Hallani, Rawad K.; Meneau, Aurélie; Resel, Roland; Maruyama, Munetaka; Hotta, Shu; Herz, Laura M.; Beljonne, David; Anthony, John E.; Clark, Jenny; Sirringhaus, Henning

2017-07-01

Entanglement of states is one of the most surprising and counter-intuitive consequences of quantum mechanics, with potent applications in cryptography and computing. In organic materials, one particularly significant manifestation is the spin-entangled triplet-pair state, which mediates the spin-conserving fission of one spin-0 singlet exciton into two spin-1 triplet excitons. Despite long theoretical and experimental exploration, the nature of the triplet-pair state and inter-triplet interactions have proved elusive. Here we use a range of organic semiconductors that undergo singlet exciton fission to reveal the photophysical properties of entangled triplet-pair states. We find that the triplet pair is bound with respect to free triplets with an energy that is largely material independent (~30 meV). During its lifetime, the component triplets behave cooperatively as a singlet and emit light through a Herzberg-Teller-type mechanism, resulting in vibronically structured photoluminescence. In photovoltaic blends, charge transfer can occur from the bound triplet pairs with >100% photon-to-charge conversion efficiency.

An Anomaly in the Inglis-Teller Limits of the C VI Lyman and Balmer Series in Laser-Produced Plasmas

NASA Astrophysics Data System (ADS)

Elton, R.; Iglesias, E.; Griem, H.; Weaver, J.; Pien, G.; Mancini, R.

2002-11-01

Soft x-ray spectra from thin carbon layers heated by the OMEGA and NIKE lasers have been obtained with both spherical and planar targets, respectively, using a flat-field grazing incidence spectrograph equipped with a gated microchannel plate for temporal resolution. In both experiments, late-time (recombining) hydrogenic C VI spectra show an n-to-1 Lyman spectral series blending with the continuum at n=4, contrary to n=9 in the n-to-2 Balmer series. It appears unlikely that plasma inhomogeneities are the sole cause of this anomaly, given the difference in the experimental configurations. Other explanations for the line-to-continuum merging (other than the usual Stark-broadened Inglis-Teller effect) under consideration include non-thermal Doppler broadening, deviations from statistical sublevel population distributions, and opacity effects. Collisional-radiative and hydrodynamic modeling, including cascades, is employed to further understand this phenomenon.

The 10B(p,α)7Be S(E)-factor from 5 keV to 1.5 MeV using the Trojan Horse Method

NASA Astrophysics Data System (ADS)

Puglia, Sebastiana Maria Regina; Spitaleri, Claudio; La Cognata, Marco; Lamia, Livio; Broggini, Carlo; Caciolli, Antonio; Carlin, Nelson; Cherubini, Silvio; Cvetinovic, Alexandra; D'Agata, Giuseppe; Dell'aquila, Daniele; Depalo, Rosanna; Gulino, Marisa; Guardo, Giovanni Luca; Indelicato, Iolanda; Lombardo, Ivano; Menegazzo, Roberto; Munhoz, Marcelo Gimenez; Pizzone, Rosario Gianluca; Rapisarda, Giuseppe Gabriele; Rigato, Valentino; Romano, Stefano; Sergi, Maria Letizia; Souza, Francisco; Sparta, Roberta; Tudisco, Salvo; Tumino, Aurora

2018-01-01

The 10B(p,α)7Be reaction is the main responsible for the 10B destruction in stellar interior [1]. In such environments this p-capture process occurs at a Gamow energy of 10 keV and takes places mainly through a resonant state (Ex = 8.701 MeV) of the compound 11C nucleus. Thus a resonance right in the region of the Gamow peak is expected to significantly influence the behavior of the astrophysical S(E)-factor. The 10B(p,α)7Be reaction was studied via the Trojan Horse Method (THM) applied to the 2H(10B,α7Be)n in order to extract the astrophysical S(E)-factor in a wide energy range from 5 keV to 1.5 MeV.

Antibiogram of bacteria isolated from automated teller machines in Hamadan, West Iran

PubMed Central

Mahmoudi, Hassan; Arabestani, Mohammad Reza; Alikhani, Mohammad Yousef; Sedighi, Iraj; Kohan, Hamed Farhadi; Molavi, Mohammad

2017-01-01

Aim: Bacteria are ubiquitous in the environment. In keeping with the continued expansion of urbanization and the growing population, an increasing number of people use automated banking, i.e. automated teller machines (ATMs). The aim of this study was to investigate the bacterial contamination and its antibiotic sensitivity on computer keyboards located at ATMs in Hamadan province, Iran. Method: Out of 360 ATMs at four locations in Hamadan, 96 were randomly selected for this study. The antibiotic susceptibility pattern of all isolates was determined by the agar disk diffusion method using gentamicin (10 µg), vancomycin (30 µg), trimethoprim/sulfamethoxazole (25 µg), amikacin (30 µg), tobramycin (10 µg), cephalotin (30 µg), norfloxacin (5 µg), and ceftizoxim (30 µg) disks. Results: Melli and Saderat Banks had the most frequently contaminated ATMS, with 18 (27.7%) and 12 (18.5%), respectively. The most frequently isolated bacteria were Staphylococcus epidermidis in 12 (18.5%) ATMs, Pseudomonas aeruginosa in 12 (18.5%), Bacillus subtilis in 11 (16.9%), Escherichia coli in 6 (9.2%), Klebsiella spp. in 8 (12.3%), Enterobacter spp. in 2 (3.1%), Bacillus cereus in 6 (9.2%), Staphylococcus aureus in 3 (4.6%), and Micrococcaceae spp. in 5 (7.69%) cases. All isolated bacteria were susceptible to gentamicin, cephalotin, tobramycin, amikacin, norfloxacin, and vancomycin. The S. aureus resistance rate to trimethoprim/sulfamethoxazole was 50%. Conclusion: All tested ATM keyboards were contaminated with at least one species of bacteria. Based on these findings, it is recommendable to disinfect the hands after entering one’s own apartment, work area or a hospital, in order to hinder the spread of critical pathogens in the personal environment or in the hospital. PMID:28197394

Free H₂ rotation vs Jahn-Teller constraints in the nonclassical trigonal (TPB)Co-H₂ complex.

PubMed

Gunderson, William A; Suess, Daniel L M; Fong, Henry; Wang, Xiaoping; Hoffmann, Christina M; Cutsail, George E; Peters, Jonas C; Hoffman, Brian M

2014-10-22

Proton exchange within the M-H2 moiety of (TPB)Co(H2) (Co-H2; TPB = B(o-C6H4P(i)Pr2)3) by 2-fold rotation about the M-H2 axis is probed through EPR/ENDOR studies and a neutron diffraction crystal structure. This complex is compared with previously studied (SiP(iPr)3)Fe(H2) (Fe-H2) (SiP(iPr)3 = [Si(o-C6H4P(i)Pr2)3]). The g-values for Co-H2 and Fe-H2 show that both have the Jahn-Teller (JT)-active (2)E ground state (idealized C3 symmetry) with doubly degenerate frontier orbitals, (e)(3) = [|mL ± 2>](3) = [x(2) - y(2), xy](3), but with stronger linear vibronic coupling for Co-H2. The observation of (1)H ENDOR signals from the Co-HD complex, (2)H signals from the Co-D2/HD complexes, but no (1)H signals from the Co-H2 complex establishes that H2 undergoes proton exchange at 2 K through rotation around the Co-H2 axis, which introduces a quantum-statistical (Pauli-principle) requirement that the overall nuclear wave function be antisymmetric to exchange of identical protons (I = 1/2; Fermions), symmetric for identical deuterons (I = 1; Bosons). Analysis of the 1-D rotor problem indicates that Co-H2 exhibits rotor-like behavior in solution because the underlying C3 molecular symmetry combined with H2 exchange creates a dominant 6-fold barrier to H2 rotation. Fe-H2 instead shows H2 localization at 2 K because a dominant 2-fold barrier is introduced by strong Fe(3d)→ H2(σ*) π-backbonding that becomes dependent on the H2 orientation through quadratic JT distortion. ENDOR sensitively probes bonding along the L2-M-E axis (E = Si for Fe-H2; E = B for Co-H2). Notably, the isotropic (1)H/(2)H hyperfine coupling to the diatomic of Co-H2 is nearly 4-fold smaller than for Fe-H2.

Born-Oppenheimer and Renner-Teller coupled-channel quantum reaction dynamics of O((3)P) + H2(+)(X(2)Σg(+)) collisions.

PubMed

Gamallo, Pablo; Defazio, Paolo; González, Miguel; Paniagua, Miguel; Petrongolo, Carlo

2015-09-28

We present Born-Oppenheimer (BO) and Renner-Teller (RT) time dependent quantum dynamics studies of the reactions O((3)P) + H2(+)(X(2)Σg(+)) → OH(+)(X(3)Σ(-)) + H((2)S) and OH(X(2)Π) + H(+). We consider the OH2(+) X[combining tilde](2)A'' and Ã(2)A' electronic states that correlate with a linear (2)Π species. The electronic angular momenta operators L[combining circumflex] and L[combining circumflex](2) are considered in nonadiabatic coupled-channel calculations, where the associated RT effects are due to diagonal V(RT) potentials that add up to the PESs and to off-diagonal C(RT) couplings between the potential energy surfaces (PESs). Initial-state-resolved reaction probabilities PI, integral cross sections σI, and rate constants kI are obtained using recent ab initio PESs and couplings and the real wavepacket formalism. Because the PESs are strongly attractive, PI have no threshold energy and are large, σI decrease with collision energy, and kI depend little on the temperature. The X[combining tilde](2)A'' PES is up to three times more reactive than the Ã(2)A' PES and H2(+) rotational effects (j0 = 0, 1) are negligible. The diagonal V(RT) potentials are strongly repulsive at the collinearity and nearly halve all low-energy observables with respect to the BO ones. The off-diagonal C(RT) couplings are important at low partial waves, where they mix the X[combining tilde](2)A'' and Ã(2)A' states up to ∼20%. However, V(RT) effects predominate over the C(RT) ones that change at most by ∼19% the BO values of σI and kI. The reaction O((3)P) + H2(+)(X(2)Σg(+)) → OH(+)(X(3)Σ(-)) + H((2)S) is probably one of the most reactive atom + diatom collisions because its RT rate constant at room temperature is equal to 2.26 × 10(-10) cm(3) s(-1). Within the BO approximation, the present results agree rather well with recent quasiclassical and centrifugal-sudden data using the same PESs.

Exploring Renner-Teller induced quenching in the reaction H(2S)+NH(a 1Delta): a combined experimental and theoretical study.

PubMed

Adam, L; Hack, W; McBane, G C; Zhu, H; Qu, Z-W; Schinke, R

2007-01-21

Experimental rate coefficients for the removal of NH(a (1)Delta) and ND(a (1)Delta) in collisions with H and D atoms are presented; all four isotope combinations are considered: NH+H, NH+D, ND+H, and ND+D. The experiments were performed in a quasistatic laser-flash photolysis/laser-induced fluorescence system at low pressures. NH(a (1)Delta) and ND(a (1)Delta) were generated by photolysis of HN(3) and DN(3), respectively. The total removal rate coefficients at room temperature are in the range of (3-5)x10(13) cm(3) mol(-1) s(-1). For two isotope combinations, NH+H and NH+D, quenching rate coefficients for the production of NH(X (3)Sigma(-)) or ND(X (3)Sigma(-)) were also determined; they are in the range of 1 x 10(13) cm(3) mol(-1) s(-1). The quenching rate coefficients directly reflect the strength of the Renner-Teller coupling between the (2)A(") and (2)A(') electronic states near linearity and so can be used to test theoretical models for describing this nonadiabatic process. The title reaction was modeled with a simple surface-hopping approach including a single parameter, which was adjusted to reproduce the quenching rate for NH+H; the same parameter value was used for all isotope combinations. The agreement with the measured total removal rate is good for all but one isotope combination. However, the quenching rates for the NH+D combination are only in fair (factor of 2) agreement with the corresponding measured data.

Experimental and theoretical identification of the Fe(vii) oxidation state in FeO4.

PubMed

Lu, Jun-Bo; Jian, Jiwen; Huang, Wei; Lin, Hailu; Li, Jun; Zhou, Mingfei

2016-11-16

The experimentally known highest oxidation state of iron has been determined to be Fe(vi) so far. Here we report a combined matrix-isolation infrared spectroscopic and theoretical study of two interconvertible iron oxide anions: a dioxoiron peroxide complex [(η 2 -O 2 )FeO 2 ] - with a C 2v -structure and a tetroxide FeO 4 - with a D 2d tetrahedral structure, which are formed by co-condensation of laser-ablated iron atoms and electrons with O 2 /Ar mixtures at 4 K. Quantum chemistry theoretical studies indicate that the Jahn-Teller distorted tetroxide FeO 4 - anion is a d 1 species with hereto the highest iron formal oxidation state Fe(vii).

Photodissociation dynamics in the first absorption band of pyrrole. I. Molecular Hamiltonian and the Herzberg-Teller absorption spectrum for the A12(π σ* ) ←X˜ 1 A1(π π ) transition

NASA Astrophysics Data System (ADS)

Picconi, David; Grebenshchikov, Sergy Yu.

2018-03-01

This paper opens a series in which the photochemistry of the two lowest πσ* states of pyrrole and their interaction with each other and with the ground electronic state X ˜ are studied using ab initio quantum mechanics. New 24-dimensional potential energy surfaces for the photodissociation of the N-H bond and the formation of the pyrrolyl radical are calculated using the multiconfigurational perturbation theory (CASPT2) for the electronic states X ˜ (π π ) , 11A2(πσ*), and 11B1(πσ*) and locally diabatized. In this paper, the ab initio calculations are described and the photodissociation in the state 11A2(πσ*) is analyzed. The excitation 11 A2←X ˜ is mediated by the coordinate dependent transition dipole moment functions constructed using the Herzberg-Teller expansion. Nuclear dynamics, including 6, 11, and 15 active degrees of freedom, are studied using the multi-configurational time-dependent Hartree method. The focus is on the frequency resolved absorption spectrum as well as on the dissociation time scales and the resonance lifetimes. Calculations are compared with available experimental data. An approximate convolution method is developed and validated, with which absorption spectra can be calculated and assigned in terms of vibrational quantum numbers. The method represents the total absorption spectrum as a convolution of the diffuse spectrum of the detaching H-atom and the Franck-Condon spectrum of the heteroaromatic ring. Convolution calculation requires a minimal quantum chemical input and is a promising tool for studying the πσ* photodissociation in model biochromophores.

Ne matrix spectra of the sym-C6Br3F3+ radical cation

USGS Publications Warehouse

Bondybey, V.E.; Sears, T.J.; Miller, T.A.; Vaughn, C.; English, J.H.; Shiley, R.S.

1981-01-01

The electronic absorption and laser excited, wavelength resolved fluorescence spectra of the title cation have been observed in solid Ne matrix and vibrationally analysed. The vibrational structure of the excited B2A2??? state shows close similarity to the parent compound. The X2E??? ground state structure is strongly perturbed and irregular owing to a large Jahn-Teller distortion. The data are analysed in terms of a recently developed, sophisticated multimode Jahn-Teller theoretical model. We have generated the sym-C6Br3F3+ cations in solid Ne matrix and obtained their wavelength resolved emission and absorption spectra. T ground electronic X2E??? state exhibits an irregular and strongly perturbed vibrational structure, which can be successfully modeled using sophisticated multimode Jahn-Teller theory. ?? 1981.

Minimal nuclear energy density functional

NASA Astrophysics Data System (ADS)

Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi; Perez, Rodrigo Navarro; Schunck, Nicolas

2018-04-01

We present a minimal nuclear energy density functional (NEDF) called "SeaLL1" that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ɛr=0.022 fm and a standard deviation σr=0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body (NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body (NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. We identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.

Minimal nuclear energy density functional

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi

Inmore » this paper, we present a minimal nuclear energy density functional (NEDF) called “SeaLL1” that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ε r = 0.022 fm and a standard deviation σ r = 0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body ( NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body ( NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. Finally, we identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.« less

Minimal nuclear energy density functional

DOE PAGES

Bulgac, Aurel; Forbes, Michael McNeil; Jin, Shi; ...

2018-04-17

Inmore » this paper, we present a minimal nuclear energy density functional (NEDF) called “SeaLL1” that has the smallest number of possible phenomenological parameters to date. SeaLL1 is defined by seven significant phenomenological parameters, each related to a specific nuclear property. It describes the nuclear masses of even-even nuclei with a mean energy error of 0.97 MeV and a standard deviation of 1.46 MeV , two-neutron and two-proton separation energies with rms errors of 0.69 MeV and 0.59 MeV respectively, and the charge radii of 345 even-even nuclei with a mean error ε r = 0.022 fm and a standard deviation σ r = 0.025 fm . SeaLL1 incorporates constraints on the equation of state (EoS) of pure neutron matter from quantum Monte Carlo calculations with chiral effective field theory two-body ( NN ) interactions at the next-to-next-to-next-to leading order (N3LO) level and three-body ( NNN ) interactions at the next-to-next-to leading order (N2LO) level. Two of the seven parameters are related to the saturation density and the energy per particle of the homogeneous symmetric nuclear matter, one is related to the nuclear surface tension, two are related to the symmetry energy and its density dependence, one is related to the strength of the spin-orbit interaction, and one is the coupling constant of the pairing interaction. Finally, we identify additional phenomenological parameters that have little effect on ground-state properties but can be used to fine-tune features such as the Thomas-Reiche-Kuhn sum rule, the excitation energy of the giant dipole and Gamow-Teller resonances, the static dipole electric polarizability, and the neutron skin thickness.« less

Theoretical Study of the Jahn-Teller effect in CH3CN+ (X2E) and CD3CN+ (X2E): multimode spin-vibronic energy level calculations.

PubMed

Zhang, Shiyang; Mo, Yuxiang

2009-10-15

The spin-vibronic energy levels for CH(3)CN(+)(X(2)E) and CD(3)CN(+)(X(2)E) have been calculated using a diabatic model including multimode vibronic couplings and spin-orbit interaction without adjusting any parameter. The diabatic potential energy surfaces are represented by the Taylor expansions including linear, quadratic and bilinear vibronic coupling terms. The normal coordinates used in the Taylor expansion were expressed by the mass-weighted Cartesian coordinates. The adiabatic potential energy surfaces for CH(3)CN(+) and CD(3)CN(+) were calculated at the level of CASPT2/cc-pvtz, and the spin-orbit coupling constant was calculated at the level of MRCI/CAS/cc-pvtz. The spin-orbit energy splittings for the ground vibrational states of CH(3)CN(+)(X(2)E) and CD(3)CN(+)(X(2)E) are 20 and 16 cm(-1), respectively, which are resulted from the quenching of the spin-orbit coupling strength of 51 cm(-1). The calculated spin-vibronic levels are in good agreement with the experimental data. The calculation results show that the Jahn-Teller effects in CH(3)CN(+)(X(2)E) and CD(3)CN(+)(X(2)E) are essential to understand their spin-vibronic energy structure.

The Electronic Ground State of the Nitrate Radical: a Decade of Controversy

NASA Astrophysics Data System (ADS)

Stanton, John F.

2017-06-01

In the ten years since the traditional assignment of its degenerate stretching fundamental became controversial, a great deal of work - both theoretical and experimental - has been done on the NO_3 molecule. A brief review of these developments will be given, and results of very high-level calculations of the dispersed fluorescence and negative ion photoelectron spectra of this molecule will be presented together with the corresponding experimental results. In addition, the question of "what is next to do" on the ground state - from a theoretical point of view - will be addressed. Time permitting, some discussion will also be devoted to the strongly Jahn-Teller active ^2E^{''} (first excited) electronic state, where the level of understanding and agreement thus far obtained from experiment and theory is still at a rather primitive stage.

The entangled triplet pair state in acene and heteroacene materials

PubMed Central

Yong, Chaw Keong; Musser, Andrew J.; Bayliss, Sam L.; Lukman, Steven; Tamura, Hiroyuki; Bubnova, Olga; Hallani, Rawad K.; Meneau, Aurélie; Resel, Roland; Maruyama, Munetaka; Hotta, Shu; Herz, Laura M.; Beljonne, David; Anthony, John E.; Clark, Jenny; Sirringhaus, Henning

2017-01-01

Entanglement of states is one of the most surprising and counter-intuitive consequences of quantum mechanics, with potent applications in cryptography and computing. In organic materials, one particularly significant manifestation is the spin-entangled triplet-pair state, which mediates the spin-conserving fission of one spin-0 singlet exciton into two spin-1 triplet excitons. Despite long theoretical and experimental exploration, the nature of the triplet-pair state and inter-triplet interactions have proved elusive. Here we use a range of organic semiconductors that undergo singlet exciton fission to reveal the photophysical properties of entangled triplet-pair states. We find that the triplet pair is bound with respect to free triplets with an energy that is largely material independent (∼30 meV). During its lifetime, the component triplets behave cooperatively as a singlet and emit light through a Herzberg–Teller-type mechanism, resulting in vibronically structured photoluminescence. In photovoltaic blends, charge transfer can occur from the bound triplet pairs with >100% photon-to-charge conversion efficiency. PMID:28699637

Adult Competency Education Kit. Basic Skills in Speaking, Math, and Reading for Employment. Part N. ACE Competency Based Job Descriptions: #65--Typist I; #67--Grocery Checker; #68--File Clerk; #69--Receptionist; #70--Bank Teller; #71--Clerk, General Office.

ERIC Educational Resources Information Center

San Mateo County Office of Education, Redwood City, CA. Career Preparation Centers.

This eleventh of fifteen sets of Adult Competency Education (ACE) Competency Based Job Descriptions in the ACE kit contains job descriptions for Typist I, Grocery Checker, File Clerk, Receptionist; Bank Teller; and Clerk, General Office. Each begins with a fact sheet that includes this information: occupational title, D.O.T. code, ACE number,…

Toward New Horizons. Volume 10. Explosives and Terminal Ballistics

DTIC Science & Technology

1946-05-01

DuBridge Dr. W. J. Sweeney Dr. Pol Duwez Dr. H. S. Tsien Dr. G. Gamow Dr. G. E. Valley Dr. I. A. Getting Dr. F. L. Wattendorf Dr. L. P. Hammett Dr. F...can be calculated, if the heat quantities for the explosive are known, and some assumptions are made concerning the equation of the state of the

High-precision branching ratio measurement for the superallowed β+ emitter Ga62

NASA Astrophysics Data System (ADS)

Finlay, P.; Ball, G. C.; Leslie, J. R.; Svensson, C. E.; Towner, I. S.; Austin, R. A. E.; Bandyopadhyay, D.; Chaffey, A.; Chakrawarthy, R. S.; Garrett, P. E.; Grinyer, G. F.; Hackman, G.; Hyland, B.; Kanungo, R.; Leach, K. G.; Mattoon, C. M.; Morton, A. C.; Pearson, C. J.; Phillips, A. A.; Ressler, J. J.; Sarazin, F.; Savajols, H.; Schumaker, M. A.; Wong, J.

2008-08-01

A high-precision branching ratio measurement for the superallowed β+ decay of Ga62 was performed at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility. The 8π spectrometer, an array of 20 high-purity germanium detectors, was employed to detect the γ rays emitted following Gamow-Teller and nonanalog Fermi β+ decays of Ga62, and the SCEPTAR plastic scintillator array was used to detect the emitted β particles. Thirty γ rays were identified following Ga62 decay, establishing the superallowed branching ratio to be 99.858(8)%. Combined with the world-average half-life and a recent high-precision Q-value measurement for Ga62, this branching ratio yields an ft value of 3074.3±1.1 s, making Ga62 among the most precisely determined superallowed ft values. Comparison between the superallowed ft value determined in this work and the world-average corrected F tmacr value allows the large nuclear-structure-dependent correction for Ga62 decay to be experimentally determined from the CVC hypothesis to better than 7% of its own value, the most precise experimental determination for any superallowed emitter. These results provide a benchmark for the refinement of the theoretical description of isospin-symmetry breaking in A⩾62 superallowed decays.

Nuclear chiral axial currents and applications to few-nucleon systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baroni, Alessandro

This Thesis is divided into three main parts. The first part discusses basic aspects of chiral effective field theory and the formalism, based on time ordered perturbation theory, used to to derive the nuclear potentials and currents from the chiral Lagrangians. The second part deals with the actual derivation, up to one loop, of the two-nucleon potential and one- and two-nucleon weak axial charge and current. In both derivations ultraviolet divergences generated by loop corrections are isolated using dimensional regularization. The resulting axial current is finite and conserved in the chiral limit, while the axial charge requires renormalization. A completemore » set of contact terms for the axial charge up to the relevant order in the power counting is constructed. The third part of this Thesis discusses two applications: (i) the calculation of the Gamow-Teller matrix element of tritium, used to constrain the single low-energy constant entering the axial current; (ii) the calculation of neutrino-deuteron inclusive cross sections at low energies. These results have confirmed previous predictions obtained in phenomenological approaches. These latter studies have played an important role in the analysis and interpretation of experiments at the Sudbury Neutrino Observatory.« less

Unique first-forbidden β-decay rates for neutron-rich nickel isotopes in stellar environment

NASA Astrophysics Data System (ADS)

Nabi, Jameel-Un; Stoica, Sabin

2014-02-01

In astrophysical environments, allowed Gamow-Teller (GT) transitions are important, particularly for β-decay rates in presupernova evolution of massive stars, since they contribute to the fine-tuning of the lepton-to-baryon content of the stellar matter prior to and during the collapse of a heavy star. In environments where GT transitions are unfavored, first-forbidden transitions become important especially in medium heavy and heavy nuclei. Particularly in case of neutron-rich nuclei, first-forbidden transitions are favored primarily due to the phase-space amplification for these transitions. In this work the total β-decay half-lives and the unique first-forbidden (U1F) β-decay rates for a number of neutron-rich nickel isotopes, 72-78Ni, are calculated using the proton-neutron quasi-particle random phase approximation (pn-QRPA) theory in stellar environment for the first time. For the calculation of the β-decay half-lives both allowed and unique first-forbidden transitions were considered. Comparison of the total half-lives is made with measurements and other theoretical calculations where it was found that the pn-QRPA results are in better agreement with experiments and at the same time are suggestive of inclusion of rank 0 and rank 1 operators in first-forbidden rates for still better results.

Contribution of Jahn-Teller and charge transfer excitations to the photovoltaic effect of manganite/titanite heterojunctions

NASA Astrophysics Data System (ADS)

Ifland, Benedikt; Hoffmann, Joerg; Kressdorf, Birte; Roddatis, Vladimir; Seibt, Michael; Jooss, Christian

2017-06-01

The effect of correlation effects on photovoltaic energy conversion at manganite/titanite heterojunctions is investigated. As a model system we choose a heterostructure consisting of the small polaron absorber Pr0.66Ca0.34MnO3 (PCMO) epitaxially grown on single-crystalline Nb-doped SrTi0.998Nb0.002O3 (STNO) substrates. The high structural and chemical quality of the interfaces is proved by detailed characterization using high-resolution transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) studies. Spectrally resolved and temperature-dependent photovoltaic measurements show pronounced contributions of both the Jahn-Teller (JT) excitations and the charge transfer (CT) transitions to the photovoltaic effect at different photon energies. A linear temperature dependence of the open-circuit voltage for an excitation in the PCMO manganite is only observed below the charge-ordering temperature, indicating that the diffusion length of the photocarrier exceeds the size of the space charge region. The photovoltaic response is compared to that of a heterojunction of lightly doped Pr0.05Ca0.95MnO3 (CMO)/STNO, where the JT transition is absent. Here, significant contributions of the CT transition to the photovoltaic effect set in below the Neel temperature. We conclude that polaronic correlations and ordering effects are essentials for photovoltaic energy conversion in manganites.

Been there before? Examining "familiarity" as a moderator for discriminating between true and false intentions.

PubMed

Knieps, Melanie; Granhag, Pär A; Vrij, Aldert

2014-01-01

Prospection is thinking about possible future states of the world. Commitment to perform a future action-commonly referred to as intention-is a specific type of prospection. This knowledge is relevant when trying to assess whether a stated intention is a lie or the truth. An important observation is that thinking of, and committing to, future actions often evoke vivid and detailed mental images. One factor that affects how specific a person experiences these simulations is location-familiarity. The purpose of this study was to examine to what extent location-familiarity moderates how liars and truth tellers describe a mental image in an investigative interview. Liars were instructed to plan a criminal act and truth tellers were instructed to plan a non-criminal act. Before they could carry out these acts, the participants were intercepted and interviewed about the mental images they may have had experienced in this planning phase. Truth tellers told the truth whereas liars used a cover story to mask their criminal intentions. As predicted, the results showed that the truth tellers reported a mental image significantly more often than the liars. If a mental image was reported, the content of the descriptions did not differ between liars and truth tellers. In a post interview questionnaire, the participants rated the vividness (i.e., content and clarity) of their mental images. The ratings revealed that the truth tellers had experienced their mental images more vividly during the planning phase than the liars. In conclusion, this study indicates that both prototypical and specific representations play a role in prospection. Although location-familiarity did not moderate how liars and truth tellers describe their mental images of the future, this study allows some interesting insights into human future thinking. How these findings can be helpful for distinguishing between true and false intentions will be discussed.

Been there before? Examining “familiarity” as a moderator for discriminating between true and false intentions

PubMed Central

Knieps, Melanie; Granhag, Pär A.; Vrij, Aldert

2014-01-01

Prospection is thinking about possible future states of the world. Commitment to perform a future action—commonly referred to as intention—is a specific type of prospection. This knowledge is relevant when trying to assess whether a stated intention is a lie or the truth. An important observation is that thinking of, and committing to, future actions often evoke vivid and detailed mental images. One factor that affects how specific a person experiences these simulations is location-familiarity. The purpose of this study was to examine to what extent location-familiarity moderates how liars and truth tellers describe a mental image in an investigative interview. Liars were instructed to plan a criminal act and truth tellers were instructed to plan a non-criminal act. Before they could carry out these acts, the participants were intercepted and interviewed about the mental images they may have had experienced in this planning phase. Truth tellers told the truth whereas liars used a cover story to mask their criminal intentions. As predicted, the results showed that the truth tellers reported a mental image significantly more often than the liars. If a mental image was reported, the content of the descriptions did not differ between liars and truth tellers. In a post interview questionnaire, the participants rated the vividness (i.e., content and clarity) of their mental images. The ratings revealed that the truth tellers had experienced their mental images more vividly during the planning phase than the liars. In conclusion, this study indicates that both prototypical and specific representations play a role in prospection. Although location-familiarity did not moderate how liars and truth tellers describe their mental images of the future, this study allows some interesting insights into human future thinking. How these findings can be helpful for distinguishing between true and false intentions will be discussed. PMID:25071648

β-Decay half-lives and nuclear structure of exotic proton-rich waiting point nuclei under rp-process conditions

NASA Astrophysics Data System (ADS)

Nabi, Jameel-Un; Böyükata, Mahmut

2016-03-01

We investigate even-even nuclei in the A ∼ 70 mass region within the framework of the proton-neutron quasi-particle random phase approximation (pn-QRPA) and the interacting boson model-1 (IBM-1). Our work includes calculation of the energy spectra and the potential energy surfaces V (β , γ) of Zn, Ge, Se, Kr and Sr nuclei with the same proton and neutron number, N = Z. The parametrization of the IBM-1 Hamiltonian was performed for the calculation of the energy levels in the ground state bands. Geometric shape of the nuclei was predicted by plotting the potential energy surfaces V (β , γ) obtained from the IBM-1 Hamiltonian in the classical limit. The pn-QRPA model was later used to compute half-lives of the neutron-deficient nuclei which were found to be in very good agreement with the measured ones. The pn-QRPA model was also used to calculate the Gamow-Teller strength distributions and was found to be in decent agreement with the measured data. We further calculate the electron capture and positron decay rates for these N = Z waiting point (WP) nuclei in the stellar environment employing the pn-QRPA model. For the rp-process conditions, our total weak rates are within a factor two compared with the Skyrme HF +BCS +QRPA calculation. All calculated electron capture rates are comparable to the competing positron decay rates under rp-process conditions. Our study confirms the finding that electron capture rates form an integral part of the weak rates under rp-process conditions and should not be neglected in the nuclear network calculations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, S B; Sessler, A M

Edward Teller died on September 9, 2003 in Stanford, California at the age of 95. He was both one of the great theoretical physicists of the twentieth century and a leading figure in the development of nuclear weapons and broader defense advocacy. Teller's work in physics, spanning many decades of the twentieth century, includes some of the most fundamental insights in the quantum behaviors of molecules and their spectra, nuclei, surfaces, solid state and spin systems, and plasmas. In the defense arena, Teller is best known for his key insight that made thermonuclear weapons possible. Teller was both a greatmore » scientific collaborator and physics teacher at all levels, known for his openness, generosity, personal warmth, and powerful physical intuition. Many of his graduate students went on to illustrious careers.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, Swarnendu, E-mail: swarnendu.bhattacharyya@ch.tum.de; Domcke, Wolfgang, E-mail: wolfgang.domcke@ch.tum.de; Dai, Zuyang

A diabatic three-sheeted six-dimensional potential-energy surface has been constructed for the ground state and the lowest excited state of the PH{sub 3}{sup +} cation. Coupling terms of Jahn-Teller and pseudo-Jahn-Teller origin up to eighth order had to be included to describe the pronounced anharmonicity of the surface due to multiple conical intersections. The parameters of the diabatic Hamiltonian have been optimized by fitting the eigenvalues of the potential-energy matrix to ab initio data calculated at the CASSCF/MRCI level employing the correlation-consistent triple-ζ basis. The theoretical photoelectron spectrum of phosphine and the non-adiabatic nuclear dynamics of the phosphine cation have beenmore » computed by propagating nuclear wave packets with the multiconfiguration time-dependent Hartree method. The theoretical photoelectron bands obtained by Fourier transformation of the autocorrelation function agree well with the experimental results. It is shown that the ultrafast non-radiative decay dynamics of the first excited state of PH{sub 3}{sup +} is dominated by the exceptionally strong Jahn-Teller coupling of the asymmetric bending vibrational mode together with a hyperline of conical intersections with the electronic ground state induced by the umbrella mode. Time-dependent population probabilities have been computed for the three adiabatic electronic states. The non-adiabatic Jahn-Teller dynamics within the excited state takes place within ≈5 fs. Almost 80% of the excited-state population decay to the ground state within about 10 fs. The wave packets become highly complex and delocalized after 20 fs and no further significant transfer of electronic population seems to occur up to 100 fs propagation time.« less

Born-Oppenheimer and Renner-Teller Quantum Dynamics of CH(X(2)Π) + D((2)S) Reactions on Three CHD Potential Surfaces.

PubMed

Gamallo, Pablo; Akpinar, Sinan; Defazio, Paolo; Petrongolo, Carlo

2015-11-19

The quantum dynamics of three CH(X(2)Π) + D((2)S) reactions is studied by means of the coupled-channel time-dependent real-wavepacket (WP) and flux methods at collision energy Ecol ≤ 0.6 eV and on three potential energy surfaces (PESs): the Born-Oppenheimer (BO) ground PES X̃(3)A″ and the excited ones ã(1)A' and b̃(1)A″, coupled by nonadiabatic (NA) Renner-Teller (RT) effects. This three-state model is suitable for obtaining initial-state-resolved observables, is based on a complete analysis of the correlation diagram of the lowest electronic states of the CHD intermediate and of their NA interactions, and neglects the smaller coupling effects due to the asymptotic electronic angular momenta that become important in state-to-state dynamics. WPs are propagated on each PES at total angular momentum values J ≤ 70, with CH in the two lowest vibrational states v0 and in the ground rotational state j0 = 1. Reaction probabilities are obtained for three possible final products (f): (dP) CH decay and C((3)P) + HD(X(1)Σ(+)) formation that occurs on the uncoupled ground PES, (dD) CH decay and C((1)D) + HD(X(1)Σ(+)) formation that depends on the RT-coupled singlet species, and (ex) exchange to CD(X(2)Π) + H((2)S) available adiabatically from the X̃(3)A″ PES and nonadiabatically from ã(1)A' and b̃(1)A″. Observable cross sections σf,v0j0 and rate constants kf,v0j0 in the temperature range T = 100-2000 K are obtained for (dP), (dD), and (ex) channels. Comparing BO with RT probabilities, we show that NA effects are important at high J values for the (ex) channel at v0 = 1. Real time mechanisms on the three PESs show that RT couplings are opened after some time and clearly point out the formation of the product channels. Both cross sections and rate constants present the same sequence, for example σex,11 > σdP,01 ∼ σex,01 > σdP,11 ≫ σdD,11 ≫ σdD,01, and the CH vibrational excitation enhances the total removal CH+D reactivity by a factor of ∼1

Neutron and X-ray investigations of the Jahn–Teller switch in partially deuterated ammonium copper Tutton salt, (NH 4 ) 2 [Cu(H 2 O) 6 ](SO 4 ) 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jørgensen, Mads R. V.; Piccoli, Paula M. B.; Hathwar, Venkatesha R.

2017-01-31

The structural phase transition accompanied by a Jahn–Teller switch has been studied over a range of H/D ratios in (NH 4) 2[Cu(H 2O) 6](SO 4) 2(ACTS). In particular, single-crystal neutron diffraction investigations of crystals with deuteration in the range 50 to 82% are shown to be consistent with previous electron paramagnetic resonance (EPR) experiments exhibiting a phase boundary at 50% deuteration under ambient pressure. Polycrystalline samples show that the two phases can co-exist. In addition, single-crystal neutron and polycrystalline X-ray diffraction pressure experiments show a shift to lower pressure at 60% deuterationversusprevious measurements at 100% deuteration.

Resonance-state properties from a phase shift analysis with the S -matrix pole method and the effective-range method

NASA Astrophysics Data System (ADS)

Irgaziev, B. F.; Orlov, Yu. V.

2015-02-01

Asymptotic normalization coefficients (ANCs) are fundamental nuclear constants playing an important role in nuclear physics and astrophysics. We derive a new useful relationship between ANCs of the Gamow radial wave function and the renormalized (due to the Coulomb interaction) Coulomb-nuclear partial scattering amplitude. We use an analytical approximation in the form of a series for the nonresonant part of the phase shift which can be analytically continued to the point of an isolated resonance pole in the complex plane of the momentum. Earlier, this method which we call the S -matrix pole method was used by us to find the resonance pole energy. We find the corresponding fitting parameters for the 5He,5Li , and 16O concrete resonance states. Additionally, based on the theory of the effective range, we calculate the parameters of the p3 /2 and p1 /2 resonance states of the nuclei 5He and 5Li and compare them with the results obtained by the S -matrix pole method. ANC values are found which can be used to calculate the reaction rate through the 16O resonances which lie slightly above the threshold for the α 12C channel.

Foreword

NASA Astrophysics Data System (ADS)

Zhuk, A. I.; Ryabov, M. I.

This issue includes articles based on some plenary reports made during the 5th International Gamow Conference and the 15th Gamow conference-school. The Conference was devoted to a number of remarkable events:the 111 year Jubilee of George Gamow, one of the great physicists and cosmologists of the 20th century; the 150th anniversary of the Odessa I.I. Mechnikov National University and the Department of Astronomy; the 100th and 110th anniversaries of the Einstein's general and special relativity; the 50th anniversary of the discovery of cosmic microwave background (CMB) predicted by Gamow. The number 111 (three units!) represents the three major fundamental Gamow's achievements: alpha decay, the hot model of the universe and the prediction of CMB and deciphering of the genetic code. With 120 experts from 13 countries (Ukraine, Russia, Azerbaijan, Georgia, France, Italy, Switzerland, Poland, Egypt, Kazakhstan, Czech Republic, Belarus, USA) delivering 20 plenary talks, 113 contributed talks and 21 posters, both the Conference and the School were very successful. The main topics of the Conference were astrophysics, cosmology, gravity, high energy physics, radioastronomy, solar activity, solar system and astrobiology. Organizing Institutions: Odessa I.I. Mechnikov National University (Astronomical Observatory and Astronomy Department), Radio-Astronomical Institute of the NAS of Ukraine, Odessa Astronomical Society. The conference was held with the support of Ukrainian Astronomical Association, Euroasian Astronomical Society, Department of Physics and Astronomy of the NAS of Ukraine, South Scientific Center of the NAS of Ukraine.

Alpha-capture reaction rates for 22 Ne (α , n) via sub-Coulomb alpha-transfer and its effect on final abundances of s-process isotopes

NASA Astrophysics Data System (ADS)

Jayatissa, Heshani; Rogachev, Grigory; Koshchiy, Yevgeny; Goldberg, Vladilen; Hooker, Joshua; Hunt, Curtis; Magana, Cordero; Roeder, Brian; Saastamoinen, Antti; Spiridon, Alexandria; Upadhyayula, Sriteja; Trippella, Oscar

2017-09-01

The 22 Ne (α , n) reaction is a very important neutron source reaction for the slow neutron capture process (s-process) in asymptotic giant branch stars. These direct measurements are very difficult to carry out at the energy regimes of interest for astrophysics (Gamow energies) due to the extremely small reaction cross section. The large uncertainties introduced when extrapolating direct measurements at high energies down to the Gamow energies can be overcome by measuring the Asymptotic Normalization Coefficients (ANC) of the relevant states using α-transfer reactions at sub-Coulomb energies to reduce the optical model dependence. The study of the 22Ne(6Li,d) and 22Ne(7Li,t) reaction was carried out at the Cyclotron Institute at Texas A&M University. The α-ANC measurements for the near α-threshold resonances of 26Mg provide constraints for the 22Ne(α,n) reaction rate. The effect of this reaction rate on the final abundances of the s-process isotopes will be discussed.

Investigation of deformation effects on the decay properties of 12 C + α Cluster states in 16O

NASA Astrophysics Data System (ADS)

Soylu, A.; Koyuncu, F.; Coban, A.; Bayrak, O.; Freer, M.

2018-04-01

We have analyzed the elastic scattering angular distributions data of the α +12C reaction over a wide energy range (Elab = 28 . 2 to 35.5 MeV) within the framework of the Optical Model formalism. A double folding (DF) type real potential was used with a phenomenological Woods-Saxon-squared (WS2) type imaginary potential. Good agreement between the calculations and experimental data was obtained. By using the real DF potential we have calculated the properties of the α-cluster states in 16O by using the Gamow code as well as the α-decay widths by using the WKB method. We implemented a 12C + α cluster framework for the calculation of the excitation energies and decay widths of 16O as a function of the orientation of the planar 12C nucleus with respect to the α-particle. These calculations showed strong sensitivity of the widths and excitation energies to the orientation. Branching ratios were also calculated and though less sensitive to the 12C orientation, it was found that 12Cgs + α structure, with the α-particle orbiting the 12C in its ground state, is dominant. This work demonstrates that deformation, and the orientation, of 12C plays a crucial role in the understanding of the nature of the α-cluster states in 16O.

Energy Dispersive XAFS: Characterization of Electronically Excited States of Copper(I) Complexes

PubMed Central

2013-01-01

Energy dispersive X-ray absorption spectroscopy (ED-XAS), in which the whole XAS spectrum is acquired simultaneously, has been applied to reduce the real-time for acquisition of spectra of photoinduced excited states by using a germanium microstrip detector gated around one X-ray bunch of the ESRF (100 ps). Cu K-edge XAS was used to investigate the MLCT states of [Cu(dmp)2]+ (dmp =2,9-dimethyl-1,10-phenanthroline) and [Cu(dbtmp)2]+ (dbtmp =2,9-di-n-butyl-3,4,7,8-tetramethyl-1,10-phenanthroline) with the excited states created by excitation at 450 nm (10 Hz). The decay of the longer lived complex with bulky ligands, was monitored for up to 100 ns. DFT calculations of the longer lived MLCT excited state of [Cu(dbp)2]+ (dbp =2,9-di-n-butyl-1,10-phenanthroline) with the bulkier diimine ligands, indicated that the excited state behaves as a Jahn–Teller distorted Cu(II) site, with the interligand dihedral angle changing from 83 to 60° as the tetrahedral coordination geometry flattens and a reduction in the Cu–N distance of 0.03 Å. PMID:23718738

Modulation of Jahn-Teller effect on magnetization and spontaneous electric polarization of CuFeO2

NASA Astrophysics Data System (ADS)

Xiao, Guiling; Xia, Zhengcai; Wei, Meng; Huang, Sha; Shi, Liran; Zhang, Xiaoxing; Wu, Huan; Yang, Feng; Song, Yujie; Ouyang, Zhongwen

2018-03-01

CuFe0.99Mn0.01O2 and CuFe0.99Co0.01O2 single crystal samples are grown by a floating zone technique and their magnetization and spontaneous electric polarization have been investigated. Similarly with pure CuFeO2, an obviously anisotropic magnetization and spontaneous electric polarization were observed in the both doped samples, and their phase transition critical fields and temperatures are directly doping ion dependent. Considering the different d-shell configuration and ionic size between Mn3+, Co3+ and Fe3+ ions, in which the Mn3+ ion with Jahn-Teller (J-T) effect has different distortion on the geometry frustration from both of Fe3+ and Co3+ ion. Since for Mn3+ ion, the orbital splitting results from the low-symmetry J-T distortion in a crystal-field environment leads to a distorted MnO6 octahedron, which different from undistorted FeO6 and CoO6 octahedrons. The strain between distorted and undistorted octahedrons produces different effects on the spin reorientation transition and spontaneous electric polarization. Although the pure CuFeO2 has a very strong and robust frustration, the presence of the strain due to the random distribution of distorted MnO6 octahedron and undistorted CoO6 (FeO6) octahedrons leads to its spin reorientation transitions and spontaneous electric polarization different from CuFeO2.

Thermodynamics properties study of diatomic molecules with q-deformed modified Poschl-Teller plus Manning Rosen non-central potential in D dimensions using SUSYQM approach

NASA Astrophysics Data System (ADS)

Suparmi, A.; Cari, C.; Pratiwi, B. N.

2016-04-01

D-dimensional Dirac equation of q-deformed modified Poschl-Teller plus Manning Rosen non-central potential was solved using supersymmetric quantum mechanics (SUSY QM). The relativistic energy spectra were analyzed by using SUSY QM and shape invariant properties from radial part of D dimensional Dirac equation and the angular quantum numbers were obtained from angular part of D dimensional Dirac equation. The SUSY operators was used to generate the D dimensional relativistic wave functions both for radial and angular parts. In the non-relativistic limit, the relativistic energy equation was reduced to the non-relativistic energy. In the classical limit, the partition function of vibrational, the specific heat of vibrational, and the mean energy of vibrational of some diatomic molecules were calculated from the equation of non-relativistic energy with the help of error function and Mat-lab 2011.

Modified automatic teller machine prototype for older adults: a case study of participative approach to inclusive design.

PubMed

Chan, Chetwyn C H; Wong, Alex W K; Lee, Tatia M C; Chi, Iris

2009-03-01

The goal of this study was to enhance an existing automated teller machine (ATM) human-machine interface in order to accommodate the needs of older adults. Older adults were involved in the design and field test of the modified ATM prototype. The design of the user interface and functionality took the cognitive and physical abilities of older adults into account. The modified ATM system included only "cash withdrawal" and "transfer" functions based on the task demands and needs for services of older adults. One hundred and forty-one older adults (aged 60 or above) participated in the field test by operating modified or existing ATM systems. Those who operated the modified system were found to have significantly higher success rates than those who operated the existing system. The enhancement was most significant among older adults who had lower ATM-related abilities, a lower level of education, and no prior experience of using ATMs. This study demonstrates the usefulness of using a universal design and participatory approach to modify the existing ATM system for use by older adults. However, it also leads to a reduction in functionality of the enhanced system. Future studies should explore ways to develop a universal design ATM system which can satisfy the abilities and needs of all users in the entire population.

Hydrothermal Synthesis and Characterization of Novel Brackebuschite-Type Transition Metal Vanadates: Ba 2 M(VO 4 ) 2 (OH), M = V 3+ , Mn 3+ , and Fe 3+ , with Interesting Jahn–Teller and Spin-Liquid Behavior

DOE PAGES

Sanjeewa, Liurukara D.; McGuire, Michael A.; Garlea, Vasile O.; ...

2015-07-08

In a new series of transition metal vanadates, namely, Ba 2M(VO 4) 2(OH) (M = V 3+, Mn 3+, and Fe 3+), was synthesized as large single crystals hydrothermally in 5 M NaOH solution at 580 °C and 1 kbar. This new series of compounds is structurally reminiscent of the brackebuschite mineral type. The structure of Ba 2V(VO 4) 2(OH) is monoclinic in space group P2 1/m, a = 7.8783(2) Å, b = 6.1369(1) Å, c = 9.1836(2) Å, β = 113.07(3)°, V = 408.51(2) Å 3. Moreover, the other structures are similar and consist of one-dimensional trans edge-shared distortedmore » octahedral chains running along the b-axis. The vanadate groups bridge across edges of their tetrahedra. Structural analysis of the Ba 2Mn(VO 4) 2(OH) analogue yielded a new understanding of the Jahn–Teller effect in this structure type. Raman and infrared spectra were investigated to observe the fundamental vanadate and hydroxide vibrational modes. Finally, single-crystal temperature-dependent magnetic studies on Ba 2V(VO 4) 2(OH) reveal a broad feature over a wide temperature range with maximum at ~100 K indicating that an energy gap could exist between the antiferromagnetic singlet ground state and excited triplet states, making it potentially of interest for quantum magnetism studies.« less

New quasibound states of the compound nucleus in α -particle capture by the nucleus

NASA Astrophysics Data System (ADS)

Maydanyuk, Sergei P.; Zhang, Peng-Ming; Zou, Li-Ping

2017-07-01

We generalize the theory of nuclear decay and capture of Gamow that is based on tunneling through the barrier and internal oscillations inside the nucleus. In our formalism an additional factor is obtained, which describes distribution of the wave function of the the α particle inside the nuclear region. We discover new most stable states (called quasibound states) of the compound nucleus (CN) formed during the capture of α particle by the nucleus. With a simple example, we explain why these states cannot appear in traditional calculations of the α capture cross sections based on monotonic penetrabilities of a barrier, but they appear in a complete description of the evolution of the CN. Our result is obtained by a complete description of the CN evolution, which has the advantages of (1) a clear picture of the formation of the CN and its disintegration, (2) a detailed quantum description of the CN, (3) tests of the calculated amplitudes based on quantum mechanics (not realized in other approaches), and (4) high accuracy of calculations (not achieved in other approaches). These peculiarities are shown with the capture reaction of α +44Ca . We predict quasibound energy levels and determine fusion probabilities for this reaction. The difference between our approach and theory of quasistationary states with complex energies applied for the α capture is also discussed. We show (1) that theory does not provide calculations for the cross section of α capture (according to modern models of the α capture), in contrast with our formalism, and (2) these two approaches describe different states of the α capture (for the same α -nucleus potential).

α-ScVSe2O8, β-ScVSe2O8, and ScVTe2O8: new quaternary mixed metal oxides composed of only second-order Jahn-Teller distortive cations.

PubMed

Kim, Yeong Hun; Lee, Dong Woo; Ok, Kang Min

2013-10-07

Three new quaternary scandium vanadium selenium/tellurium oxides, α-ScVSe2O8, β-ScVSe2O8, and ScVTe2O8 have been synthesized through hydrothermal and standard solid-state reactions. Although all three reported materials are stoichiometrically similar, they exhibit different crystal structures: α-ScVSe2O8 has a three-dimensional framework structure consisting of ScO6, VO6, and SeO3 groups. β-ScVSe2O8 reveals another three-dimensional framework composed of ScO7, VO5, and SeO3 polyhedra. ScVTe2O8 shows a layered structure with ScO6, VO4, and TeO4 polyhedra. Interestingly, the constituent cations, that is, Sc(3+), V(5+), Se(4+), and Te(4+) are all in a distorted coordination environment attributable to second-order Jahn-Teller (SOJT) effects. Complete characterizations including infrared spectroscopy, elemental analyses, thermal analyses, dipole moment calculation, and the magnitudes of out-of-center distortions for the compounds are reported. Transformation reactions suggest that α-ScVSe2O8 may change to β-ScVSe2O8, and then to Sc2(SeO3)3·H2O under hydrothermal conditions.

Spin-state blockade in Te6+-substituted electron-doped LaCoO3

NASA Astrophysics Data System (ADS)

Tomiyasu, Keisuke; Koyama, Shun-Ichi; Watahiki, Masanori; Sato, Mika; Nishihara, Kazuki; Onodera, Mitsugi; Iwasa, Kazuaki; Nojima, Tsutomu; Yamasaki, Yuuichi; Nakao, Hironori; Murakami, Youichi

2015-03-01

Perovskite-type LaCoO3 (Co3+: d6) is a rare inorganic material with sensitive and characteristic responses among low, intermediate, and high spin states. For example, in insulating nonmagnetic low-spin states below about 20 K, light hole doping (Ni substitution) induces much larger magnetization than expected; over net 10μB/hole (5μB/Ni) for 1μB/hole (1μB/Ni), in which the nearly isolated dopants locally change the surrounding Co low-spin states to magnetic ones and form spin molecules with larger total spin. Further, the former is isotropic, whereas the latter exhibits characteristic anisotropy probably because of Jahn-Teller distortion. In contrast, for electron doping, relatively insensitive spin-state responses were reported, as in LaCo(Ti4+) O3, but are not clarified, and are somewhat controversial. Here, we present macroscopic measurement data of another electron-doped system LaCo(Te6+) O3 and discuss the spin-state responses. This study was financially supported by Grants-in-Aid for Young Scientists (B) (No. 22740209 and 26800174) from the MEXT of Japan.

Comment on 'Origin of light-induced states in intense laser fields and their observability in photoelectron spectra'

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stroe, Marius; Boca, Malina

2005-01-01

We report discrepancies between the results presented in Fig. 1 of a recent paper of Yasuike and Someda [Phys. Rev. A 66, 053410 (2002)] and our independent calculation. At the frequency {omega}=0.55 a.u., we find that the state of the one-dimensional modified Poeschl-Teller potential, described by the authors as light induced and originating from a shadow of the field-free ground state, is in fact physical for {alpha}{sub 0}<10 a.u. and its origin is the zero-energy antibound state of the bare potential. For {omega}=0.45 a.u., we also find differences in one of the presented quasienergy trajectories in the low {alpha}{sub 0}more » region ({alpha}{sub 0}<0.4 a.u.), but we confirm the starting point at E=-0.5 a.u. for both quasienergies, as found by Yasuike and Someda.« less

Yura-George's world line

NASA Astrophysics Data System (ADS)

Gamov, I. L.

It is quite interesting and flattering for an economist to publish a paper in such a prominent astronomical journal. And taking into account the fact that the author is a relative of the great cosmologist of the 20th century does not diminish but, vice versa, increases the piquancy of the appearance of this article. You may agree, dear readers, that it is fairly difficult to avoid a temptation of addressing you on behalf of numerous admirers of George Gamow's talent, as well as of supporters of the Gamow Foundation of Moldova. Frankly speaking, I cannot get rid of a feeling that George Gamow himself, through some genetic "channels" known to him alone, is pushing me to tell about him, for he was famous for all kinds of tricks.

Off-Centre Effects in the Triplet Relaxed Excited State of Ga+ Centres in CsBr:Ga Crystal

NASA Astrophysics Data System (ADS)

Kalder, K.; Korrovits, V.; Nagirnyi, V.; Stolovits, A.; Zazubovich, S.; Babin, V.

1997-06-01

Spectra, polarization and decay kinetics of the triplet and singlet emission of Ga+ centres in CsBr:Ga crystals have been studied in the temperature range of 0.1 to 400 K. It has been found that the triplet AX and AT emission bands coincide. Two slow components have been observed in the decay kinetics of each emission at T < 1.5 K and explained by the tunnel splitting of the metastable minima of the corresponding triplet relaxed excited state. It points to the off-centre displacement of a Ga+ ion from a crystal lattice site both in the tetragonal (T) and in the trigonal (X) Jahn-Teller minima.

Theory of optical transitions in π-conjugated macrocycles

NASA Astrophysics Data System (ADS)

Marcus, Max; Coonjobeeharry, Jaymee; Barford, William

2016-04-01

We describe a theoretical and computational investigation of the optical properties of π-conjugated macrocycles. Since the low-energy excitations of these systems are Frenkel excitons that couple to high-frequency dispersionless phonons, we employ the quantized Frenkel-Holstein model and solve it via the density matrix renormalization group (DMRG) method. First we consider optical emission from perfectly circular systems. Owing to optical selection rules, such systems radiate via two mechanisms: (i) within the Condon approximation, by thermally induced emission from the optically allowed j = ± 1 states and (ii) beyond the Condon approximation, by emission from the j = 0 state via coupling with a totally non-symmetric phonon (namely, the Herzberg-Teller effect). Using perturbation theory, we derive an expression for the Herzberg-Teller correction and show via DMRG calculations that this expression soon fails as ħ ω/J and the size of the macrocycle increase. Next, we consider the role of broken symmetry caused by torsional disorder. In this case the quantum number j no longer labels eigenstates of angular momentum, but instead labels localized local exciton groundstates (LEGSs) or quasi-extended states (QEESs). As for linear polymers, LEGSs define chromophores, with the higher energy QEESs being extended over numerous LEGSs. Within the Condon approximation (i.e., neglecting the Herzberg-Teller correction) we show that increased disorder increases the emissive optical intensity, because all the LEGSs are optically active. We next consider the combined role of broken symmetry and curvature, by explicitly evaluating the Herzberg-Teller correction in disordered systems via the DMRG method. The Herzberg-Teller correction is most evident in the emission intensity ratio, I00/I01. In the Condon approximation I00/I01 is a constant function of curvature, whereas in practice it vanishes for closed rings and only approaches a constant in the limit of vanishing curvature. We

High precision analytical description of the allowed β spectrum shape

NASA Astrophysics Data System (ADS)

Hayen, Leendert; Severijns, Nathal; Bodek, Kazimierz; Rozpedzik, Dagmara; Mougeot, Xavier

2018-01-01

A fully analytical description of the allowed β spectrum shape is given in view of ongoing and planned measurements. Its study forms an invaluable tool in the search for physics beyond the standard electroweak model and the weak magnetism recoil term. Contributions stemming from finite size corrections, mass effects, and radiative corrections are reviewed. Particular focus is placed on atomic and chemical effects, where the existing description is extended and analytically provided. The effects of QCD-induced recoil terms are discussed, and cross-checks were performed for different theoretical formalisms. Special attention was given to a comparison of the treatment of nuclear structure effects in different formalisms. Corrections were derived for both Fermi and Gamow-Teller transitions, and methods of analytical evaluation thoroughly discussed. In its integrated form, calculated f values were in agreement with the most precise numerical results within the aimed for precision. The need for an accurate evaluation of weak magnetism contributions was stressed, and the possible significance of the oft-neglected induced pseudoscalar interaction was noted. Together with improved atomic corrections, an analytical description was presented of the allowed β spectrum shape accurate to a few parts in 10-4 down to 1 keV for low to medium Z nuclei, thereby extending the work by previous authors by nearly an order of magnitude.

Overview of the Calcium-45 Beta Spectrum Measurement at Los Alamos National Laboratory

NASA Astrophysics Data System (ADS)

Royse, Camen; Nab/UNCB Teams Collaboration

2017-09-01

One smoking gun of BSM physics would be the observation of a non-zero Fierz interference term, a feature in the beta spectrum produced by scalar and tensor couplings. Calcium-45 is an almost ideal candidate with which to search for a Fierz term. It is a pure beta emitter with a low endpoint of 256 keV and a simple decay scheme, with a 7 / 2 - -> 7 / 2 - g.s. to g.s. branching ratio of 99.9981(11)%. Isospin selection rules ensure the decay is greater than about 98.5% pure Gamow-Teller and the integrated effect of the weak magnetism over the entire spectrum is expected to be only 0.13%. An experiment designed to precisely measure the beta spectrum of Ca-45 has been run over the past two summers at Los Alamos National Laboratory. The experiment is composed of a 4 π-capture magnetic spectrometer between two segmented arrays of hexagonal silicon detectors (similar to the Nab experiment), a helium gas cooling system, front end electronics and amplifiers, and a data acquisition system which synchronizes the timing from the signals coming from both detector arrays. Data is analyzed to account for the pile-up of signals and other physical and calibration factors. An overview of the design and execution of the experiment as divided into the above topics will be presented.

Nuclear structure and weak rates of heavy waiting point nuclei under rp-process conditions

NASA Astrophysics Data System (ADS)

Nabi, Jameel-Un; Böyükata, Mahmut

2017-01-01

The structure and the weak interaction mediated rates of the heavy waiting point (WP) nuclei 80Zr, 84Mo, 88Ru, 92Pd and 96Cd along N = Z line were studied within the interacting boson model-1 (IBM-1) and the proton-neutron quasi-particle random phase approximation (pn-QRPA). The energy levels of the N = Z WP nuclei were calculated by fitting the essential parameters of IBM-1 Hamiltonian and their geometric shapes were predicted by plotting potential energy surfaces (PESs). Half-lives, continuum electron capture rates, positron decay rates, electron capture cross sections of WP nuclei, energy rates of β-delayed protons and their emission probabilities were later calculated using the pn-QRPA. The calculated Gamow-Teller strength distributions were compared with previous calculation. We present positron decay and continuum electron capture rates on these WP nuclei under rp-process conditions using the same model. For the rp-process conditions, the calculated total weak rates are twice the Skyrme HF+BCS+QRPA rates for 80Zr. For remaining nuclei the two calculations compare well. The electron capture rates are significant and compete well with the corresponding positron decay rates under rp-process conditions. The finding of the present study supports that electron capture rates form an integral part of the weak rates under rp-process conditions and has an important role for the nuclear model calculations.

The ``Folk Theorem'' on effective field theory: How does it fare in nuclear physics?

NASA Astrophysics Data System (ADS)

Rho, Mannque

2017-10-01

This is a brief history of what I consider as very important, some of which truly seminal, contributions made by young Korean nuclear theorists, mostly graduate students working on PhD thesis in 1990s and early 2000s, to nuclear effective field theory, nowadays heralded as the first-principle approach to nuclear physics. The theoretical framework employed is an effective field theory anchored on a single scale-invariant hidden local symmetric Lagrangian constructed in the spirit of Weinberg's "Folk Theorem" on effective field theory. The problems addressed are the high-precision calculations on the thermal np capture, the solar pp fusion process, the solar hep process — John Bahcall's challenge to nuclear theorists — and the quenching of g A in giant Gamow-Teller resonances and the whopping enhancement of first-forbidden beta transitions relevant in astrophysical processes. Extending adventurously the strategy to a wild uncharted domain in which a systematic implementation of the "theorem" is far from obvious, the same effective Lagrangian is applied to the structure of compact stars. A surprising, unexpected, result on the properties of massive stars, totally different from what has been obtained up to day in the literature, is predicted, such as the precocious onset of conformal sound velocity together with a hint for the possible emergence in dense matter of hidden symmetries such as scale symmetry and hidden local symmetry.

Study of Various Types of Resonances within the Phonon Damping Model

NASA Astrophysics Data System (ADS)

Dang, Nguyen Dinh

2001-10-01

The main successes of the Phonon Damping Model (PDM)(N. Dinh Dang and A. Arima, Phys. Rev. Lett. 80), 4145 (1998); Nucl. Phys. A 636, 427 (1998); N. Dinh Dang, K. Tanabe, and A. Arima, Phys. Rev. C 58, 3374 (1998). are presented in the description of: 1) the giant dipole resonance (GDR) in highly excited nuclei, 2) the double giant dipole resonance (DGDR) and multiple phonon resonances, 3) the Gamow-Teller resonance (GTR), and 4) the damping of pygmy dipole resonance (PDR) in neutron-rich nuclei. The analyses of results of numerical calculations are discussed in comparison with the experimental systematics on i) the width and the shape of the GDR at finite temperature ^1,(N. Dinh Dang et al., Phys. Rev. C 61), 027302 (2000). and angular momentum(N. Dinh Dang, Nucl. Phys. A 687), 261c (2001). for tin isotopes , ii) the electromagnetic cross sections of DGDR for ^136Xe and ^208Pb on a lead target at relativistic energies(N. Dinh Dang, V. Kim Au, and A. Arima, Phys. Rev. Lett. 85), 1827 (2000)., iii) the strength function of GTR(N. Dinh Dang, T. Suzuki, and A. Arima, Preprint RIKEN-AF-NF 377 (2000), submitted.), and iv) the PDR in oxygen and calcium isotopes(N. Dinh Dang et al., Phys. Rev. C 63), 044302 (2001)..

First spin-parity constraint of the 306 keV resonance in Cl 35 for nova nucleosynthesis

DOE PAGES

Chipps, K. A.; Rutgers Univ., New Brunswick, NJ; Pain, S. D.; ...

2017-04-28

Something of particular interest in astrophysics is the 34 S ( p , γ ) 35 Cl reaction, which serves as a stepping stone in thermonuclear runaway reaction chains during a nova explosion. Although the isotopes involved are all stable, the reaction rate of this significant step is not well known, due to a lack of experimental spectroscopic information on states within the Gamow window above the proton separation threshold of 35 Cl . Furthermore, measurements of level spins and parities provide input for the calculation of resonance strengths, which ultimately determine the astrophysical reaction rate of the 34 Smore » ( p , γ ) 35 Cl proton capture reaction. By performing the 37 Cl ( p , t ) 35 Cl reaction in normal kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, we have conducted a study of the region of astrophysical interest in 35 Cl , and have made the first-ever constraint on the spin and parity assignment for a level at 6677 ± 15 keV ( E r = 306 keV), inside the Gamow window for novae.« less

First spin-parity constraint of the 306 keV resonance in 35Cl for nova nucleosynthesis

NASA Astrophysics Data System (ADS)

Chipps, K. A.; Pain, S. D.; Kozub, R. L.; Bardayan, D. W.; Cizewski, J. A.; Chae, K. Y.; Liang, J. F.; Matei, C.; Moazen, B. H.; Nesaraja, C. D.; O'Malley, P. D.; Peters, W. A.; Pittman, S. T.; Schmitt, K. T.; Smith, M. S.

2017-04-01

Of particular interest in astrophysics is the 34S(p ,γ )35Cl reaction, which serves as a stepping stone in thermonuclear runaway reaction chains during a nova explosion. Though the isotopes involved are all stable, the reaction rate of this significant step is not well known, due to a lack of experimental spectroscopic information on states within the Gamow window above the proton separation threshold of 35Cl. Measurements of level spins and parities provide input for the calculation of resonance strengths, which ultimately determine the astrophysical reaction rate of the 34S(p ,γ )35Cl proton capture reaction. By performing the 37Cl(p ,t )35Cl reaction in normal kinematics at the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory, we have conducted a study of the region of astrophysical interest in 35Cl, and have made the first-ever constraint on the spin and parity assignment for a level at 6677 ±15 keV (Er=306 keV), inside the Gamow window for novae.

Proceedings of US-Latin American Workshop on Molecular and Materials Sciences: Theoretical and Computational Aspects Held in Gainesville, Florida on 10-12 March 1993

DTIC Science & Technology

1994-08-09

City Josd Rdamier and R. Iterative Bogoliubov Transformations and Applications Jauregui Inst. de Fisica , Cuernavaca, Meiico Peter J. Reynolds Quantum...University, Provo, UT 84602 J. R•camier Instituto de Fisica , UNAM, Cuernavaca, Mor., MWxico Gamow states are solutions to the Schr6dinger equation with a...Coutinho Departamento de FAsica do UFPE 50732-910 Recife, PE, Brazil and Jnstituto de Fisica da USP, Czp 20516 01498-970 Sdo Paulo, SP, Brasil The

Renner-Teller quantum dynamics of NH(a(1)Delta) + H reactions on the NH(2) A(2)A(1) and X(2)B(1) coupled surfaces.

PubMed

Defazio, P; Gamallo, P; González, M; Petrongolo, C

2010-09-16

Four reactions NH(a1Delta) + H′(2S) are investigated by the quantum mechanical real wavepacket method, taking into account nonadiabatic Renner-Teller (RT) and rovibronic Coriolis couplings between the involved states. We consider depletion (d) to N(2D) + H2(X1Sigmag+), exchange (e) to NH′(a1Delta) + H(2S), quenching (q) to NH(X3Sigma-) + H′(2S), and exchange-quenching (eq) to NH′(X3Sigma-) + H(2S). We extend our RT theory to a general AB + C collision using a geometry-dependent but very simple and empirical RT matrix element. Reaction probabilities, cross sections, and rate constants are presented, and RT results are compared with Born-Oppenheimer (BO), experimental, and semiclassical data. The nonadiabatic couplings open two new channels, (q) and (eq), and increase the (d) and (e) reactivity with respect to the BO one, when NH(a1Delta) is rotationally excited. In this case, the quantum cross sections are larger than the semiclassical ones at low collision energies. The calculated rate constants at 300 K are k(d) = 3.06, k(e) = 3.32, k(q) = 1.44, and k(eq) = 1.70 in 10(-11) cm3 s(-1) compared with the measured values k(d) = (3.2 =/- 1.7), k(q + eq) = (1.7 +/- 0.3), and k(total) = (4.8 +/- 1.7). The theoretical depletion rate is thus in good agreement with the experimental value, but the quenching and total rates are overestimated, because the present RT couplings are too large. This discrepancy is probably due to our simple and empirical RT matrix element.

Specific features of the structural and magnetic states of a Zn1 - x Ni x Se crystal ( x = 0.0025) at low temperatures

NASA Astrophysics Data System (ADS)

Dubinin, S. F.; Sokolov, V. I.; Parkhomenko, V. D.; Teploukhov, S. G.; Gruzdev, N. B.

2008-12-01

The magnetic state and the structure of a Zn1 - x Ni x Se ( x = 0.0025) bulk crystal were studied at low temperatures. It is revealed that the magnetic and crystal structures below T ≅ 15 K are dependent on the cooling rate of this dilute semiconductor. For example, on fast cooling to 4.2 K, about 10% hexagonal ferromagnetic phase is formed in the crystal. During heating, the phase disappears at T ≅ 15 K. The results obtained are discussed with allowance for the specific features of the Jahn-Teller distortions in this compound.

JOZSO, a computer code for calculating broad neutron resonances in phenomenological nuclear potentials

NASA Astrophysics Data System (ADS)

Baran, Á.; Noszály, Cs.; Vertse, T.

2018-07-01

A renewed version of the computer code GAMOW (Vertse et al., 1982) is given in which the difficulties in calculating broad neutron resonances are amended. New types of phenomenological neutron potentials with strict finite range are built in. Landscape of the S-matrix can be generated on a given domain of the complex wave number plane and S-matrix poles in the domain are localized. Normalized Gamow wave functions and trajectories of given poles can be calculated optionally.

Constraining Nuclear Weak Interactions in Astrophysics and New Many-Core Algorithms for Neuroevolution

NASA Astrophysics Data System (ADS)

Sullivan, Christopher James

Weak interactions involving atomic nuclei are critical components in a broad range of as- trophysical phenomenon. As allowed Gamow-Teller transitions are the primary path through which weak interactions in nuclei operate in astrophysical contexts, the constraint of these nuclear transitions is an important goal of nuclear astrophysics. In this work, the charged current nuclear weak interaction known as electron capture is studied in the context of stellar core-collapse supernovae (CCSNe). Specifically, the sensitivity of the core-collapse and early post-bounce phases of CCSNe to nuclear electron capture rates are examined. Electron capture rates are adjusted by factors consistent with uncer- tainties indicated by comparing theoretical rates to those deduced from charge-exchange and beta-decay measurements. With the aide of such sensitivity studies, the diverse role of electron capture on thousands of nuclear species is constrained to a few tens of nuclei near N 50 and A 80 which dictate the primary response of CCSNe to nuclear electron capture. As electron capture is shown to be a leading order uncertainty during the core-collapse phase of CCSNe, future experimental and theoretical efforts should seek to constrain the rates of nuclei in this region. Furthermore, neutral current neutrino-nuclear interactions in the tens-of-MeV energy range are important in a variety of astrophysical environments including core-collapse super- novae as well as in the synthesis of some of the solar systems rarest elements. Estimates for inelastic neutrino scattering on nuclei are also important for neutrino detector construction aimed at the detection of astrophysical neutrinos. Due to the small cross sections involved, direct measurements are rare and have only been performed on a few nuclei. For this rea- son, indirect measurements provide a unique opportunity to constrain the nuclear transition strength needed to infer inelastic neutrino-nucleus cross sections. Herein the (6Li, 6

Nonadiabatic dynamics of O({sup 1}D) + N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}){yields}O({sup 3}P) + N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}) on three coupled potential surfaces: Symmetry, Coriolis, spin-orbit, and Renner-Teller effects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Defazio, Paolo; Gamallo, Pablo; Petrongolo, Carlo

2012-02-07

We present the spin-orbit (SO) and Renner-Teller (RT) quantum dynamics of the spin-forbidden quenching O({sup 1}D) + N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}){yields}O({sup 3}P) + N{sub 2}(X{sup 1}{Sigma}{sub g}{sup +}) on the N{sub 2}O X-tilde{sup 1}A{sup '}, a-tilde{sup 3}A', and b-tilde{sup 3}A{sup '} coupled PESs. We use the permutation-inversion symmetry, propagate coupled-channel (CC) real wavepackets, and compute initial-state-resolved probabilities and cross sections {sigma}{sub j0} for the ground vibrational and the first two rotational states of N{sub 2}, j{sub 0}= 0 and 1. Labeling symmetry angular states by j and K, we report selection rules for j and for the minimum Kmore » value associated with any electronic state, showing that a-tilde{sup 3}A' is uncoupled in the centrifugal-sudden (CS) approximation at j{sub 0}= 0. The dynamics is resonance-dominated, the probabilities are larger at low K, {sigma}{sub j0} decrease with the collision energy and increase with j{sub 0}, and the CS {sigma}{sub 0} is lower than the CC one. The nonadiabatic interactions play different roles on the quenching dynamics, because the X-tilde{sup 1}A{sup '}-b-tilde{sup 3}A{sup '} SO effects are those most important while the a-tilde{sup 3}A'-b-tilde{sup 3}A{sup '} RT ones are negligible.« less

Letter to the Editors of Physics Today

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, S B; Weiss, M S

2004-11-11

Two points in our recent article on Edward Teller's scientific life (Physics Today, August 2004, page 45) require correction. In our description of Teller's students, we incorrectly stated that Arthur Kantrowitz's thesis was on the generation of hypersonic molecular beams. Actually, his thesis was on heat capacity lags in gas dynamics. Kantrowitz's invention of high intensity sources for molecular beams came later in his career. Maurice Goldhaber has emphasized that the situation with respect to possible nuclear resonances in ({gamma},n) or ({gamma},fission) reactions was quite unclear at the time of George C. Baldwin and G. Stanley Klaiber's papers on thesemore » reactions. This was because the rapid rise of their yield to a prominent peak with increasing energy, followed by a slower fall off was then thought to have been due to the competition between the rapidly rising density of nuclear states and the eventual domination of other reaction channels at higher energies. Goldhaber realized, however, that there could be an analogy between a possible collective nuclear resonance and the restrahl resonance (essentially the transverse optical phonon mode) in polar crystals. Goldhaber sought out Teller because of his paper with Russell Lyddane and Robert Sachs, relating the restrahl frequency to the asymptotic behavior of the crystal's dielectric function. Goldhaber and Teller, in their paper together, went on to predict universal, giant photo-nuclear resonances.« less

Estimated probabilities and volumes of postwildfire debris flows—A prewildfire evaluation for the Pikes Peak area, El Paso and Teller Counties, Colorado

USGS Publications Warehouse

Elliott, John G.; Ruddy, Barbara C.; Verdin, Kristine L.; Schaffrath, Keelin R.

2012-01-01

Debris flows are fast-moving, high-density slurries of water, sediment, and debris that can have enormous destructive power. Although debris flows, triggered by intense rainfall or rapid snowmelt on steep hillsides covered with erodible material, are a common geomorphic process in some unburned areas, a wildfire can transform conditions in a watershed with no recent history of debris flows into conditions that pose a substantial hazard to residents, communities, infrastructure, aquatic habitats, and water supply. The location, extent, and severity of wildfire and the subsequent rainfall intensity and duration cannot be known in advance; however, hypothetical scenarios based on empirical debris-flow models are useful planning tools for conceptualizing potential postwildfire debris flows. A prewildfire study to determine the potential for postwildfire debris flows in the Pikes Peak area in El Paso and Teller Counties, Colorado, was initiated in 2010 by the U.S. Geological Survey, in cooperation with the City of Colorado Springs, Colorado Springs Utilities. The study was conducted to provide a relative measure of which subwatersheds might constitute the most serious potential debris-flow hazards in the event of a large-scale wildfire and subsequent rainfall.

The problem of hole localization in inner-shell states of N2 and CO2 revisited with complete active space self-consistent field approach.

PubMed

Rocha, Alexandre B; de Moura, Carlos E V

2011-12-14

Potential energy curves for inner-shell states of nitrogen and carbon dioxide molecules are calculated by inner-shell complete active space self-consistent field (CASSCF) method, which is a protocol, recently proposed, to obtain specifically converged inner-shell states at multiconfigurational level. This is possible since the collapse of the wave function to a low-lying state is avoided by a sequence of constrained optimization in the orbital mixing step. The problem of localization of K-shell states is revisited by calculating their energies at CASSCF level based on both localized and delocalized orbitals. The localized basis presents the best results at this level of calculation. Transition energies are also calculated by perturbation theory, by taking the above mentioned MCSCF function as zeroth order wave function. Values for transition energy are in fairly good agreement with experimental ones. Bond dissociation energies for N(2) are considerably high, which means that these states are strongly bound. Potential curves along ground state normal modes of CO(2) indicate the occurrence of Renner-Teller effect in inner-shell states. © 2011 American Institute of Physics

Spin-state responses to light impurity substitution in low-spin perovskite LaCoO3

NASA Astrophysics Data System (ADS)

Tomiyasu, Keisuke; Kubota, Yuuki; Shimomura, Saya; Onodera, Mitsugi; Koyama, Syun-Ichi; Nojima, Tsutomu; Ishihara, Sumio; Nakao, Hironori; Murakami, Youichi

2013-06-01

We studied the spin-state responses to light impurity substitution in low-spin perovskite LaCoO3 (Co3+: d6) through magnetization, x-ray fluorescence, and electrical resistivity measurements of single-crystal LaCo0.99M0.01O3 (M = Cr, Mn, Fe, Ni). In the magnetization curves measured at 1.8 K, a change in the spin-state was not observed for Cr, Mn, or Fe substitution but was observed for Ni substitution. Strong magnetic anisotropy was also found in the Ni-substituted sample. The fluorescence measurements revealed that the valences were roughly estimated to be Cr3+, Mn(4-δ)+, Fe(3+δ')+, and Ni3+. From the observed chemical trends, we propose that the chemical potential is a key factor in inducing the change of the low-spin state. By expanding a model of the ferromagnetic spin-state heptamer generated by hole doping [Podlesnyak , Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.101.247603 101, 247603 (2008)], the emergence of highly anisotropic spin-state molecular ferromagnets induced by low-spin Ni3+ with Jahn-Teller activity is suggested. We also discuss applicability of the present results to other materials with Fe (d6).

Walén test and de Hoffmann-Teller frame of interplanetary large-amplitude Alfvén waves

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chao, J. K.; Hsieh, Wen-Chieh; Lee, L. C.

2014-05-10

In this study, three methods of analysis are compared to test the Walén relation. Method 1 requires a good de Hoffmann-Teller (HT) frame. Method 2 uses three components separately to find the frame that is slightly modified from Method 1. This method is intended to improve the accuracy of the HT frame and able to demonstrate the anisotropic property of the fluctuations. The better the relation is, the closer the slope of a regression fitting the data of plasma versus Alfvén velocities is to 1. However, this criterion is based on an average HT frame, and the fitted slope doesmore » not always work for the Walén test because the HT frame can change so fast in the high-speed streams. We propose Method 3 to check the Walén relation using a sequence of data generated by taking the difference of two consecutive values of plasma and Alfvén velocities, respectively. The difference data are independent of the HT frame. We suggest that the ratio of the variances between plasma and Alfvén velocities is a better parameter to qualify the Walén relation. Four cases in two solar wind streams are studied using these three methods. Our results show that when the solar wind HT frame remains stable, all three methods can predict Alfvénic fluctuations well, but Method 3 can better predict the Walén relation when solar wind contains structures with several small streams. A simulated case also demonstrates that Method 3 is better and more robust than Methods 1 and 2. These results are important for a better understanding of Alfvénic fluctuations and turbulence in the solar wind.« less

Pseudo-Jahn-Teller Distortion in Two-Dimensional Phosphorus: Origin of Black and Blue Phases of Phosphorene and Band Gap Modulation by Molecular Charge Transfer.

PubMed

Chowdhury, Chandra; Jahiruddin, Sheik; Datta, Ayan

2016-04-07

Phosphorene (Pn) is stabilized as a layered material like graphite, yet it possess a natural direct band gap (Eg = 2.0 eV). Interestingly, unlike graphene, Pn exhibits a much richer phase diagram which includes distorted forms like the stapler-clip (black Pn, α form) and chairlike (blue Pn, β form) structures. The existence of these phases is attributed to pseudo-Jahn-Teller (PJT) instability of planar hexagonal P6(6-) rings. In both cases, the condition for vibronic instability of the planar P6(6-) rings is satisfied. Doping with electron donors like tetrathiafulvalene and tetraamino-tetrathiafulvalene and electron acceptors like tetracyanoquinodimethane and tetracyanoethylene convert blue Pn into N-type and black Pn into efficient P-type semiconductors, respectively. Interestingly, pristine blue Pn, an indirect gap semiconductor, gets converted into a direct gap semiconductor on electron or hole doping. Because of comparatively smaller undulation in blue Pn (with respect to black Pn), the van der Waals interactions between the dopants and blue Pn is stronger. PJT distortions for two-dimensional phosphorus provides a unified understanding of structural features and chemical reactivity in its different phases.

The vibronic level structure of the cyclopentadienyl radical

NASA Astrophysics Data System (ADS)

Ichino, Takatoshi; Wren, Scott W.; Vogelhuber, Kristen M.; Gianola, Adam J.; Lineberger, W. Carl; Stanton, John F.

2008-08-01

The 351.1 nm photoelectron spectrum of the cyclopentadienide ion has been measured, which reveals the vibronic structure of the X~ 2E1'' state of the cyclopentadienyl radical. Equation-of-motion ionization potential coupled-cluster (EOMIP-CCSD) calculations have been performed to construct a diabatic model potential of the X~ 2E1'' state, which takes into account linear Jahn-Teller effects along the e2' normal coordinates as well as bilinear Jahn-Teller effects along the e2' and ring-breathing a1' coordinates. A simulation based on this ab initio model potential reproduces the spectrum very well, identifying the vibronic levels with linear Jahn-Teller angular momentum quantum numbers of +/-1/2. The angular distributions of the photoelectrons for these vibronic levels are highly anisotropic with the photon energies used in the measurements. A few additional weak photoelectron peaks are observed when photoelectrons ejected parallel to the laser polarization are examined. These peaks correspond to the vibronic levels for out-of-plane modes in the ground X~ 2E1'' state, which arise due to several pseudo-Jahn-Teller interactions with excited states of the radical and quadratic Jahn-Teller interaction in the X~ 2E1'' state. A variant of the first derivative of the energy for the EOMIP-CCSD method has been utilized to evaluate the strength of these nonadiabatic couplings, which have subsequently been employed to construct the model potential of the X~ 2E1'' state with respect to the out-of-plane normal coordinates. Simulations based on the model potential successfully reproduce the weak features that become conspicuous in the 0° spectrum. The present study of the photoelectron spectrum complements a previous dispersed fluorescence spectroscopic study Miller and co-workers [J. Chem. Phys. 114, 4855 (2001); 4869 (2001) Miller and co-workers [J. Chem. Phys.114, 4869 (2001)] to provide a detailed account of the vibronic structure of X~ 2E1'' cyclopentadienyl. The electron

The Synthesis and Characterization of Some Fluoride Perovskites: An Undergraduate Experiment in Solid State Chemistry.

ERIC Educational Resources Information Center

Langley, Richard H.; And Others

1984-01-01

Describes a senior-level experiment dealing with the synthesis and characterization of a perovskite. Since most perovskites are cubic, their characterization by x-ray diffraction is simplified. In addition, magnetic ordering may be observed and the effects of a Jahn-Teller distortion seen. (JN)

Infrared Spectroscopy of the Tropyl Radical in Helium Droplets

DOE PAGES

Kaufmann, Matin; Leicht, Daniel; Havenith, Martina; ...

2016-08-16

Here, the infrared spectrum of themore » $$\\tilde{X}$$ 2E 2" tropyl radical has been recorded in the range of the CH-stretch vibrational modes using the helium droplet isolation technique. Two bands are observed at 3053 and 3058 cm –1. The electronic degeneracy of the ground state results in a Jahn–Teller interaction for two of the CH-stretch modes, i.e., first-order interaction for E 3' symmetry modes and second-order interaction for E 2' symmetry modes. The experimentally observed bands are assigned to the E 1' and E 3' CH-stretch modes. The E 1' mode is infrared-active, whereas the E 3' mode is inactive in the absence of the Jahn–Teller interaction. The transition to the upper component of the Jahn–Teller split E 3' mode gains intensity via vibronic coupling, giving rise to the second experimentally observed band.« less

On the Study of Statistical Intuitions.

DTIC Science & Technology

1981-05-15

teller; 3. Linda is a bank teller who is PAGE 10 active in the feminist movement. In a large sample of statistically naive undergraduates, 86% judged...Linda is both a bank teller and an active feminist must be smaller than the probability that she is a bank teller. (ii) B is more probable than A...because Linda resembles a bank teller who is active in the feminist movement more than she resembles a bank teller. Argument (i) favoring the conjunction

International conference on defects in insulating crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1977-01-01

Short summaries of conference papers are presented. Some of the conference topics included transport properties, defect levels, superionic conductors, radiation effects, John-Teller effect, electron-lattice interactions, and relaxed excited states. (SDF)

The English Revision of The Blegdamsvej Faust

NASA Astrophysics Data System (ADS)

Keck, Karen

2007-03-01

At the 1932 meeting of quantum physicists at Niels Bohr's Copenhagen Institute, participants staged an updated version of Goethe's Faust with Pauli tempting Ehrenfest to accept a chargeless, massless particle, then called the neutron. The most widely read translation of the anonymous Faust: Eine Historie appears in George Gamow's Thirty Years that Shook Physics; his second wife, Barbara, translated the text. Her work masterfully communicates the parallels between Goethe's original and the anonymous parody, but it also rearranges and adds to the parody to strengthen those similarities and to reflect George Gamow's views. The changes emphasize the international and cooperative aspects of physics.

Bcc and Fcc transition metals and alloys: a central role for the Jahn-Teller effect in explaining their ideal and distorted structures.

PubMed

Lee, Stephen; Hoffmann, Roald

2002-05-01

Transition metal elements, alloys, and intermetallic compounds often adopt the body centered cubic (bcc) and face centered cubic (fcc) structures. By comparing quantitative density functional with qualitative tight-binding calculations, we analyze the electronic factors which make the bcc and fcc structures energetically favorable. To do so, we develop a tight-binding function, DeltaE(star), a function that measures the energetic effects of transferring electrons within wave vector stars. This function allows one to connect distortions in solids to the Jahn-Teller effect in molecules and to provide an orbital perspective on structure determining deformations in alloys. We illustrate its use by considering first a two-dimensional square net. We then turn to three-dimensional fcc and bcc structures, and distortions of these. Using DeltaE(star), we rationalize the differences in energy of these structures. We are able to deduce which orbitals are responsible for instabilities in seven to nine valence electron per atom (e(-)/a) bcc systems and five and six e(-)/a fcc structures. Finally we demonstrate that these results account for the bcc and fcc type structures found in both the elements and binary intermetallic compounds of group 4 through 9 transition metal atoms. The outline of a theory of metal structure deformations based on loss of point group operation rather than translational symmetry is presented.

77 FR 24667 - TANF Assistance and Electronic Benefit Transfer Transactions; Request for Public Comment

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-25

... Family Assistance (OFA) is interested in learning about how States deliver Temporary Assistance to Needy... types of restrictions on assistance usage. OFA also is interested in learning about States' current... as ``the use of a credit or debit card service, automated teller machine, point-of-sale terminal, or...

Zero kinetic energy photoelectron spectroscopy of triphenylene.

PubMed

Harthcock, Colin; Zhang, Jie; Kong, Wei

2014-06-28

We report vibrational information of both the first electronically excited state and the ground cationic state of jet-cooled triphenylene via the techniques of resonantly enhanced multiphoton ionization (REMPI) and zero kinetic energy (ZEKE) photoelectron spectroscopy. The first excited electronic state S1 of the neutral molecule is of A1' symmetry and is therefore electric dipole forbidden in the D3h group. Consequently, there are no observable Franck-Condon allowed totally symmetric a1' vibrational bands in the REMPI spectrum. All observed vibrational transitions are due to Herzberg-Teller vibronic coupling to the E' third electronically excited state S3. The assignment of all vibrational bands as e' symmetry is based on comparisons with calculations using the time dependent density functional theory and spectroscopic simulations. When an electron is eliminated, the molecular frame undergoes Jahn-Teller distortion, lowering the point group to C2v and resulting in two nearly degenerate electronic states of A2 and B1 symmetry. Here we follow a crude treatment by assuming that all e' vibrational modes resolve into b2 and a1 modes in the C2v molecular frame. Some observed ZEKE transitions are tentatively assigned, and the adiabatic ionization threshold is determined to be 63 365 ± 7 cm(-1). The observed ZEKE spectra contain a consistent pattern, with a cluster of transitions centered near the same vibrational level of the cation as that of the intermediate state, roughly consistent with the propensity rule. However, complete assignment of the detailed vibrational structure due to Jahn-Teller coupling requires much more extensive calculations, which will be performed in the future.

Orbital disproportionation of electronic density is a universal feature of alkali-doped fullerides

PubMed Central

Iwahara, Naoya; Chibotaru, Liviu F.

2016-01-01

Alkali-doped fullerides show a wide range of electronic phases in function of alkali atoms and the degree of doping. Although the presence of strong electron correlations is well established, recent investigations also give evidence for dynamical Jahn–Teller instability in the insulating and the metallic trivalent fullerides. In this work, to reveal the interplay of these interactions in fullerides with even electrons, we address the electronic phase of tetravalent fulleride with accurate many-body calculations within a realistic electronic model including all basic interactions extracted from first principles. We find that the Jahn–Teller instability is always realized in these materials too. In sharp contrast to the correlated metals, tetravalent system displays uncorrelated band-insulating state despite similar interactions present in both fullerides. Our results show that the Jahn–Teller instability and the accompanying orbital disproportionation of electronic density in the degenerate lowest unoccupied molecular orbital band is a universal feature of fullerides. PMID:27713426

Near-infrared photoabsorption by C60 dianions in a storage ring.

PubMed

Kadhane, U; Andersen, J U; Bonderup, E; Concina, B; Hvelplund, P; Suhr Kirketerp, M-B; Liu, B; Nielsen, S Brøndsted; Panja, S; Rangama, J; Støchkel, K; Tomita, S; Zettergren, H; Hansen, K; Sundén, A E K; Canton, S E; Echt, O; Forster, J S

2009-07-07

We present a detailed study of the electronic structure and the stability of C(60) dianions in the gas phase. Monoanions were extracted from a plasma source and converted to dianions by electron transfer in a Na vapor cell. The dianions were then stored in an electrostatic ring, and their near-infrared absorption spectrum was measured by observation of laser induced electron detachment. From the time dependence of the detachment after photon absorption, we conclude that the reaction has contributions from both direct electron tunneling to the continuum and vibrationally assisted tunneling after internal conversion. This implies that the height of the Coulomb barrier confining the attached electrons is at least approximately 1.5 eV. For C(60)(2-) ions in solution electron spin resonance measurements have indicated a singlet ground state, and from the similarity of the absorption spectra we conclude that also the ground state of isolated C(60)(2-) ions is singlet. The observed spectrum corresponds to an electronic transition from a t(1u) lowest unoccupied molecular orbital (LUMO) of C(60) to the t(1g) LUMO+1 level. The electronic levels of the dianion are split due to Jahn-Teller coupling to quadrupole deformations of the molecule, and a main absorption band at 10,723 cm(-1) corresponds to a transition between the Jahn-Teller ground states. Also transitions from pseudorotational states with 200 cm(-1) and (probably) 420 cm(-1) excitation are observed. We argue that a very broad absorption band from about 11,500 cm(-1) to 13,500 cm(-1) consists of transitions to so-called cone states, which are Jahn-Teller states on a higher potential-energy surface, stabilized by a pseudorotational angular momentum barrier. A previously observed, high-lying absorption band for C(60)(-) may also be a transition to a cone state.

Present state of HDTV coding in Japan and future prospect

NASA Astrophysics Data System (ADS)

Murakami, Hitomi

The development status of HDTV digital codecs in Japan is evaluated; several bit rate-reduction codecs have been developed for 1125 lines/60-field HDTV, and performance trials have been conducted through satellite and optical fiber links. Prospective development efforts will attempt to achieve more efficient coding schemes able to reduce the bit rate to as little as 45 Mbps, as well as to apply coding schemes to automated teller machine networks.

Theoretical investigation of two-particle two-hole effects on spin-isospin excitations through charge-exchange reactions

NASA Astrophysics Data System (ADS)

Fukui, Tokuro; Minato, Futoshi

2017-11-01

Background: Coherent one-particle one-hole (1p1h) excitations have given us effective insights into general nuclear excitations. However, the two-particle two-hole (2p2h) excitation beyond 1p1h is now recognized as critical for the proper description of experimental data of various nuclear responses. Purpose: The spin-flip charge-exchange reactions 48Ca(p ,n )48Sc are investigated to clarify the role of the 2p2h effect on their cross sections. The Fermi transition of 48Ca via the (p ,n ) reaction is also investigated in order to demonstrate our framework. Methods: The transition density is calculated microscopically with the second Tamm-Dancoff approximation, and the distorted-wave Born approximation is employed to describe the reaction process. A phenomenological one-range Gaussian interaction is used to prepare the form factor. Results: For the Fermi transition, our approach describes the experimental behavior of the cross section better than the Lane model, which is the conventional method. For spin-flip excitations including the GT transition, the 2p2h effect decreases the magnitude of the cross section and does not change the shape of the angular distribution. The Δ l =2 transition of the present reaction is found to play a negligible role. Conclusions: The 2p2h effect will not change the angular-distributed cross section of spin-flip responses. This is because the transition density of the Gamow-Teller response, the leading contribution to the cross section, is not significantly varied by the 2p2h effect.

Beta delayed neutrons for nuclear structure and astrophysics

NASA Astrophysics Data System (ADS)

Grzywacz, Robert

2014-09-01

Beta-delayed neutron emission (β xn) is a significant or even dominant decay channel for the majority of very neutron-rich nuclei, especially for those on the r-process path. The recent theoretical models predicts that it may play more significant role then previously expected for astrophysics and this realization instigated a renewed experimental interest in this topic as a part of a larger scope of research on beta-decay strength distribution. Because studies of the decay strength directly probe relevant physics on the microscopic level, energy-resolved measurements of the beta-decay strength distribution is a better test of nuclear models than traditionally used experimental observables like half-lives and neutron branching ratios. A new detector system called the Versatile Array of Neutron Detectors at Low Energy (VANDLE) was constructed to directly address this issue. In its first experimental campaign at the Holifield Radioactive Ion Beam Facility neutron energy spectra in key regions of the nuclear chart were measured: near the shell closures at 78Ni and 132Sn, and for the deformed nuclei near 100Rb. In several cases, unexpectedly intense and concentrated, resonant-like, high-energy neutron structures were observed. These results were interpreted within shell model framework which clearly indicated that these neutron emission is driven by nuclear structure effects and are due to large Gamow-Teller type transition matrix elements. This research was sponsored in part by the National Nuclear Security Administration under the Stewardship Science Academic Alliances program through DOE Cooperative Agreement No. DE-FG52-08NA28552.

Precision half-life measurement of 11C: The most precise mirror transition F t value

NASA Astrophysics Data System (ADS)

Valverde, A. A.; Brodeur, M.; Ahn, T.; Allen, J.; Bardayan, D. W.; Becchetti, F. D.; Blankstein, D.; Brown, G.; Burdette, D. P.; Frentz, B.; Gilardy, G.; Hall, M. R.; King, S.; Kolata, J. J.; Long, J.; Macon, K. T.; Nelson, A.; O'Malley, P. D.; Skulski, M.; Strauss, S. Y.; Vande Kolk, B.

2018-03-01

Background: The precise determination of the F t value in T =1 /2 mixed mirror decays is an important avenue for testing the standard model of the electroweak interaction through the determination of Vu d in nuclear β decays. 11C is an interesting case, as its low mass and small QE C value make it particularly sensitive to violations of the conserved vector current hypothesis. The present dominant source of uncertainty in the 11CF t value is the half-life. Purpose: A high-precision measurement of the 11C half-life was performed, and a new world average half-life was calculated. Method: 11C was created by transfer reactions and separated using the TwinSol facility at the Nuclear Science Laboratory at the University of Notre Dame. It was then implanted into a tantalum foil, and β counting was used to determine the half-life. Results: The new half-life, t1 /2=1220.27 (26 ) s, is consistent with the previous values but significantly more precise. A new world average was calculated, t1/2 world=1220.41 (32 ) s, and a new estimate for the Gamow-Teller to Fermi mixing ratio ρ is presented along with standard model correlation parameters. Conclusions: The new 11C world average half-life allows the calculation of a F tmirror value that is now the most precise value for all superallowed mixed mirror transitions. This gives a strong impetus for an experimental determination of ρ , to allow for the determination of Vu d from this decay.

Solvent effects on the vibronic one-photon absorption profiles of dioxaborine heterocycles

NASA Astrophysics Data System (ADS)

Wang, Yan-Hua; Halik, Marcus; Wang, Chuan-Kui; Marder, Seth R.; Luo, Yi

2005-11-01

The vibronic profiles of one-photon absorption spectra of dioxaborine heterocycles in gas phase and solution have been calculated at the Hartree-Fock and density-functional-theory levels. The polarizable continuum model has been applied to simulate the solvent effect, while the linear coupling model is used to compute the Franck-Condon and Herzberg-Teller contributions. It is found that a good agreement between theory and experiment can be achieved when the solvent effect and electron correlation are taken into account simultaneously. For the first excited charge-transfer state, the maximum of its Herzberg-Teller profile is blueshifted from that of the Franck-Condon profile. The shifted energy is found to be around 0.2eV, which agrees well with the measured energy difference between two- and one-photon absorptions of the first excited state.

Electron momentum spectroscopy of dimethyl ether taking account of nuclear dynamics in the electronic ground state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morini, Filippo; Deleuze, Michael Simon, E-mail: michael.deleuze@uhasselt.be; Watanabe, Noboru

The influence of nuclear dynamics in the electronic ground state on the (e,2e) momentum profiles of dimethyl ether has been analyzed using the harmonic analytical quantum mechanical and Born-Oppenheimer molecular dynamics approaches. In spite of fundamental methodological differences, results obtained with both approaches consistently demonstrate that molecular vibrations in the electronic ground state have a most appreciable influence on the momentum profiles associated to the 2b{sub 1}, 6a{sub 1}, 4b{sub 2}, and 1a{sub 2} orbitals. Taking this influence into account considerably improves the agreement between theoretical and newly obtained experimental momentum profiles, with improved statistical accuracy. Both approaches point outmore » in particular the most appreciable role which is played by a few specific molecular vibrations of A{sub 1}, B{sub 1}, and B{sub 2} symmetries, which correspond to C–H stretching and H–C–H bending modes. In line with the Herzberg-Teller principle, the influence of these molecular vibrations on the computed momentum profiles can be unraveled from considerations on the symmetry characteristics of orbitals and their energy spacing.« less

Post-Attack Economic Stabilization Issues for Federal, State, and Local Governments

DTIC Science & Technology

1985-02-01

workers being transfered from large urban areas to production facilities in areas of lower risk . In another case, rent control staff should be quickly...food supermarkets , which do not universally accept bank cards. 3 0 A requirement will still exist for a large number of credit cards. While there is some...separate system is required for rationing. For example, the increasingly popular automatic teller machine ( ATM ) debit card routinely accesses both a

Crystal structure, oxidation state and magnetism of Sr{sub x}La{sub 2−x}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} (x=1, 1.5)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lü, Minfeng, E-mail: m.f.lv@ciac.jl.cn; Deng, Xiaolong; Waerenborgh, João C.

2014-03-15

Sr{sub x}La{sub 2−x}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} (x=1, 1.5) oxides with K{sub 2}NiF{sub 4}-type structure were prepared by solid state reaction and characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, magnetic and electrical resistivity measurements. The SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} phase was obtained for the first time with a negligible amount of impurities. The octahedral Cu/RuO{sub 6} units are more elongated in SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} than in Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} indicating a greater extent of static Jahn–Teller distortion. XPS suggests that mixed ion pairs Ru{sup 5+}/Ru{sup 4+}↔Cu{sup +}/Cu{sup 2+} are present in SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4}, whilemore » Ru remains as Ru{sup 5+} and Cu as Cu{sup 2+} in Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4}. Both samples show spin-glass behavior, which can be explained by competition between ferromagnetic and antiferromagnetic superexchange interactions. The negative Weiss temperature estimated for SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4}, −318 K, is significantly lower than −11.5 K deduced for Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} which may be related to the higher static Jahn–Teller distortion in the former oxide. -- Graphical abstract: SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} with K{sub 2}NiF{sub 4}-type structure show a larger static Jahn–Teller distortion than Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4}, which may be related to stronger antiferromagnetic superexchange interactions. Highlights: • SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} (I) larger Jahn–Teller (J–T) distortion than Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} (II). • Octahedral Cu/RuO{sub 6} units are more elongated in I than in II. • Mixed ion pairs Ru{sup 5+}/Ru{sup 4+}↔Cu{sup +}/Cu{sup 2+} are present in I, while Ru remains as Ru{sup 5+} and Cu as Cu{sup 2+} in II. • Negative Weiss temperature of I significantly lower

Magnetostructural Properties of Colossal Magnetoresistance Manganites Under External Magnetic Fields and Uniaxial Pressure

NASA Astrophysics Data System (ADS)

Kaplan, Michael; Zimmerman, George

2002-03-01

In the colossal magnetoresistance manganites the transport and magnetostructural properties are tightly connected [1,2]. Many magnetic field induced structural phase transitions and anomalous magnetoacoustical properties continue to be discovered in various manganite derivatives. Nevertheless the mechanism of structural transitions and microscopic theory of corresponding anomalous properties are still to be completely understood. Here we present a microscopic model of magnetic field and uniaxial pressure induced structural phase transitions in lightly doped manganites. The model is based on the cooperative Jahn-Teller effect which takes into account the Mn3+-ground doublet and excited triplet electronic states. Numerous calculations for different orientation magnetic field suggest the explanations of the origin of the structural transitions and of the measured magnetostriction data. The calculations for the two-sublattice antiferrodistortive crystals under uniaxial pressure support the idea of metaelasticity - a property typical for Jahn-Teller antiferroelastics. 1.Y. Tokura, ed. Colossal Magnetoresistance Oxides. Gordon & Breach, London, 2000. 2.M. Kaplan, G. Zimmerman, eds. Vibronic Interactions: Jahn-Teller Effect in Crystal and Molecules. NATO Science Series, Dordrecht/Boston/London, 2001

Theoretical Studies of Relaxation and Optical Properties of Polymers

NASA Astrophysics Data System (ADS)

Jin, Bih-Yaw

1993-01-01

This thesis is composed of two parts. In the part one, the empirical correlation between the logarithm of tunneling splittings and the temperature at which the spin-lattice relaxation time is minimum for methyl groups in different molecular crystals is explained successfully by taking multiphonon processes into account. We show that one phonon transitions dominate in the low barrier limit. However, in the intermediate barrier range and high barrier limit, it is necessary to include multiphonon processes. We also show that the empirical correlation depends only logarithmically on the details of the phonon bath. In the part two, we have investigated the optical and relaxation properties of conjugated polymers. The connection between the vibronic picture of Raman scattering and the third order perturbation approach in solid state physics is clarified in chapter 2. Starting from the Kramers -Heissenberg-Dirac formula for Raman scattering, we derive expressions for the Condon and Herzberg-Teller terms from a simple two-level system to a two-band system, i.e. polyacetylene, by using traditional vibronic picture. Both the Condon and Herzberg-Teller terms contribute to two-band processes, while three-band processes consist only of Herzberg-Teller terms in the solid state limit. Close to resonance the Condon term dominates and converges to the usual solid state result. In the off-resonance region the Herzberg -Teller term is comparable to Condon term for both small molecule and solid state system. In chapter 3, we will concentrate on the lattice relaxation of the lowest optically allowed 1B_ {u} state, especially, the effect of electron correlation on the excited state geometric relaxation for finite polyenes. We have examined the competition between electron-electron interaction and electron-phonon coupling on the formation of localized lattice distortion in the 1B_{u} state for finite polyene with chain length up to 30 double bonds. The chain length dependence of the

Constraint of the 13C(α,n) Cross Section Toward Astrophysical Energies for the Main s-Process

NASA Astrophysics Data System (ADS)

Toomey, Rebecca; Febbraro, Michael T.; Pain, Steven D.; Peters, William A.; Cizewski, Jolie A.; Havener, Charles C.; Bannister, Mark E.; Chipps, Kelly A.; Walter, David G.; Ummel, Chad C.; Sims, Harrison

2017-09-01

The slow neutron capture process (s-process) typically occurs in relatively low neutron flux environments, such as AGB stars, and is a key mechanism in heavy-element synthesis. The dominant source of neutrons for the main s-process is the 13C(α,n) reaction, which proceeds at stellar temperatures ( 0.1 GK, 200 keV), via reactions well below the Coulomb barrier. Direct measurements of the reaction rate in the Gamow window ( 140- 230 keV) is difficult, complicated by the low yields and high beam currents required. Current measurements have constrained the cross section down to approximately 320 keV - still well above stellar conditions- with significant statistical uncertainties. These uncertainties, and the influence of a near-threshold 1 /2+ state at 6.4 MeV, means that extrapolation of the data into the Gamow window is unreliable. These measurements typically use high-efficiency moderated neutron counter detectors, meaning energy information of the incident neutrons is lost. A quasi-spectroscopic approach has been used to measure the 13C(α,n) reaction rate at energies between 300-350 keV with the aim of reducing uncertainties in current measurements. Work supported in part by U.S. D.O.E., the National Science Foundation and the LDRD Program of ORNL, managed by UT-Battelle, LLC.

Negative Ion Photoelectron Spectroscopy Confirms the Prediction that D-3h Carbontrioxide (CO 3) Has a Singlet Ground State

DOE PAGES

Hrovat, David; Hou, Gao-Lei; Chen, Bo; ...

2015-11-13

The CO 3 radical anion (CO 3 •–) has been formed by electrospraying carbonate dianion (CO 3 2–) into the gas phase. The negative ion photoelectron (NIPE) spectrum of CO 3 •– shows that, unlike trimethylenemethane [C(CH 2) 3], carbontrioxide (CO 3) has a singlet ground state. From the NIPE spectrum, the electron affinity of CO 3 was determined to be EA = 4.06 ± 0.03 eV, and the singlet-triplet energy difference was found to be ΔEST = - 17.8 ± 0.9 kcal/mol. B3LYP, CCSD(T), and CASPT2 calculations all find that the two lowest triplet states of CO 3 aremore » very close in energy, a prediction that is confirmed by the relative intensities of the bands in the NIPE spectrum of CO 3 •–. The 560 cm -1 vibrational progression, seen in the low energy region of the triplet band, enables the identification of the lowest, Jahn-Teller-distorted, triplet state as 3A 1, in which both unpaired electrons reside in σ MOs, rather than 3A 2, in which one unpaired electron occupies the b 2 σ MO, and the other occupies the b 1 π MO.« less

Comment on 'Ground state of octahedral platinum hexafluoride'

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gabuda, S. P.; Kozlova, S. G.

2009-05-15

It is shown that the principal results of a recent work by Alvarez-Thon et al. [Phys. Rev. A 77, 034502 (2008)] are in conflict with earlier work of the present authors [JETP Lett. 73, 35 (2001)] and also with a well known result concerning magnetic properties, NMR, and Jahn-Teller effect in the systems possessing even number of d electrons. This can be attributed to the fact that Alvarez-Thon et al. did not account for the influence of {sup 19}F and {sup 195}Pt nuclear magnetic moments and vibronic interactions on the wave function of PtF{sub 6} molecules.

Signatures of non-adiabatic dynamics in the fine-structure state distributions of the OH(X̃/Ã) products in the B-band photodissociation of H2O.

PubMed

Zhou, Linsen; Xie, Daiqian; Guo, Hua

2015-03-28

A detailed quantum mechanical characterization of the photodissociation dynamics of H2O at 121.6 nm is presented. The calculations were performed using a full-dimensional wave packet method on coupled potential energy surfaces of all relevant electronic states. Our state-to-state model permits a detailed analysis of the OH(X̃/Ã) product fine-structure populations as a probe of the non-adiabatic dissociation dynamics. The calculated rotational state distributions of the two Λ-doublet levels of OH(X̃, v = 0) exhibit very different characteristics. The A' states, produced mostly via the B̃→X̃ conical intersection pathway, have significantly higher populations than the A″ counterparts, which are primarily from the B̃→Ã Renner-Teller pathway. The former features a highly inverted and oscillatory rotational state distribution, while the latter has a smooth distribution with much less rotational excitation. In good agreement with experiment, the calculated total OH(X̃) rotational state distribution and anisotropy parameters show clear even-odd oscillations, which can be attributed to a quantum mechanical interference between waves emanating from the HOH and HHO conical intersections in the B̃→X̃ non-adiabatic pathway. On the other hand, the experiment-theory agreement for the OH(Ã) fragment is also satisfactory, although some small quantitative differences suggest remaining imperfections of the ab initio based potential energy surfaces.

Eigenfunction Expansions and Lippmann-Schwinger Formulas

NASA Astrophysics Data System (ADS)

Gadella, M.; Kielanowski, P.

2011-12-01

In this paper we discuss in the mathematically precise way the definition of a resonance, that requires two Hamiltonians (free and perturbed), the notion of Gamow vectors, Lippmann-Schwinger equations and the analytic properties of their solutions in the context of the Gamow vectors. Next we discuss the eigenfunction expansions in the presence of resonances. In the case of the Friedrichs model, the precise form of these generalized eigenfunctions has been given in the literature. Although there are two families of eigenfunction expansions which are related through the time reversal operator, free and perturbed Hamiltonians are time invariant. On the other hand, PT symmetries play no role in this discussion. Our discussion clarifies the results of the paper [1], which contains imprecise or even wrong statements.

Femtosecond dynamics of correlated many-body states in C60 fullerenes

NASA Astrophysics Data System (ADS)

Usenko, Sergey; Schüler, Michael; Azima, Armin; Jakob, Markus; Lazzarino, Leslie L.; Pavlyukh, Yaroslav; Przystawik, Andreas; Drescher, Markus; Laarmann, Tim; Berakdar, Jamal

2016-11-01

Fullerene complexes may play a key role in the design of future molecular electronics and nanostructured devices with potential applications in light harvesting using organic solar cells. Charge and energy flow in these systems is mediated by many-body effects. We studied the structure and dynamics of laser-induced multi-electron excitations in isolated C60 by two-photon photoionization as a function of excitation wavelength using a tunable fs UV laser and developed a corresponding theoretical framework on the basis of ab initio calculations. The measured resonance line width gives direct information on the excited state lifetime. From the spectral deconvolution we derive a lower limit for purely electronic relaxation on the order of {τ }{el}={10}-3+5 fs. Energy dissipation towards nuclear degrees of freedom is studied with time-resolved techniques. The evaluation of the nonlinear autocorrelation trace gives a characteristic time constant of {τ }{vib}=400+/- 100 fs for the exponential decay. In line with the experiment, the observed transient dynamics is explained theoretically by nonadiabatic (vibronic) couplings involving the correlated electronic, the nuclear degrees of freedom (accounting for the Herzberg-Teller coupling), and their interplay.

Measurement of the β-asymmetry parameter of Cu67 in search for tensor-type currents in the weak interaction

NASA Astrophysics Data System (ADS)

Soti, G.; Wauters, F.; Breitenfeldt, M.; Finlay, P.; Herzog, P.; Knecht, A.; Köster, U.; Kraev, I. S.; Porobic, T.; Prashanth, P. N.; Towner, I. S.; Tramm, C.; Zákoucký, D.; Severijns, N.

2014-09-01

Background: Precision measurements at low energy search for physics beyond the standard model in a way complementary to searches for new particles at colliders. In the weak sector the most general β-decay Hamiltonian contains, besides vector and axial-vector terms, also scalar, tensor, and pseudoscalar terms. Current limits on the scalar and tensor coupling constants from neutron and nuclear β decay are on the level of several percent. Purpose: Extracting new information on tensor coupling constants by measuring the β-asymmetry parameter in the pure Gamow-Teller decay of Cu67, thereby testing the V-A structure of the weak interaction. Method: An iron sample foil into which the radioactive nuclei were implanted was cooled down to mK temperatures in a 3He-4He dilution refrigerator. An external magnetic field of 0.1 T, in combination with the internal hyperfine magnetic field, oriented the nuclei. The anisotropic β radiation was observed with planar high-purity germanium detectors operating at a temperature of about 10 K. An on-line measurement of the β asymmetry of Cu68 was performed as well for normalization purposes. Systematic effects were investigated using geant4 simulations. Results: The experimental value, Ã=0.587(14), is in agreement with the standard model value of 0.5991(2) and is interpreted in terms of physics beyond the standard model. The limits obtained on possible tensor-type charged currents in the weak interaction Hamiltonian are -0.045<(CT+CT')/CA<0.159 (90% C.L.). Conclusions: The obtained limits are comparable to limits from other correlation measurements in nuclear β decay and contribute to further constraining tensor coupling constants.

Getting the Bigger Picture With Digital Surveillance

NASA Technical Reports Server (NTRS)

2002-01-01

Through a Space Act Agreement, Diebold, Inc., acquired the exclusive rights to Glenn Research Center's patented video observation technology, originally designed to accelerate video image analysis for various ongoing and future space applications. Diebold implemented the technology into its AccuTrack digital, color video recorder, a state-of- the-art surveillance product that uses motion detection for around-the- clock monitoring. AccuTrack captures digitally signed images and transaction data in real-time. This process replaces the onerous tasks involved in operating a VCR-based surveillance system, and subsequently eliminates the need for central viewing and tape archiving locations altogether. AccuTrack can monitor an entire bank facility, including four automated teller machines, multiple teller lines, and new account areas, all from one central location.

78 FR 39331 - Sigrid Sanchez, M.D.; Decision and Order

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-01

... ``as the `Pharmacy.''' Id. The Pharmacy had a ``teller like window where the prescription drug products... inventory.'' Id. She then stated that ``no prior inventories or logs were made available to'' her. Id... dispensing log. The Government also alleges that ``Respondent failed to store [the] controlled substances in...

Proton-decay spectroscopic studies of the exotic nuclides aluminum-23, silicon-23, aluminum-22 and rubidium-77

NASA Astrophysics Data System (ADS)

Rowe, Michael William

Aluminum-23 was produced by 40 MeV 3He2+ bombardments of Mg targets in four experiments at the LBNL 88' ' Cyclotron. Reaction products were transported via helium-jet to a detection chamber where they were counted using two low-energy particle-identification (PI) telescopes. New proton groups were observed with laboratory energies (and intensities relative to the known peak at 838 +/- 5 keV) of 246 20 (33 +/- 3%) and 556 +/- 5 keV (68 +/- 5%), respectively. Several possible decay assignments are discussed for the former group. The possibility that it originates from the decay through the isobaric analog state (IAS) and corresponding implications for isospin mixing and the proton-capture resonance strength are discussed. The Gamow-Teller strength function has been deduced from these and several weaker proton transitions; the results are compared with theoretical predictions. Silicon-23 and 22Al were produced in a 110 MeV 3He2+ bombardment of a 24Mg target; reaction products were transported via helium jet and observed by two PI telescopes with proton sensitivity from 0-35-12.5 MeV. Three weak proton peaks at 7673 +/- 33, 9642 +/- 57 and 10861 +/- 68 keV have been tentatively assigned to the beta-delayed proton decay of 23Si through its IAS. From these results, the estimated 23Si mass excess is 23.25 +/- 0.05 MeV. Beta-delayed two-proton sum peaks were observed at 4478 +/- 15 and 6111 +/- 15 keV (c.m.), in agreement with earlier work an the decay of 22Al at wide relative-emission angles. The energies of several weaker two-proton sum peaks were compared with predicted and experimental values for the β-2p decay of 23Si. A search for proton emission from a predicted 19/2- isomer of 77Rb has been performed in three bombardments of Ca targets by 40Ca beams at energies of 145,160 and 132 MeV. Products of the first two bombardments were transported via helium jet and observed by two PI telescopes. In the third bombardment, the mass separator RAMA transported mass-77

Proton-decay spectroscopic studies of the exotic nuclides aluminum-23, silicon-23, aluminum-22 and rubidium-77

NASA Astrophysics Data System (ADS)

Rowe, Michael William

1998-09-01

Aluminum-23 was produced by 40 MeV 3He2+ bombardments of Mg targets in four experiments at the LBNL 88' ' Cyclotron. Reaction products were transported via helium-jet to a detection chamber where they were counted using two low-energy particle-identification (PI) telescopes. New proton groups were observed with laboratory energies (and intensities relative to the known peak at 838 +/- 5 keV) of 246 20 (33 +/- 3%) and 556 +/- 5 keV (68 +/- 5%), respectively. Several possible decay assignments are discussed for the former group. The possibility that it originates from the decay through the isobaric analog state (IAS) and corresponding implications for isospin mixing and the proton-capture resonance strength are discussed. The Gamow-Teller strength function has been deduced from these and several weaker proton transitions; the results are compared with theoretical predictions. Silicon-23 and 22Al were produced in a 110 MeV 3He2+ bombardment of a 24Mg target; reaction products were transported via helium jet and observed by two PI telescopes with proton sensitivity from 0-35-12.5 MeV. Three weak proton peaks at 7673 +/- 33, 9642 +/- 57 and 10861 +/- 68 keV have been tentatively assigned to the beta-delayed proton decay of 23Si through its IAS. From these results, the estimated 23Si mass excess is 23.25 +/- 0.05 MeV. Beta-delayed two-proton sum peaks were observed at 4478 +/- 15 and 6111 +/- 15 keV (c.m.), in agreement with earlier work an the decay of 22Al at wide relative-emission angles. The energies of several weaker two-proton sum peaks were compared with predicted and experimental values for the β-2p decay of 23Si. A search for proton emission from a predicted 19/2- isomer of 77Rb has been performed in three bombardments of Ca targets by 40Ca beams at energies of 145,160 and 132 MeV. Products of the first two bombardments were transported via helium jet and observed by two PI telescopes. In the third bombardment, the mass separator RAMA transported mass-77

Multi-State Vibronic Interactions in Fluorinated Benzene Radical Cations.

NASA Astrophysics Data System (ADS)

Faraji, S.; Köppel, H.

2009-06-01

Conical intersections of potential energy surfaces have emerged as paradigms for signalling strong nonadiabatic coupling effects. An important class of systems where some of these effects have been analyzed in the literature, are the benzene and benzenoid cations, where the electronic structure, spectroscopy, and dynamics have received great attention in the literature. In the present work a brief overview is given over our theoretical treatments of multi-mode and multi-state vibronic interactions in the benzene radical cation and some of its fluorinated derivatives. The fluorobenzene derivatives are of systematic interest for at least two different reasons. (1) The reduction of symmetry by incomplete fluorination leads to a disappearance of the Jahn-Teller effect present in the parent cation. (2) A specific, more chemical effect of fluorination consists in the energetic increase of the lowest σ-type electronic states of the radical cations. The multi-mode multi-state vibronic interactions between the five lowest electronic states of the fluorobenzene radical cations are investigated theoretically, based on ab initio electronic structure data, and employing the well-established linear vibronic coupling model, augmented by quadratic coupling terms for the totally symmetric vibrational modes. Low-energy conical intersections, and strong vibronic couplings are found to prevail within the set of tilde{X}-tilde{A} and tilde{B}-tilde{C}-tilde{D} cationic states, while the interactions between these two sets of states are found to be weaker and depend on the particular isomer. This is attributed to the different location of the minima of the various conical intersections occurring in these systems. Wave-packet dynamical simulations for these coupled potential energy surfaces, utilizing the powerful multi-configuration time-dependent Hartree method are performed. Ultrafast internal conversion processes and the analysis of the MATI and photo-electron spectra shed new light

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, S B

Much has been written about Edward TEller, but little of it is objective. Given, on the one hand, his position as one of the most inventive theoretical physicists of the 20th century, and on the other, his central role in the development and advocacy of thermonuclear weapons, one might imagine it impossible at this point in history to write a scholarly, impartial account of Teller's life and his impact. Now, however, Istvan Hargittai, a prominent Hungarian physical chemist and historian of science, has written a balanced, thoughtful, and beautifully research biography that comes closest. Hargittai is uniquely qualified for thismore » difficult task. Coming a generation and a half later from a similar Hungarian-Jewish background, Hargittai understands well the influences and terrible events that shaped Teller. The advent of virulent, political anti-Semitism, first in Hungary and then in Germany, made Teller twice a refugee. Both Teller and Hargittai lost close family in the Holocaust; Hargittai was himself liberated from a Nazi concentration camp as a child. While Teller was in the US by then, his and Hargittai's surviving family members in Hungary suffered mistreatment at the hands of the postwar Hungarian Communist dictatorship. Hargittai's informed Eastern European perspective also provides a fresh viewpoint to the cold war context of the second half of Teller's career. Furthermore, Hargittai's own scientific work in molecular structure clearly makes him appreciate of Teller's breakthroughs in that field in the 1930s.« less

Usability of a virtual reality environment simulating an automated teller machine for assessing and training persons with acquired brain injury.

PubMed

Fong, Kenneth N K; Chow, Kathy Y Y; Chan, Bianca C H; Lam, Kino C K; Lee, Jeff C K; Li, Teresa H Y; Yan, Elaine W H; Wong, Asta T Y

2010-04-30

This study aimed to examine the usability of a newly designed virtual reality (VR) environment simulating the operation of an automated teller machine (ATM) for assessment and training. Part I involved evaluation of the sensitivity and specificity of a non-immersive VR program simulating an ATM (VR-ATM). Part II consisted of a clinical trial providing baseline and post-intervention outcome assessments. A rehabilitation hospital and university-based teaching facilities were used as the setting. A total of 24 persons in the community with acquired brain injury (ABI)--14 in Part I and 10 in Part II--made up the participants in the study. In Part I, participants were randomized to receive instruction in either an "early" or a "late" VR-ATM program and were assessed using both the VR program and a real ATM. In Part II, participants were assigned in matched pairs to either VR training or computer-assisted instruction (CAI) teaching programs for six 1-hour sessions over a three-week period. Two behavioral checklists based on activity analysis of cash withdrawals and money transfers using a real ATM were used to measure average reaction time, percentage of incorrect responses, level of cues required, and time spent as generated by the VR system; also used was the Neurobehavioral Cognitive Status Examination. The sensitivity of the VR-ATM was 100% for cash withdrawals and 83.3% for money transfers, and the specificity was 83% and 75%, respectively. For cash withdrawals, the average reaction time of the VR group was significantly shorter than that of the CAI group (p = 0.021). We found no significant differences in average reaction time or accuracy between groups for money transfers, although we did note positive improvement for the VR-ATM group. We found the VR-ATM to be usable as a valid assessment and training tool for relearning the use of ATMs prior to real-life practice in persons with ABI.

Usability of a virtual reality environment simulating an automated teller machine for assessing and training persons with acquired brain injury

PubMed Central

2010-01-01

Objective This study aimed to examine the usability of a newly designed virtual reality (VR) environment simulating the operation of an automated teller machine (ATM) for assessment and training. Design Part I involved evaluation of the sensitivity and specificity of a non-immersive VR program simulating an ATM (VR-ATM). Part II consisted of a clinical trial providing baseline and post-intervention outcome assessments. Setting A rehabilitation hospital and university-based teaching facilities were used as the setting. Participants A total of 24 persons in the community with acquired brain injury (ABI) - 14 in Part I and 10 in Part II - made up the participants in the study. Interventions In Part I, participants were randomized to receive instruction in either an "early" or a "late" VR-ATM program and were assessed using both the VR program and a real ATM. In Part II, participants were assigned in matched pairs to either VR training or computer-assisted instruction (CAI) teaching programs for six 1-hour sessions over a three-week period. Outcome Measures Two behavioral checklists based on activity analysis of cash withdrawals and money transfers using a real ATM were used to measure average reaction time, percentage of incorrect responses, level of cues required, and time spent as generated by the VR system; also used was the Neurobehavioral Cognitive Status Examination. Results The sensitivity of the VR-ATM was 100% for cash withdrawals and 83.3% for money transfers, and the specificity was 83% and 75%, respectively. For cash withdrawals, the average reaction time of the VR group was significantly shorter than that of the CAI group (p = 0.021). We found no significant differences in average reaction time or accuracy between groups for money transfers, although we did note positive improvement for the VR-ATM group. Conclusion We found the VR-ATM to be usable as a valid assessment and training tool for relearning the use of ATMs prior to real-life practice in persons

Storytelling as an age-dependent skill: oral recall of orally presented stories.

PubMed

Mergler, N L; Faust, M; Goldstein, M D

During experiment 1, three taped prose passages read by college student, middle-aged, or old tellers were orally recalled by college students in an incidental memory paradigm. More story units were remembered as the age of the teller increased (r = +.642, p less than .05). Comparison of these results, with prior research using written, as opposed to oral, presentation and recall of these stories, showed no differences in specific story units remembered. Teller age predicted recall on the two "storied" passages. These passages elicited more favorable comments from listeners when read by older tellers. The third, descriptive passage was less favorably regarded by listeners hearing older tellers. During experiment 2, taped storied passages read by middle-aged tellers were falsely attributed to young, middle-aged, or old persons before the college students listened. Incidental recall did not show an age of teller effect in this case, but the listener's evaluation of the speaker exhibited age-dependent stereotypes. It was concluded that 1) physical qualities of older voices lead to more effective oral transmission; 2) that one expects to receive certain types of oral information from older persons; and 3) that a mismatch between physical vocal quality and age attribution effects evaluation of the speaker, not recall of the information.

Turning a Private Label Bank Card into a Multi-function Campus ID Card.

ERIC Educational Resources Information Center

James, Thomas G.; Norwood, Bill R.

1991-01-01

This article describes the development at Florida State University of the Seminole ACCESS card, which functions simultaneously as a bank automated teller machine card, a student identification card, and a debit card. Explained are the partnership between the university and the bank charge card center, funding system, technologies involved, and…

Spin dynamics and orbital state in LaTiO3

PubMed

Keimer; Casa; Ivanov; Lynn; Zimmermann; Hill; Gibbs; Taguchi; Tokura

2000-10-30

A neutron scattering study of the Mott-Hubbard insulator LaTiO3 ( T(N) = 132 K) reveals a spin wave spectrum that is well described by a nearest-neighbor superexchange constant J = 15.5 meV and a small Dzyaloshinskii-Moriya interaction ( D = 1.1 meV). The nearly isotropic spin wave spectrum is surprising in view of the absence of a static Jahn-Teller distortion that could quench the orbital angular momentum, and it may indicate strong orbital fluctuations. A resonant x-ray scattering study has uncovered no evidence of orbital order in LaTiO3.

Molecular geometry of vanadium dichloride and vanadium trichloride: a gas-phase electron diffraction and computational study.

PubMed

Varga, Zoltán; Vest, Brian; Schwerdtfeger, Peter; Hargittai, Magdolna

2010-03-15

The molecular geometries of VCl2 and VCl3 have been determined by computations and gas-phase electron diffraction (ED). The ED study is a reinvestigation of the previously published analysis for VCl2. The structure of the vanadium dichloride dimer has also been calculated. According to our joint ED and computational study, the evaporation of a solid sample of VCl2 resulted in about 66% vanadium trichloride and 34% vanadium dichloride in the vapor. Vanadium dichloride is unambiguously linear in its 4Sigma(g)+ ground electronic state. For VCl3, all computations yielded a Jahn-Teller-distorted ground-state structure of C(2v) symmetry. However, it lies merely less than 3 kJ/mol lower than the 3E'' state (D(3h) symmetry). Due to the dynamic nature of the Jahn-Teller effect in this case, rigorous distinction cannot be made between the planar models of either D(3h) symmetry or C(2v) symmetry for the equilibrium structure of VCl3. Furthermore, the presence of several low-lying excited electronic states of VCl3 is expected in the high-temperature vapor. To our knowledge, this is the first experimental and computational study of the VCl3 molecule.

Signatures of non-adiabatic dynamics in the fine-structure state distributions of the OH( X ˜ / A ˜ ) products in the B-band photodissociation of H2O

NASA Astrophysics Data System (ADS)

Zhou, Linsen; Xie, Daiqian; Guo, Hua

2015-03-01

A detailed quantum mechanical characterization of the photodissociation dynamics of H2O at 121.6 nm is presented. The calculations were performed using a full-dimensional wave packet method on coupled potential energy surfaces of all relevant electronic states. Our state-to-state model permits a detailed analysis of the OH( X ˜ / A ˜ ) product fine-structure populations as a probe of the non-adiabatic dissociation dynamics. The calculated rotational state distributions of the two Λ-doublet levels of OH( X ˜ , v = 0) exhibit very different characteristics. The A' states, produced mostly via the B ˜ → X ˜ conical intersection pathway, have significantly higher populations than the A″ counterparts, which are primarily from the B ˜ → A ˜ Renner-Teller pathway. The former features a highly inverted and oscillatory rotational state distribution, while the latter has a smooth distribution with much less rotational excitation. In good agreement with experiment, the calculated total OH( X ˜ ) rotational state distribution and anisotropy parameters show clear even-odd oscillations, which can be attributed to a quantum mechanical interference between waves emanating from the HOH and HHO conical intersections in the B ˜ → X ˜ non-adiabatic pathway. On the other hand, the experiment-theory agreement for the OH( A ˜ ) fragment is also satisfactory, although some small quantitative differences suggest remaining imperfections of the ab initio based potential energy surfaces.

Experimental and Computational Investigations of the Threshold Photoelectron Spectrum of the HCCN Radical

NASA Astrophysics Data System (ADS)

Gans, B.; Falvo, Cyril; Coudert, L. H.; Garcia, Gustavo A.; Küger, J.; Loison, J.-C.

2017-06-01

The HCCN radical, already detected in the interstellar medium, is also important for nitrile chemistry in Titan's atmosphere. Quite recently the photoionization spectrum of the radical has been recorded using mass selected threshold photoelectron (TPE) spectroscopy and this provided us with the first spectroscopic information about the HCCN} cation. Modeling such a spectrum requires accounting for the non-rigidity of HCCN and for the Renner-Teller effect in HCCN+. In its ^3A'' electronic ground state, HCCN is a non-rigid molecule as the potential for the \\angle{HCC} bending angle is very shallow. Vibronic couplings with the same bending angle leads, in the ^2Π electronic ground state of HCCN+, to a strong Renner-Teller effect giving rise to a bent ^2A' and a quasi-linear ^2A'' state. In this paper the photoionization spectrum of the HCCN radical is simulated. The model developped treats the \\angle{HCC} bending angle as a large amplitude coordinate in both the radical and the cation and accounts for the overall rotation and the Renner-Teller couplings. Gaussian quadrature are used to calculate matrix elements of the three potential energy functions retrieved through ab initio calculations and rovibrational operators going to infinity for the linear configuration are treated rigorously. The HCCN TPE spectrum is computed with the above model calculating all rotational components and choosing the appropriate lineshape. This synthetic spectrum will be shown in the paper and compared with the experimental one.^b Guélin and Cernicharo, A&A 244 (1991) L21 Loison et al., Icarus 247 (2015) 218 Garcia, Krüger, Gans, Falvo, Coudert, and Loison, J. Chem. Phys. (2017) submitted Koput, J. Phys. Chem. A 106 (2002) 6183 Zhao, Zhang, and Sun, J. Phys. Chem. A 112 (2008) 12125

Re-evaluating reaction rates relevant to nova nucleosynthesis from a nuclear structure perspective

NASA Astrophysics Data System (ADS)

Jenkins, D. G.; Lister, C. J.; Janssens, R. V. F.; Khoo, T. L.; Moore, E. F.; Rehm, K. E.; Seweryniak, D.; Wuosmaa, A. H.; Davinson, T.; Woods, P. J.; Jokinen, A.; Penttila, H.; Martınez-Pinedo, G.; Jose, J.

2006-03-01

Conventionally, reaction rates relevant to nova nucleosynthesis are determined by performing the relevant proton capture reactions directly for stable species, or as has become possible more recently in inverse kinematics using short-lived accelerated radioactive beams with recoil separators. A secondary approach is to compile information on the properties of levels in the Gamow window using transfer reactions. We present a complementary technique where the states of interest are populated in a heavy-ion fusion reaction and their gamma decay studied with a state-of-the-art array of high-purity germanium detectors. The advantages of this approach, including the ability to determine resonance energies with high precision and the possibility of determining spins and parities from gamma-ray angular distributions are discussed. Two specific examples related to the 22Na(p,γ) and 30P(p,γ) reactions are presented.

The strength of electron electron correlation in Cs3C60

NASA Astrophysics Data System (ADS)

Baldassarre, L.; Perucchi, A.; Mitrano, M.; Nicoletti, D.; Marini, C.; Pontiroli, D.; Mazzani, M.; Aramini, M.; Riccó, M.; Giovannetti, G.; Capone, M.; Lupi, S.

2015-10-01

Cs3C60 is an antiferromagnetic insulator that under pressure (P) becomes metallic and superconducting below Tc = 38 K. The superconducting dome present in the T - P phase diagram close to a magnetic state reminds what found in superconducting cuprates and pnictides, strongly suggesting that superconductivity is not of the conventional Bardeen-Cooper-Schrieffer (BCS) type We investigate the insulator to metal transition induced by pressure in Cs3C60 by means of infrared spectroscopy supplemented by Dynamical Mean-Field Theory calculations. The insulating compound is driven towards a metallic-like behaviour, while strong correlations survive in the investigated pressure range. The metallization process is accompanied by an enhancement of the Jahn-Teller effect. This shows that electronic correlations are crucial in determining the insulating behaviour at ambient pressure and the bad metallic nature for increasing pressure. On the other hand, the relevance of the Jahn-Teller coupling in the metallic state confirms that phonon coupling survives in the presence of strong correlations.

Photodissociation of water. II. Wave packet calculations for the photofragmentation of H2O and D2O in the B˜ band

NASA Astrophysics Data System (ADS)

van Harrevelt, Rob; van Hemert, Marc C.

2000-04-01

A complete three-dimensional quantum mechanical description of the photodissociation of water in the B˜ band, starting from its rotational ground state, is presented. In order to include B˜-X˜ vibronic coupling and the B˜-Ã Renner-Teller coupling, diabatic electronic states have been constructed from adiabatic electronic states and matrix elements of the electronic angular momentum operators, following the procedure developed by A. J. Dobbyn and P. J. Knowles [Mol. Phys. 91, 1107 (1997)], using the ab initio results discussed in the preceding paper. The dynamics is studied using wave packet methods, and the evolution of the time-dependent wave function is discussed in detail. Results for the H2O and D2O absorption spectra, OH(A)/OH(X) and OD(A)/OD(X) branching ratios, and rovibrational distributions of the OH and OD fragments are presented and compared with available experimental data. The present theoretical results agree at least qualitatively with the experiments. The calculations show that the absorption spectrum and the product state distributions are strongly influenced by long-lived resonances on the adiabatic B˜ state. It is also shown that molecular rotation plays an important role in the photofragmentation process, due to both the Renner-Teller B˜-X˜ mixing, and the strong effect of out-of-plane molecular rotations (K>0) on the dynamics at near linear HOH and HHO geometries.

Developments for the 6He beta - nu angular correlation experiment

NASA Astrophysics Data System (ADS)

Zumwalt, David W.

This thesis describes developments toward the measurement of the angular correlation between the beta and the antineutrino in the beta decay of 6He. This decay is a pure Gamow-Teller decay which is described in the Standard Model as a purely axial vector weak interaction. The angular correlation is characterized by the parameter abetanu = -1/3 in the Standard Model. Any deviation from this value would be evidence for tensor components in the weak interaction and would constitute new physics. A new method will be used to measure the parameter a betanu from 6He decays, featuring a magneto-optical trap that will measure the beta particle in coincidence with the recoiling 6Li daughter ion. This neutral atom trapping scheme provides cold, tightly confined atoms which will reduce systematic uncertainties related to the initial position of the decay. By knowing the initial position of the decay and measuring the time of flight of the recoiling 6Li daughter ion in coincidence with the beta, the angular correlation between the beta and the antineutrino can be deduced. We aim to measure a betanu first to the level of 1%, and eventually to the 0.1% level, which would represent an order of magnitude improvement in precision over past experiments. Towards this goal, we have designed, built, and successfully tested a liquid lithium target to provide >2×10. {10} 6He atoms/sto a low-background environment, which is the most intense source of 6He presently available. This allowed for an additional measurement of the 6He half-life (806.89 +/- 0.11stat +0.23-0.19syst ms) to be made with unprecedented precision, resolving discrepancies in past measurements. We have also tested our trapping and detection apparatus and have begun to record preliminary coincidence events.

Spectroscopy and heats of formation of CXI (X = Br, Cl, F) iodocarbenes: quantum chemical characterisation of the ?, ? and ? states

NASA Astrophysics Data System (ADS)

Bacskay, George B.

2015-07-01

The equilibrium energies of the iodocarbenes CXI (X = Br, Cl, F) in their ?, ? and ? states and their atomisation and dissociation energies in the complete basis limit were determined by extrapolating valence correlated (R/U)CCSD(T) and Davidson corrected multi-reference configuration interaction (MRCI) energies calculated with the aug-cc-pVxZ (x = T,Q,5) basis sets and the ECP28MDF pseudopotential of iodine plus corrections for core and core-valence correlation, scalar relativity, spin-orbit coupling and zero-point energies. Spin-orbit energies were computed in a large basis of configurations chosen so as to accurately describe dissociation to the 3P and 2P states of C and of the halogens X and I, respectively. The computed singlet-triplet splittings are 13.6, 14.4 and 27.3 kcal mol-1 for X = Br, Cl and F, respectively. The enthalpies of formation at 0 K are predicted to be 97.4, 82.6 and 38.1 kcal mol-1 with estimated errors of ±1.0 kcal mol-1. The ? excitation energies (T00) in CBrI and CClI are calculated to be 41.1 and 41.7 kcal mol-1, respectively. The Renner-Teller intersections in both molecules are predicted to be substantially higher than the dissociation barriers on the ? surfaces. By contrast, in CFI the ? state is found to be unbound with respect to dissociation.

Magnetization and heat-capacity measurements on Zn1-xCrxTe

NASA Astrophysics Data System (ADS)

Pekarek, T. M.; Luning, J. E.; Miotkowski, I.; Crooker, B. C.

1994-12-01

We have taken magnetization and calorimetric measurements on Zn1-xCrxTe (x=0.003). The heat-capacity measurements show a Schottky peak indicating an energy-level splitting of 3.1 K between the ground and first excited states. Above 1.5 K we observe additional heat capacity, which indicates the presence of additional low-energy vibronic excitations. The magnetization data reveal a small anisotropy (~7%) with the (111) direction giving the largest value. The magnetization data were fit with a model including a static Jahn-Teller distortion proposed previously in these materials [J. T. Vallin, G. A. Slack, S. Roberts, and A. E. Hughes, Phys. Rev. B 2, 4313 (1970)]. Reasonable agreement was found with the data for a spin-orbit parameter of -59 cm-1 and a Jahn-Teller energy of 320 cm-1.

Teller Award acceptance speech

NASA Astrophysics Data System (ADS)

Kirillov, Gennady A.

Since I am not good at speaking English, I would like to ask Dr.Kochemasov to translate my Russian. Here I would like to talk shortly about studies on ion-laser physics at Arzamas-16. We have begun these investigations since 1965. The group was under the leadership of Khariton and Kohmir, and I was one of the active scientists. In the beginning, the research was proceeded in collaboration with Basov and Krohkin at Levedev institute. In 1961, it was reported that in terms of molecular dissociation it is possible to achieve inversion population. It was 1965 when a practical ion-laser system was first realized. We then got started on the research with the following experimental set up. First, a crystal tube was filled with xenon gas. Then, by means of a high explosive a strong shock wave was launched. The shock wave propagated along the tube. The radiation temperature observed was as high as 46,000C. Through the experiments, we could obtain various dependencies of physical quantities under different conditions. In the end, we could develop a laser system without using the crystal tube. The laser was further improved by changing the configuration of the surrounding explosives. As a result, laser energy of 100 kJ was successfully extracted at the quantum efficiency of about 100%.

Anisotropic orbital occupation and Jahn-Teller distortion of orthorhombic YMnO{sub 3} epitaxial films: A combined experimental and theoretical study on polarization-dependent x-ray absorption spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haw, Shu-Chih; Chen, Shin-Ann; National Synchrotron Radiation Research Center

2014-04-21

The b-axis oriented orthorhombic YMnO{sub 3} (o-YMnO{sub 3}) epitaxial films on a YAlO{sub 3} (010) substrate were fabricated with pulsed-laser deposition. The anisotropic orbital occupation and Jahn-Teller (JT) distortion of an o-YMnO{sub 3} film were investigated with polarization-dependent x-ray absorption spectra and configuration-interaction multiplet-cluster calculations. A significant energy difference, ∼3.8 eV, for the main white line along E//b and E//a in polarization-dependent Mn K-edge spectra of o-YMnO{sub 3} indicates an extraordinary JT distortion and significant anisotropic Mn–O bonding within the ab plane in the o-YMnO{sub 3} film. Most importantly, although the orbital occupation of 3d electrons in o-YMnO{sub 3} filmsmore » is almost the same as that in single crystalline o-DyMnO{sub 3}, the JT distortion of o-YMnO{sub 3} films is larger than that of single crystalline o-DyMnO{sub 3}, deduced from the multiplet calculations. We speculate that this JT distortion predominantly contributes to the origin of the cycloidal spin deformation in bulk o-YMnO{sub 3}, because of a suppressed nearest-neighbor superexchange interaction and an enhanced next-nearest-neighbor superexchange interaction. These complementary results provide insight into the origin of the E-type magnetic configuration of o-YMnO{sub 3}.« less

Many-body interactions and high-pressure equations of state in rare-gas solids

NASA Astrophysics Data System (ADS)

Freiman, Yu. A.; Tretyak, S. M.

2007-06-01

The T =0K equations of state (EOS) of rare-gas solids (RGS) (He, Ne, Ar, Kr, and Xe) are calculated in the experimentally studied ranges of pressures with the two- and three-body interatomic forces taken into account. Solid-state corrections to the pure two-body Aziz et al. potentials included the long-range Axilrod-Teller three-body interaction and short-range three-body exchange interaction. The energy-scale and length-scale parameters of the latter were taken as adjustable parameters of theory. The calculated T =0K EOS for all RGS are in excellent agreement with experiment in the whole range of pressures. The calculated EOS for Ar, Kr, and Xe exhibit inflection points where the isothermal bulk moduli have non-physical maxima, indicating that account of only three-body forces becomes insufficient. These points lie at pressures 250, 200, and 175GPa (volume compressions of approximately 4.8, 4.1, and 3.6) for Ar, Kr, and Xe, respectively. No such points were found in the calculated EOS of He and Ne. The relative magnitude of the three-body contribution to the ground-state energy with respect to the two-body one as a function of the volume compression was found to be nonmonotonic in the sequence Ne-Ar-Kr-Xe. In a large range of compressions, Kr has the highest value of this ratio. This anomalously high three-body exchange force contributes to the EOS a negative pressure so large that the EOS for Kr and Ar as a function of compression nearly coincide. At compressions higher than approximately 3.5 the curves intersect, and further on, the EOS of Kr lies lower than that of Ar.

On scattering from the one-dimensional multiple Dirac delta potentials

NASA Astrophysics Data System (ADS)

Erman, Fatih; Gadella, Manuel; Uncu, Haydar

2018-05-01

In this paper, we propose a pedagogical presentation of the Lippmann–Schwinger equation as a powerful tool, so as to obtain important scattering information. In particular, we consider a one-dimensional system with a Schrödinger-type free Hamiltonian decorated with a sequence of N attractive Dirac delta interactions. We first write the Lippmann–Schwinger equation for the system and then solve it explicitly in terms of an N × N matrix. Then, we discuss the reflection and the transmission coefficients for an arbitrary number of centres and study the threshold anomaly for the N = 2 and N = 4 cases. We also study further features like the quantum metastable states and resonances, including their corresponding Gamow functions and virtual or antibound states. The use of the Lippmann–Schwinger equation simplifies our analysis enormously and gives exact results for an arbitrary number of Dirac delta potentials.

Alpha-capture reaction rates for 22Ne(alpha,n) via sub-Coulomb alpha-transfer

NASA Astrophysics Data System (ADS)

Jayatissa, Heshani; Rogachev, Grigory; Koshchiy, Yevgen; Goldberg, Vladilen; Bedoor, Shadi; Hooker, Joshua; Hunt, Curtis; Magana, Cordero; Roeder, Brian; Saastamoinen, Antti; Spiridon, Alexandria; Upadhyayula, Sriteja

2016-09-01

Direct measurements of α-capture reactions at energies relevant to astrophysics is extremely difficult to carry out due to the very small reaction cross section. The large uncertainties introduced when extrapolating direct measurements at high energies down to the Gamow energies can be overcome by measuring the Asymptotic Normalization Coefficients (ANC) of the relevant states using (6Li,d) α-transfer reactions at sub-Coulomb energies to reduce the model dependence. The study of the 22Ne(6Li,d) reaction was carried out at the Cyclotron Institute at Texas A&M University. The α-ANC measurements for the near α-threshold resonances of 26Mg will provide constraints for the reaction rate of the 22Ne(α,n) reaction.

Aggregate frequency width, nuclear hyperfine coupling and Jahn-Teller effect of Cu2+ impurity ion ESR in SrLaAlO4 dielectric resonator at 20 millikelvin

NASA Astrophysics Data System (ADS)

Hosain, M. A.; Le Floch, J.-M.; Krupka, J.; Tobar, M. E.

2018-01-01

The impurity paramagnetic ion, Cu2+ substitutes Al in the SrLaAlO4 single crystal lattice, this results in a CuO6 elongated octahedron, and the resulting measured g-factors satisfy four-fold axes variation condition. The aggregate frequency width of the electron spin resonance with the required minimum level of impurity concentration has been evaluated in this single crystal SrLaAlO4 at 20 millikelvin. Measured parallel hyperfine constants, A\\Vert Cu , were determined to be -155.7×10-4~cm-1, ~ -163.0×10-4~cm-1, ~ -178.3×10-4~cm-1 and -211.1×10-4~cm-1 at 9.072~GHz~(WGH4, 1, 1) for the nuclear magnetic quantum number M_I=+\\frac{3}{2}, +\\frac{1}{2}, -\\frac{1}{2} , and -\\frac{3}{2} respectively. The anisotropy of the hyperfine structure reveals the characteristics of the static Jahn-Teller effect. The second-order-anisotropy term, ˜ (\\fracspin{-orbit~coupling}{10D_q}){\\hspace{0pt}}2 , is significant and cannot be disregarded, with the local strain dominating over the observed Zeeman-anisotropy-energy difference. The Bohr electron magneton, β=9.23× 10-24 JT-1 , (within -0.43% so-called experimental error) has been found using the measured spin-Hamiltonian parameters. Measured nuclear dipolar hyperfine structure parameter P\\Vert=12.3×10-4~cm-1 shows that the mean inverse third power of the electron distance from the nucleus is < r-3_q>≃ 5.23 a.u. for Cu2+ ion in the substituted Al3+ ion site assuming nuclear electric quadruple moment Q=-0.211 barn.

Cobalt terephthalate MOF-templated synthesis of porous nano-crystalline Co3O4 by the new indirect solid state thermolysis as cathode material of asymmetric supercapacitor

NASA Astrophysics Data System (ADS)

Bigdeli, Hadise; Moradi, Morteza; Hajati, Shaaker; Kiani, Mohammad Ali; Toth, Jozsef

2017-10-01

In this work, two different types of Co3O4 nano-crystals were synthesized by (i) conventional direct solid state thermolysis of cobalt terephthalate metal-organic framework (MOF-71) and (ii) new indirect solid state thermolysis of Co(OH)2 derived by alkaline aqueous treatment of MOF-71. The products were then characterized by X-ray diffraction technique (XRD), Fourier transforms infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Reflection electron energy loss spectroscopy (REELS), Brunauer, Emmett, and Teller (BET), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. By REELS analysis the energy band gap of MOF-71 was determined to be 3.7 eV. Further, electrochemical performance of each Co3O4 nanostructure was studied by the cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in a three-electrode system in KOH electrolyte. An asymmetric supercapacitor was fabricated using indirect Co3O4 nanoparticles as cathode and electrochemically reduced graphene oxide as anode, and the electrochemical properties were studied and showed a high energy density of 13.51 Wh kg-1 along with a power density of 9775 W kg-1 and good cycling stability with capacitance retention rate of 85% after 2000 cycles.

Angle-resolved photoelectron spectroscopy of cyclopropane

NASA Astrophysics Data System (ADS)

Keller, P. R.; Taylor, J. W.; Carlson, Thomas A.; Whitley, T. A.; Grimm, F. A.

1985-10-01

The angular distribution parameter, β, determined for the valence orbitals (IP < 18 eV) of cyclopropane in the 10-30 eV photon energy range using dispersed polarized synchrotron radiation. The energy dependence of β for photoelectron energies between, 2 and 10 eV above threshold was found to be similar to those found previously for other σ orbitals. The effects of Jahn-Teller splitting on β for the 3e' orbital were found to be small but definitely present. The overall shape and magnitude of the β( hv) curve are, however, sufficiently for the different Jahn-Teller components that, for purposes of orbital assignments using β( hv) curves the shape and magnitude of the curves can be considered associated only with the initial state. Resonance photoionization features at a photon ener of ≈ 18 eV were observed in the 3e' and 3a' 1 orbitals and tentatively assigned to autoionization.

Spin glass behavior in frustrated quantum spin system CuAl 2 O 4 with a possible orbital liquid state

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nirmala, R.; Jang, Kwang-Hyun; Sim, Hasung

2017-02-15

CuAl 2O 4 is a normal spinel oxide having quantum spin, S = 1/2 for Cu 2+. It is a rather unique feature that the Cu 2+ ions of CuAl 2O 4 sit at a tetrahedral position, not like the usual octahedral position for many oxides. At low temperatures, it exhibits all the thermodynamic evidence of a quantum spin glass. For example, the polycrystalline CuAl 2O 4 shows a cusp centered at ~2 K in the low-field dc magnetization data and a clear frequency dependence in the ac magnetic susceptibility while it displays logarithmic relaxation behavior in a time dependencemore » of the magnetization. At the same time, there is a peak at ~2.3 K in the heat capacity, which shifts towards a higher temperature with magnetic fields. Conversely, there is no evidence of new superlattice peaks in the high-resolution neutron powder diffraction data when cooled from 40 to 0.4 K. This implies that there is no long-ranged magnetic order down to 0.4 K, thus confirming a spin glass-like ground state for CuAl 2O 4. Interestingly, there is no sign of structural distortion either although Cu 2+ is a Jahn–Teller active ion. Therefore, we claim that an orbital liquid state is the most likely ground state in CuAl 2O 4. Of further interest, it also exhibits a large frustration parameter, f = |θ CW/T m| ~ 67, one of the largest values reported for spinel oxides. These observations suggest that CuAl 2O 4 should be a rare example of a frustrated quantum spin glass with a good candidate for an orbital liquid state.« less

Pulp science: education and communication in the paperback book revolution.

PubMed

Gormley, Melinda

2016-03-01

Paperback books on scientific topics were a hot commodity in the United States from the 1940s to 1960s providing a vehicle for science communication that transformed science education. Well-known scientists authored them, including Rachel Carson, Theodosius Dobzhansky, George Gamow, Fred Hoyle, Julian Huxley, and Margaret Mead. A short history of 'the paperback revolution' that began in the 1930s is provided before concentrating on one publishing company based in New York City, the New American Library of World Literature (NAL), which produced Signet and Mentor Books. The infrastructure that led to the production and consumption of paperback books is described and an underexplored and not-previously identified genre of educational books on scientific topics, what the author refers to as pulp science, is characterized. Copyright © 2016 Elsevier Ltd. All rights reserved.

Linking Bakhtin with feminist poststructuralism to unravel the allure of auto/biographies

NASA Astrophysics Data System (ADS)

Rodriguez, Alberto J.

2000-03-01

By linking feminist poststructuralism with Bakhtin's concepts of voice and ventriloquation, an approach is proposed for the critical engagement with auto/biographical text. It is argued that by becoming better aware of the teller's intentionality and her/his insights gained from telling a (re)constructed version of self, the listener and the teller can engage in personal and socially transformative dialog. This dialog can assist the teller/listener to move from superficial affirmation of (re)interpreted lived experiences to more socially responsive action. An example is provided to illustrate implications of this approach for science teaching and education research.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chinn, D J

This month's issue has the following articles: (1) The Edward Teller Centennial--Commentary by George H. Miller; (2) Edward Teller's Century: Celebrating the Man and His Vision--Colleagues at the Laboratory remember Edward Teller, cofounder of Lawrence Livermore, adviser to U.S. presidents, and physicist extraordinaire, on the 100th anniversary of his birth; (3) Quark Theory and Today's Supercomputers: It's a Match--Thanks to the power of BlueGene/L, Livermore has become an epicenter for theoretical advances in particle physics; and (4) The Role of Dentin in Tooth Fracture--Studies on tooth dentin show that its mechanical properties degrade with age.

Magneto-structural correlation in Co0.8Cu0.2Cr2O4 cubic spinel

NASA Astrophysics Data System (ADS)

Kumar, Ram; Rayaprol, S.; Siruguri, V.; Xiao, Y.; Ji, W.; Pal, D.

2018-05-01

Neutron and X-ray diffraction, magnetic susceptibility, and specific heat measurements have been used to investigate the magneto-structural phase transitions in 20% Cu substituted multiferroic CoCr2O4 spinel. The Jahn-Teller active Cu2+ ion in the tetrahedral A-site of the spinel configuration induces the Jahn-Teller distortion slightly above the Néel temperature. In this compound, we observe a Jahn-Teller distortion of the crystal structure at 90 K. It was further observed that the high temperature cubic (Fd 3 ‾ m) structure coexists with the low temperature orthorhombic (Fddd) structure till the lowest temperature of measurement.

Isospin mixing reveals 30P(p, γ) 31S resonance influencing nova nucleosynthesis

DOE PAGES

Bennett, M. B.; Wrede, C.; Brown, B. A.; ...

2016-03-08

Here, the thermonuclear 30P(p, γ) 31S reaction rate is critical for modeling the final elemental and isotopic abundances of ONe nova nucleosynthesis, which affect the calibration of proposed nova thermometers and the identification of presolar nova grains, respectively. Unfortunately, the rate of this reaction is essentially unconstrained experimentally, because the strengths of key 31S proton capture resonance states are not known, largely due to uncertainties in their spins and parities. Using the β decay of 31Cl, we have observed the β-delayed γ decay of a 31S state at E x = 6390.2(7) keV, with a 30P(p, γ) 31S resonance energymore » of E r = 259.3(8) keV, in the middle of the 30P(p, γ) 31S Gamow window for peak nova temperatures. This state exhibits isospin mixing with the nearby isobaric analog state at E x = 6279.0(6) keV, giving it an unambiguous spin and parity of 3/2 + and making it an important l = 0 resonance for proton capture on 30P.« less

Cosmic Microwave Background Timeline

Science.gov Websites

about 2.3 K 1948: George Gamow, Ralph Alpher, and Robert Herman predict that a Big Bang universe perfect blackbody spectrum and thereby strongly supporting the hot big bang model, the thermal history of anisotropy in the cosmic microwave background, this strongly supports the big bang model with gravitational

A survey of ab initio conical intersections for the H+H2 system

NASA Astrophysics Data System (ADS)

Halász, Gábor; Vibók, Ágnes; Mebel, Alexander M.; Baer, Michael

2003-02-01

In this article we present a survey of the various conical intersections which govern potential transitions between the three lower electronic states for the title molecular system. It was revealed that these three states, for a given fixed HH distance, RHH, usually form four conical intersections: two, between the two lower states and two, between the two upper states. One of the four is the well known equilateral D3h ci and the others are, essentially, C2v cis: One of them is located on the symmetry line perpendicular to the HH axis (just like the D3h ci) and the other two are located on both sides of this symmetry line and in this way form the ci-twins. The study was carried out for four RHH-values, namely, RHH=0.74, 0.5417, 0.52, and 0.4777 Å. It was also established that there exists one single RHH-value designated as R˜HH, located in the interval {0.52, 0.53 Å}, for which all four cis coalesce to become one kind of "super" ci which couples the three states. The numerical study was carried out employing the line integral approach for groups of two and three states. As for the two-state calculations we found that all D3h-cis, at close proximity, are circular (ordinary) Jahn-Teller-type cis, whereas all C2v-cis, at close proximity, are elliptic Jahn-Teller cis [Chem. Phys. Lett 354, 243 (2002)]. Particular attention is given to the 3-state quantization of the nonadiabatic coupling matrix. The quantization is found to be fulfilled in all situations as long as the regions in configuration space are not too far from the relevant cis. In the Discussion and Conclusion we discuss, among other subjects, the possibility to diabatize the adiabatic potential matrix.

COMPARATIVE STUDY ON THE LEVEL OF BACTERIOLOGICAL CONTAMINATION OF AUTOMATIC TELLER MACHINES, PUBLIC TOILETS AND PUBLIC TRANSPORT COMMERCIAL MOTORCYCLE CRASH HELMETS IN KIGALI CITY, RWANDA.

PubMed

Nigatu, W; Fabiola, N S; Flora, I J; Mukahirwa, M A; Omar, M; Nsengimana, J; Nsabimana, A

2014-12-01

The environments can be contaminated by infectious agents that constitute a major health hazards as sources of community and hospital-acquired infections due to various activities. A comparative study on the level of bacteriological contamination of automatic teller machines (ATMs), public toilets and commercial motorcycle crash helmets were conducted in Kigali city during the period of January to March, 2013. Samples were collected from selected ATMs, public toilets and commercial motorcycle crash helmets surfaces. Micro-organisms identified from these samples were associated to infecting organisms recovered from unwashed hands surfaces and recorded results in the nearby hospital. Samples from each device and subject were transported to the laboratory where they were analysed for the presence of coliforms and other airborne, human skin and intestinal disease causing microorganisms. Microbiological methods including spread plate techniques and some biochemical tests were used to partially identify the microorganisms. Subjects involved in this study were consented students from University of Rwanda and Kigali motorcyclists for collections of samples from hands and crash helmets respectively. The following pathogenic bacteria have been found on the devices, Staphylococcus aureus, Staphylococcus epidermis, Streptococcus species, Escherichia coli, Salmonella, Klebsiella, Enterobacter aerogenes, Pseudomonas. The commercial motorcycle crash helmets had the highest level of bacteriological contamination compared to ATMs and public toilets. There was no growth observed on samples collected after treatment from ATMs, public toilets, and commercial motorcycle crash helmets. Attempt to correlate this finding with infecting organisms recovered from unwashed hands surfaces and recorded results in the nearby hospital show that the presences of some of these infectious pathogens. This study has revealed the ability of these public devices to serve as vehicle of transmission of

Surface Meteorology at Kougarok Site Station, Seward Peninsula, Alaska, Ongoing from 2017

DOE Data Explorer

Bob Busey; Bob Bolton; Cathy Wilson; Lily Cohen

2017-12-04

Meteorological data are currently being collected at one location at the top of the Kougarok hill, Seward Peninsula. This December 18, 2017 release includes data for: Teller Creek Station near TL_BSV (TELLER BOTTOM METEOROLOGICAL STATION) Station is located in the lower watershed in a tussock / willow transition zone and co-located with continuous snow depth measurements and subsurface measurements. Teller Creek Station near TL_IS_5 (TELLER TOP METEOROLOGICAL STATION) Station is located in the upper watershed and co-located with continuous snow depth measurements and subsurface measurements. Two types of data products are provided for these stations: First, meteorological and site characterization data grouped by sensor/measurement type (e.g., radiation or soil pit temperature and moisture). These are *.csv files. Second, a Data Visualization tool is provided for quick visualization of measurements over time at a station. Download the *_Visualizer.zip file, extract, and click on the 'index.html' file. Data values are the same in both products.

BOOK REVIEW: Conversations on the Dark Secrets of Physics

NASA Astrophysics Data System (ADS)

Teller, Edward

2003-07-01

Over many years Edward Teller delivered a course of Physical Science Appreciation Lectures. This book is based on those lectures, which must have been very stimulating. In the preparation of the book, Edward Teller was assisted by his daughter, Wendy Teller, and also by Wilson Talley. On many pages there are footnotes in the form of conversations between 'ET', who explains, and 'WT', who asks intelligent questions. (It is never clear which 'WT' is which.) I mention these footnotes as they contribute enormously to the charm and humour of the book. The book contains numerous anecdotes, many of which were new to me. The verse in the New Yorker, by Harold Furth, recording the famous meeting between Dr Teller and Dr Anti-Teller, is included. Dr Teller's comment is `The remarkable fact is that Harold got paid for the poem'. Dr Anti-Teller's comment is anti-recorded. The topics in the book include simple mechanics, statistical mechanics, electromagnetism, quantum mechanics and 'uses of new knowledge'. Despite its origins, the book does not avoid mathematics ('I will use mathematics because physics without mathematics is meaningless' (p1)), but Teller does attempt to explain the mathematics he uses. In much of the book the mathematics is at school level, but in his treatment of quantum mechanics he uses differential equations. If one skips past the equations then his final chapters are less mathematically demanding. I have enjoyed reading this book. Teller's approach is refreshing, and his coverage comprehensive and generally authoritative. My only disquiet is over his coverage of electrons in solids, where it would be clearer to consider the one-dimensional case first, before treating the three-dimensional case. There is a substantial discussion on the correspondence principle, wave-particle duality and on the uncertainty principle. His disposal of Schrödinger's notorious cat is masterly. There are questions at the end of each chapter. One question is based on a possible

Synthesis of ternary oxide for efficient photo catalytic conversion of CO2

NASA Astrophysics Data System (ADS)

Wan, Lijuan

2018-01-01

Zn2GeO4 Nan rods were prepared by solution phase route. The morphology and structure of the as-prepared products were characterized by scanning electron microscopy (SEM) and Bruner-Emmett-Teller (BET) surface area measurements. The results revealed that Zn2GeO4 Nan rods with higher surface area have higher photo catalytic activity in photo reduction of CO2 than Zn2GeO4 prepared through solid-state reaction.

Proceedings of an AAAS Symposium on January 8, 1980: How Much does the Defense Department Advance Science?

DTIC Science & Technology

1980-09-24

DEFENSE OF FREEDOM 18 Edward Teller DANGERS OF USING SCIENCE FOR THE ARMS BUSINESS IN A CORPORATE STATE 21 George Wald DISCUSSION . 25...many other questions. Does the Don’s basic-research program oversupport research which is oriented to the solution of applied problems? Has DOD...long-range goal of being technologically superior in the world. We would be very short-sighted if our program was directed only to the solution of

Mosaicked Historic Airborne Imagery from Seward Peninsula, Alaska, Starting in the 1950's

DOE Data Explorer

Cherry, Jessica; Wirth, Lisa

2016-12-06

Historical airborne imagery for each Seward Peninsula NGEE Arctic site - Teller, Kougarok, Council - with multiple years for each site. This dataset includes mosaicked, geolocated and, where possible, orthorectified, historic airborne and recent satellite imagery. The older photos were sourced from USGS's Earth Explorer site and the newer, satellite imagery is from the Statewide Digital Mapping Initiative (SDMI) project managed by the Geographic Information Network of Alaska on behalf of the state of Alaska.

Non percolative nature of the metal-insulator transition and persistence of local Jahn-Teller distortions in the rhombohedral regime of La 1-xCa xMnO 3

DOE PAGES

Shatnawi, Mouath; Bozin, Emil S.; Mitchell, J. F.; ...

2016-04-25

Evolution of the average and local crystal structure of Ca-doped LaMnO 3 has been studied across the metal to insulator (MI) and the orthorhombic to rhombohedral (OR) structural phase transitions over a broad temperature range for two Ca concentrations (x = 0.18,0.22). Combined Rietveld and high real space resolution atomic pair distribution function (PDF) analysis of neutron total scattering data was carried out with aims of exploring the possibility of nanoscale phase separation (PS) in relation to MI transition, and charting the evolution of local Jahn-Teller (JT) distortion of MnO 6 octahedra across the OR transition at T S~720 K.more » The study utilized explicit two-phase PDF structural modeling, revealing that away from T MI there is no evidence for nanoscale phase coexistence. The local JT distortions disappear abruptly upon crossing into the metallic regime both with doping and temperature, with only a small temperature-independent signature of quenched disorder being observable at low temperature as compared to CaMnO 3. The results hence do not support the percolative scenario for the MI transition in La 1–xCa xMnO 3 based on PS, and question its ubiquity in the manganites. In contrast to LaMnO 3 that exhibits long-range orbital correlations and sizable octahedral distortions at low temperature, the doped samples with compositions straddling the MI boundary exhibit correlations (in the insulating regime) limited to only ~1 nm with observably smaller distortions. In the x = 0.22 sample local JT distortions are found to persist across the OR transition and deep into the R phase (up to ~1050 K), where they are crystallographically prohibited. As a result, their magnitude and subnanometer spatial extent remain unchanged.« less

Phase Separation and d Electronic Orbitals on Cyclic Degradation in Li-Mn-O Compounds: First-Principles Multiscale Modeling and Experimental Observations.

PubMed

Kim, Duho; Lim, Jin-Myoung; Park, Min-Sik; Cho, Kyeongjae; Cho, Maenghyo

2016-07-06

A combined study involving experiments and multiscale computational approaches is conducted to propose a theoretical solution for the suppression of the Jahn-Teller distortion which causes severe cyclic degradation. As-synthesized pristine and Al-doped Mn spinel compounds are the focus to understand the mechanism of the cyclic degradation in terms of the Jahn-Teller distortion, and the electrochemical performance of the Al-doped sample shows enhanced cyclic performance compared with that of the pristine one. Considering the electronic structures of the two systems using first-principles calculations, the pristine spinel suffers entirely from the Jahn-Teller distortion by Mn(3+), indicating an anisotropic electronic structure, but the Al-doped spinel exhibits an isotropic electronic structure, which means the suppressed Jahn-Teller distortion. A multiscale phase field model in nanodomain shows that the phase separation of the pristine spinel occurs to inactive Li0Mn2O4 (i.e., fully delithiated) gradually during cycles. In contrast, the Al-doped spinel does not show phase separation to an inactive phase. This explains why the Al-doped spinel maintains the capacity of the first charge during the subsequent cycles. On the basis of the mechanistic understanding of the origins and mechanism of the suppression of the Jahn-Teller distortion, fundamental insight for making tremendous cuts in the cyclic degradation could be provided for the Li-Mn-O compounds of Li-ion batteries.

Coupled channels description of the α-decay fine structure

NASA Astrophysics Data System (ADS)

Delion, D. S.; Ren, Zhongzhou; Dumitrescu, A.; Ni, Dongdong

2018-05-01

We review the coupled channels approach of α transitions to excited states. The α-decaying states are identified as narrow outgoing Gamow resonances in an α-daughter potential. The real part of the eigenvalue corresponds to the Q-value, while the imaginary part determines the half of the total α-decay width. We first review the calculations describing transitions to rotational states treated by the rigid rotator model, in even–even, odd-mass and odd–odd nuclei. It is found that the semiclassical method overestimates the branching ratios to excited 4+ for some even–even α-emitters and fails in explaining the unexpected inversion of branching ratios of some odd-mass nuclei, while the coupled-channels results show good agreement with the experimental data. Then, we review the coupled channels method for α-transitions to 2+ vibrational and transitional states. We present the results of the Coherent State Model that describes in a unified way the spectra of vibrational, transitional and rotational nuclei. We evidence general features of the α-decay fine structure, namely the linear dependence between α-intensities and excitation energy, the linear correlation between the strength of the α-core interaction and spectroscopic factor, and the inverse correlation between the nuclear collectivity, given by electromagnetic transitions, and α-clustering.

DOD Business Systems Modernization: Planned Investment in Navy Program to Create Cashless Shipboard Environment Needs to Be Justified and Better Managed

DTIC Science & Technology

2008-09-01

Abbreviations ATM automated teller machine BEA business enterprise architecture DOD...Limitations Automated Teller Machines (ATMs)-At-Sea 1988 Localized, shipboard ATMs that received and accounted for a portion of sailors’ and...use smart card technology for electronic retail ransactions and (2) economically justified on the basis of reliable analyses of stimated costs and

Banking and Related Financial Services.

ERIC Educational Resources Information Center

Snyder, Les

This curriculum guide lists competencies for banking and related financial services occupations, validated by educators and experienced persons in the field in Arizona. The competencies describe the skills required of entry-level workers. The guide is in two parts with one focusing on teller or teller-like positions, and the other focusing on…

Storytelling in the Classroom: Some Theoretical Thoughts.

ERIC Educational Resources Information Center

Roney, R. Craig

1996-01-01

In its most basic form, storytelling is a process where a person (the teller), using vocalization, narrative structure, and mental imagery, communicates with the audience who also use mental imagery and, in turn, communicate back to the teller primarily through body language and facial expression in an ongoing communication cycle. Storytelling is…

Origin of a sensitive dependence of calculated {beta}{beta}-decay amplitudes on the particle-particle residual interaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodin, Vadim; Faessler, Amand

2011-07-15

In the present work the sensitivity of calculated {beta}{beta}-decay amplitudes to a realistic residual interaction is analyzed in the framework of the approach of O. A. Rumyantsev and M. H. Urin, Phys. Lett. B 443, 51 (1998). and V. A. Rodin, M. H. Urin, and A. Faessler, Nucl. Phys. A 747, 297 (2005). Both the Gamow-Teller (GT) and Fermi (F) matrix elements M{sup 2}{nu} for two-neutrino {beta}{beta} decay (2{nu}{beta}{beta} decay), along with the monopole transition contributions to the total matrix elements M{sup 0{nu}} of neutrinoless {beta}{beta} decay (0{nu}{beta}{beta} decay), are calculated within the quasiparticle random-phase approximation (QRPA). In the aforementionedmore » approach decompositions of M{sup 2{nu}} and M{sup 0{nu}} can be obtained in terms of the corresponding energy-weighted sum rules S. It is shown that in most of the cases almost the whole dependence of M{sup 2{nu}} and M{sup 0{nu}} on the particle-particle (p-p) renormalization parameter g{sub pp} is accounted for by the g{sub pp} dependence of the corresponding sum rules S. General expressions relating S to a realistic residual particle-particle interaction are derived, which show a pronounced sensitivity of S to the singlet-channel interaction in the case of F transitions and to the triplet-channel interaction in the case of GT transitions. Thus, the sensitivity of M{sup 2{nu}} and M{sup 0{nu}} to the SU(4)-symmetry-breaking part of the p-p residual interaction is dictated by the generic structure of the {beta}{beta}-decay amplitudes. Therefore, a choice of this part in a particular calculation needs a special caution. Finally, a better isospin-consistent way of renormalization of a realistic residual p-p interaction to use in QRPA calculations is suggested.« less

Communicating the science of the 11-year sunspot cycle to the general public

NASA Astrophysics Data System (ADS)

Choudhuri, A. R.

2015-03-01

Astrophysics is one branch of science which excites the imagination of the general public. Pioneer science popularizers like George Gamow and Fred Hoyle wrote on different aspects of astrophysics. However, of late, we see a trend which I find disturbing. While it has become extremely fashionable to write popular science books on cosmology, other areas of astrophysics are grossly neglected.

12 CFR 740.4 - Requirements for the official sign.

Code of Federal Regulations, 2010 CFR

2010-01-01

... and appearing on NCUA's official website, or alter by hand or otherwise the official sign depicted in... directly.” This sign must be similar to the official sign in terms of design, color, and font. (2) A teller... official sign in terms of design, color, and font. (3) A teller in a branch of a nonfederally insured...

Orbital symmetry fingerprints for magnetic adatoms in graphene

NASA Astrophysics Data System (ADS)

Uchoa, Bruno; Yang, Ling; Tsai, S.-W.; Peres, N. M. R.; Castro Neto, A. H.

2014-01-01

In this paper, we describe the formation of local resonances in graphene in the presence of magnetic adatoms containing localized orbitals of arbitrary symmetry, corresponding to any given angular momentum state. We show that quantum interference effects which are naturally inbuilt in the honeycomb lattice in combination with the specific orbital symmetry of the localized state lead to the formation of fingerprints in differential conductance curves. In the presence of Jahn-Teller distortion effects, which lift the orbital degeneracy of the adatoms, the orbital symmetries can lead to distinctive signatures in the local density of states. We show that those effects allow scanning tunneling probes to characterize adatoms and defects in graphene.

Accurate potential energy surface for the 1(2)A' state of NH(2): scaling of external correlation versus extrapolation to the complete basis set limit.

PubMed

Li, Y Q; Varandas, A J C

2010-09-16

An accurate single-sheeted double many-body expansion potential energy surface is reported for the title system which is suitable for dynamics and kinetics studies of the reactions of N(2D) + H2(X1Sigmag+) NH(a1Delta) + H(2S) and their isotopomeric variants. It is obtained by fitting ab initio energies calculated at the multireference configuration interaction level with the aug-cc-pVQZ basis set, after slightly correcting semiempirically the dynamical correlation using the double many-body expansion-scaled external correlation method. The function so obtained is compared in detail with a potential energy surface of the same family obtained by extrapolating the calculated raw energies to the complete basis set limit. The topographical features of the novel global potential energy surface are examined in detail and found to be in general good agreement with those calculated directly from the raw ab initio energies, as well as previous calculations available in the literature. The novel function has been built so as to become degenerate at linear geometries with the ground-state potential energy surface of A'' symmetry reported by our group, where both form a Renner-Teller pair.

Effect of the Mn oxidation state and lattice oxygen in Mn-based TiO2 catalysts on the low-temperature selective catalytic reduction of NO by NH3.

PubMed

Lee, Sang Moon; Park, Kwang Hee; Kim, Sung Su; Kwon, Dong Wook; Hong, Sung Chang

2012-09-01

TiO2-supported manganese oxide catalysts formed using different calcination temperatures were prepared by using the wet-impregnation method and were investigated for their activity in the low-temperature selective catalytic reduction (SCR) of NO by NH3 with respect to the Mn valence and lattice oxygen behavior. The surface and bulk properties of these catalysts were examined using Brunauer-Emmett-Teller (BET) surface area, X-ray diffraction (XRD), temperature-programmed reduction (TPR), and temperature-programmed desorption (TPD). Catalysts prepared using lower calcination temperatures, which contained Mn4+ displayed high SCR activity at low temperatures and possessed several acid sites and active oxygen. The TPD analysis determined that the Brönsted and Lewis acid sites in the Mn/TiO2 catalysts were important for the low-temperature SCR at 80-160 and 200-350 degrees C, respectively. In addition, the available lattice oxygen was important for attaining high NO to NO2 oxidation at low temperatures. Recently, various Mn catalysts have been evaluated as SCR catalysts. However, there have been no studies on the relationship of adsorption and desorption properties and behavior of lattice oxygen according to the valence state for manganese oxides (MnO(x)). Therefore, in this study, the catalysts were prepared by the wet-impregnation method at different calcination temperatures in order to show the difference of manganese oxidation state. These catalysts were then characterized using various physicochemical techniques, including BET, XRD, TPR, and TPD, to understand the structure, oxidation state, redox properties, and adsorption and desorption properties of the Mn/TiO2 catalysts.

Evolutionary Excesses: A Response to Moore

ERIC Educational Resources Information Center

Barr, Stephen M.

2002-01-01

The physicist Edward Teller once gave an interview to a woman from a popular science magazine. He began the interview by saying, "You have heard many bad things about the Hydrogen Bomb. Now I am going to tell you some nice things about it." In reflecting upon a response to Dr. Randy Moore, the author thought of Teller, seeing his role here in…

Alpher, Ralph Asher (1921-)

NASA Astrophysics Data System (ADS)

Murdin, P.

2000-11-01

Physicist, born in Washington, DC. With HANS BETHE and GEORGE GAMOW, he proposed in 1948 the `alpha-beta-gamma' theory of the creation of the elements by successive addition of nucleons to hydrogen to build up the periodic table (the alpha part of the name of the theory referred to Alpher). This idea, subsequently shown by MARGARET BURBIDGE, Geoffery Burbidge, WILLIAM FOWLER and FRED HOYLE to be...

Theoretical study of the potential energy surfaces and dynamics of CaNC/CaCN

NASA Astrophysics Data System (ADS)

Nanbu, Shinkoh; Minamino, Satoshi; Aoyagi, Mutsumi

1997-05-01

Potential energy surfaces for the ground and two low-lying electronically excited states of CaNC/CaCN, are calculated using the ab initio molecular orbital (MO) configuration interaction (CI) method. The absorption and emission spectra of the system are computed by performing time-dependent quantum dynamical calculations on these surfaces. The most stable geometries for the two lowest lying 12Σ+ and 12Π electronic states correspond to the calcium isocyanide (CaNC) structure. These two states are characterized by ionic bonding and the potential energy curves along the bending coordinate are relatively isotropic. The result of our wave packet dynamics shows that the characteristics of the experimental spectra observed by the laser-induced fluorescence spectroscopy can be explained by the Renner-Teller splitting.

Synchrotron radiation-based 61Ni Mössbauer spectroscopic study of Li(Ni1/3Mn1/3Co1/3)O2 cathode materials of lithium ion rechargeable battery

NASA Astrophysics Data System (ADS)

Segi, Takashi; Masuda, Ryo; Kobayashi, Yasuhiro; Tsubota, Takayuki; Yoda, Yoshitaka; Seto, Makoto

2016-12-01

Layered rocksalt type oxides, such as Li(Ni1/3Mn1/3Co1/3)O2, are widely used as the cathode active materials of lithium-ion rechargeable batteries. Because the nickel ions are associated with the role of the charge compensation at discharge and charge, the 61Ni Mössbauer measurements at 6 K using synchrotron radiation were performed to reveal the role of Ni. The Ni ions of the active materials play two roles for the redox process between the charge and discharge states of lithium-ion batteries. Half of the total Ni ions change to the low-spin Ni3+ with Jahn-Teller distortion from the Ni2+ ions of the discharge state. The remainder exhibit low-spin state divalent Ni ions.

The Davida Teller Award Lecture, 2016

PubMed Central

Atkinson, Janette

2017-01-01

Research in the Visual Development Unit on “dorsal stream vulnerability' (DSV) arose from research in two somewhat different areas. In the first, using cortical milestones for local and global processing from our neurobiological model, we identified cerebral visual impairment in infants in the first year of life. In the second, using photo/videorefraction in population refractive screening programs, we showed that infant spectacle wear could reduce the incidence of strabismus and amblyopia, but many preschool children, who had been significantly hyperopic earlier, showed visuo-motor and attentional deficits. This led us to compare developing dorsal and ventral streams, using sensitivity to global motion and form as signatures, finding deficits in motion sensitivity relative to form in children with Williams syndrome, or perinatal brain injury in hemiplegia or preterm birth. Later research showed that this “DSV” was common across many disorders, both genetic and acquired, from autism to amblyopia. Here, we extend DSV to be a cluster of problems, common to many disorders, including poor motion sensitivity, visuo-motor spatial integration for planning actions, attention, and number skills. In current research, we find that individual differences in motion coherence sensitivity in typically developing children are correlated with MRI measures of area variations in parietal lobe, fractional anisotropy (from TBSS) of the superior longitudinal fasciculus, and performance on tasks of mathematics and visuo-motor integration. These findings suggest that individual differences in motion sensitivity reflect decision making and attentional control rather than integration in MT/V5 or V3A. Its neural underpinnings may be related to Duncan's “multiple-demand” (MD) system. PMID:28362900

Controlling the orbital sequence in individual Cu-phthalocyanine molecules.

PubMed

Uhlmann, C; Swart, I; Repp, J

2013-02-13

We report on the controlled change of the energetic ordering of molecular orbitals. Negatively charged copper(II)phthalocyanine on NaCl/Cu(100) undergoes a Jahn-Teller distortion that lifts the degeneracy of two frontier orbitals. The energetic order of the levels can be controlled by Au and Ag atoms in the vicinity of the molecule. As only one of the states is occupied, the control of the energetic order is accompanied by bistable changes of the charge distribution inside the molecule, rendering it a bistable switch.

Validation of vibration-dissociation coupling models in hypersonic non-equilibrium separated flows

NASA Astrophysics Data System (ADS)

Shoev, G.; Oblapenko, G.; Kunova, O.; Mekhonoshina, M.; Kustova, E.

2018-03-01

The validation of recently developed models of vibration-dissociation coupling is discussed in application to numerical solutions of the Navier-Stokes equations in a two-temperature approximation for a binary N2/N flow. Vibrational-translational relaxation rates are computed using the Landau-Teller formula generalized for strongly non-equilibrium flows obtained in the framework of the Chapman-Enskog method. Dissociation rates are calculated using the modified Treanor-Marrone model taking into account the dependence of the model parameter on the vibrational state. The solutions are compared to those obtained using traditional Landau-Teller and Treanor-Marrone models, and it is shown that for high-enthalpy flows, the traditional and recently developed models can give significantly different results. The computed heat flux and pressure on the surface of a double cone are in a good agreement with experimental data available in the literature on low-enthalpy flow with strong thermal non-equilibrium. The computed heat flux on a double wedge qualitatively agrees with available data for high-enthalpy non-equilibrium flows. Different contributions to the heat flux calculated using rigorous kinetic theory methods are evaluated. Quantitative discrepancy of numerical and experimental data is discussed.

Structural evolution of the methane cation in subfemtosecond photodynamics

NASA Astrophysics Data System (ADS)

Mondal, T.; Varandas, A. J. C.

2015-07-01

An ab initio quantum dynamics study has been performed to explore the structural rearrangement of ground state CH 4+ in subfemtosecond resolved photodynamics. The method utilizes time-dependent wave-packet propagation on the X ˜ 2 T 2 electronic manifold of the title cation in full dimensionality, including nonadiabatic coupling of the three electronic sheets. Good agreement is obtained with recent experiments [Baker et al., Science 312, 424 (2006)] which use high-order harmonic generation to probe the attosecond proton dynamics. The novel results provide direct theoretical support of the observations while unravelling the underlying details. With the geometrical changes obtained by calculating the expectation values of the nuclear coordinates as a function of time, the structural evolution is predicted to begin through activation of the totally symmetric a1 and doubly degenerate e modes. While the former retains the original Td symmetry of the cation, the Jahn-Teller active e mode conducts it to a D2d structure. At ˜1.85 fs, the intermediate D2d structure is further predicted to rearrange to local C2v minimum geometry via Jahn-Teller active bending vibrations of t2 symmetry.

Multiconfiguration Self-Consistent Field Study on Formonitrile Imine and N-Substituted Nitrile Imines HCN2-R: Energy Component Analysis of the Pseudo-Jahn-Teller Effect.

PubMed

Toyota, Azumao; Muramatsu, Takashi; Koseki, Shiro

2017-03-23

Stable geometrical structures for formonitrile imine (1) and N-substituted nitrile imines HCN 2 -R (R = Li, BeH, BH 2 , CH 3 , CN, CCH, C 6 H 5 , NH 2 , OH, and F) (2-11) were examined by using the multiconfiguration self-consistent-field (MCSCF) method followed by second-order configuration interaction (SOCI) calculations and second-order multiconfiguration quasi-degenerate perturbation theory (MCQDPT2) calculations, together with the aug-cc-pVTZ basis sets. The results show that 1 suffers a pseudo-Jahn-Teller (JT) distortion from a linear C ∞v structure to a C 1 structure via a planar bent C s structure. Each of the others is found to undergo pseudo-JT distortion from a symmetrical structure to a planar bent C s structure for 2, 3, and 7 and to a C 1 structure for 4, 5, 6, 8, 9, 10, and 11. At the stationary structures of 1-11, the structural characteristics were briefly discussed in terms of allenic and propargylic. To elucidate the nature of pseudo-JT distortions, energy component analyses were carried out at the MCSCF+SOCI level of theory at all of the stationary structures for the relevant molecules. In most of the molecules examined, pseudo-JT stabilizations were classified into two groups, one in which the stability arises from a lowering of the energy of the attractive term V en and the other in which the stability results from a lowering of the energy of the repulsive terms V nn and V ee . In addition to the above two groups, it was also found that the following three groups are responsible for the pseudo-JT stabilizations in a certain stage of the structural changes. Namely, one is a lowering of the energy of the term V ee observed in 6, another is a lowering of the energy of the terms V ee and V en observed in 9-11, and the other is a lowering of the energy of the terms V en and V nn observed in 10. These energetic behaviors were accounted in terms of an elongation or a contraction of the molecular skeleton, a migration of electrons from one part of

Registered report: measuring unconscious deception detection by skin temperature

PubMed Central

van ’ t Veer, Anna E.; Stel, Mariëlle; van Beest, Ilja; Gallucci, Marcello

2014-01-01

Findings from the deception detection literature suggest that although people are not skilled in consciously detecting a liar, they may intuit that something about the person telling a lie is off. In the current proposal, we argue that observing a liar influences the observer’s physiology even though the observer may not be consciously aware of being lied to (i.e., the observers’ direct deception judgment does not accurately differentiate between liars and truth-tellers). To test this hypothesis, participants’ finger temperature will be measured while they watch videos of persons who are either honest or dishonest about their identity. We hypothesize that skin temperature will be lower when observing a liar than when observing a truth-teller. Additionally, we test whether perceiving a liar influences finger skin temperature differently when an individual is, or is not, alerted to the possibility of deceit. We do this by varying participants’ awareness of the fact that they might be lied to. Next to measuring physiological responses to liars and truth-tellers, self-reported direct and indirect veracity judgments (i.e., trustworthiness and liking) of the target persons will be assessed. We hypothesize that indirect veracity judgments will better distinguish between liars and truth-tellers than direct veracity judgments. PMID:24904461

Insurance based lie detection: Enhancing the verifiability approach with a model statement component.

PubMed

Harvey, Adam C; Vrij, Aldert; Leal, Sharon; Lafferty, Marcus; Nahari, Galit

2017-03-01

The Verifiability Approach (VA) is verbal lie detection tool that has shown promise when applied to insurance claims settings. This study examined the effectiveness of incorporating a Model Statement comprised of checkable information to the VA protocol for enhancing the verbal differences between liars and truth tellers. The study experimentally manipulated supplementing (or withholding) the VA with a Model Statement. It was hypothesised that such a manipulation would (i) encourage truth tellers to provide more verifiable details than liars and (ii) encourage liars to report more unverifiable details than truth tellers (compared to the no model statement control). As a result, it was hypothesized that (iii) the model statement would improve classificatory accuracy of the VA. Participants reported 40 genuine and 40 fabricated insurance claim statements, in which half the liars and truth tellers where provided with a model statement as part of the VA procedure, and half where provide no model statement. All three hypotheses were supported. In terms of accuracy, the model statement increased classificatory rates by the VA considerably from 65.0% to 90.0%. Providing interviewee's with a model statement prime consisting of checkable detail appears to be a useful refinement to the VA procedure. Copyright © 2017 Elsevier B.V. All rights reserved.

Astrophysical Impact of the Updated 9Be(p,α)6Li and 10B(p,α)7Be Reaction Rates As Deduced By THM

NASA Astrophysics Data System (ADS)

Lamia, L.; Spitaleri, C.; Tognelli, E.; Degl'Innocenti, S.; Pizzone, R. G.; Prada Moroni, P. G.

2015-10-01

The complete understanding of the stellar abundances of lithium, beryllium, and boron represents one of the most interesting open problems in astrophysics. These elements are largely used to probe stellar structure and mixing phenomena in different astrophysical scenarios, such as pre-main-sequence or main-sequence stars. Their different fragility against (p,α) burning reactions allows one to investigate different depths of the stellar interior. Such fusion mechanisms are triggered at temperatures between T ≈ (2-5) × {10}6 K, thus defining a corresponding Gamow energy between ≈ 3-10 keV, where S(E)-factor measurements need to be performed to get reliable reaction rate evaluations. The Trojan Horse Method is a well defined procedure to measure cross sections at Gamow energies overcoming the uncertainties due to low-energy S(E)-factor extrapolation as well as electron screening effects. Taking advantage of the {\\mathtt{THM}} measure of the 9Be(p,α)6Li and 10B(p,α)7Be cross sections, the corresponding reaction rates have been calculated and compared with the evaluations by the NACRE collaboration, widely used in the literature. The impact on surface abundances of the updated 9Be and 10B (p,α) burning rates is discussed for pre-MS stars.

Response functions for dimers and square-symmetric molecules in four-wave-mixing experiments with polarized light

NASA Astrophysics Data System (ADS)

Smith, Eric Ryan; Farrow, Darcie A.; Jonas, David M.

2005-07-01

Four-wave-mixing nonlinear-response functions are given for intermolecular and intramolecular vibrations of a perpendicular dimer and intramolecular vibrations of a square-symmetric molecule containing a doubly degenerate state. A two-dimensional particle-in-a-box model is used to approximate the electronic wave functions and obtain harmonic potentials for nuclear motion. Vibronic interactions due to symmetry-lowering distortions along Jahn-Teller active normal modes are discussed. Electronic dephasing due to nuclear motion along both symmetric and asymmetric normal modes is included in these response functions, but population transfer between states is not. As an illustration, these response functions are used to predict the pump-probe polarization anisotropy in the limit of impulsive excitation.

Proton-Decay Spectroscopic Studies of the Exotic Nuclides 23Al, 23Si, 22Al and 77Rb

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rowe, Michael William

Aluminum-23 was produced by 40 MeV 3He 2+ bombardments of Mg targets in four experiments at the LBNL 88” Cyclotron. Reaction products were transported via helium-jet to a detection chamber where they were counted using two low-energy particle -identif ication (PI) telescopes. New proton groups were observed with laboratory energies (and intensities relative to the known peak at 838±5 keV) of 246±20 (33±3%) and 556±5 keV (68±5%), respectively. Several possible decay assignments are discussed for the former group. The possibility that it originates from the decay through the isobaric analog state (IAS) and corresponding implications for isospin mixing and themore » proton-capture resonance strength are discussed. The Gamow-TelIer strength function has been deduced from these and several weaker proton transitions; the results are compared with theoretical predictions.« less

A tight binding model study of tunneling conductance spectra of spin and orbitally ordered CMR manganites

NASA Astrophysics Data System (ADS)

Panda, Saswati; Sahoo, D. D.; Rout, G. C.

2018-04-01

We report here a tight binding model for colossal magnetoresistive (CMR) manganites to study the pseudo gap (PG) behavior near Fermi level. In the Kubo-Ohata type DE model, we consider first and second nearest neighbor interactions for transverse spin fluctuations in core band and hopping integrals in conduction band, in the presence of static band Jahn-Teller distortion. The model Hamiltonian is solved using Zubarev's Green's function technique. The electron density of states (DOS) is found out from the Green's functions. We observe clear PG near Fermi level in the electron DOS.

Novel effect of spin dynamics with suppression of charge and orbital ordering in Nd0.5Ca0.5MnO3 under the influence of ac electric field

NASA Astrophysics Data System (ADS)

Sarwar, T.; Qamar, A.; Nadeem, M.

2017-07-01

Dynamics of spin ordering in the manganite Nd0.5Ca0.5MnO3 have been investigated in this paper. It was observed that the complex mixed magnetic ordering in pellets is comprised of antiferromagnetic ordering at 160 K (TN) and complete charge ordering at 250 K (TCO). Under ac field, appearance of unstable ferromagnetic correlations is observed above TCO, which is badly frustrated due to strong spin disorder induced by Jahn Teller distortions. Impedance measurements reveal the spin glass like scenario, suppressing the strong antiferromagnetic and charge ordering states below TN.

Non-polynomial extensions of solvable potentials à la Abraham-Moses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Odake, Satoru; Sasaki, Ryu; Center for Theoretical Sciences, National Taiwan University, Taipei 10617, Taiwan

2013-10-15

Abraham-Moses transformations, besides Darboux transformations, are well-known procedures to generate extensions of solvable potentials in one-dimensional quantum mechanics. Here we present the explicit forms of infinitely many seed solutions for adding eigenstates at arbitrary real energy through the Abraham-Moses transformations for typical solvable potentials, e.g., the radial oscillator, the Darboux-Pöschl-Teller, and some others. These seed solutions are simple generalisations of the virtual state wavefunctions, which are obtained from the eigenfunctions by discrete symmetries of the potentials. The virtual state wavefunctions have been an essential ingredient for constructing multi-indexed Laguerre and Jacobi polynomials through multiple Darboux-Crum transformations. In contrast to themore » Darboux transformations, the virtual state wavefunctions generate non-polynomial extensions of solvable potentials through the Abraham-Moses transformations.« less

Thermal imaging as a lie detection tool at airports.

PubMed

Warmelink, Lara; Vrij, Aldert; Mann, Samantha; Leal, Sharon; Forrester, Dave; Fisher, Ronald P

2011-02-01

We tested the accuracy of thermal imaging as a lie detection tool in airport screening. Fifty-one passengers in an international airport departure hall told the truth or lied about their forthcoming trip in an interview. Their skin temperature was recorded via a thermal imaging camera. Liars' skin temperature rose significantly during the interview, whereas truth tellers' skin temperature remained constant. On the basis of these different patterns, 64% of truth tellers and 69% of liars were classified correctly. The interviewers made veracity judgements independently from the thermal recordings. The interviewers outperformed the thermal recordings and classified 72% of truth tellers and 77% of liars correctly. Accuracy rates based on the combination of thermal imaging scores and interviewers' judgements were the same as accuracy rates based on interviewers' judgements alone. Implications of the findings for the suitability of thermal imaging as a lie detection tool in airports are discussed.

Science and technology review, July-August 1998 issue

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smart, J

On the occasion of Edward Teller's 90th birthday, S&TR has the pleasure of honoring Lawrence Livermore's co-founder and most influential scientist. Teller is known for his inventive work in physics, his concepts leading to thermonuclear explosions, and his strong stands on such issues as science education, the nation's strategic defense, the needs for science in the future, and sharing scientific information. The articles in this issue also show him, as always, tirelessly moving forward with his new and changing interests.

The fiftieth anniversary of the first public announcement of the successful test of fission: Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report contains comments and discussions on the history of fission. The following people comments and lectures are discussed in this report: Remarks and introduction of Maxine F. Singer; president's message, Maxine F. Singer; introduction of Stephen Joel Trachtenberg; President's message, Stephen Joel Trachtenberg; introduction of Frederick Seitz; lecture: Nuclear Science: Promises and Perceptions, '' Frederick Seitz; introduction of K. Alex Mueller; lecture: High Temperature Ferroelectricity and Superconductivity,'' introduction of Edward Teller; and lecture: Toward a More Secure World,'' Edward Teller.

The fiftieth anniversary of the first public announcement of the successful test of fission: Proceedings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This report contains comments and discussions on the history of fission. The following people comments and lectures are discussed in this report: Remarks and introduction of Maxine F. Singer; president`s message, Maxine F. Singer; introduction of Stephen Joel Trachtenberg; President`s message, Stephen Joel Trachtenberg; introduction of Frederick Seitz; lecture: ``Nuclear Science: Promises and Perceptions, `` Frederick Seitz; introduction of K. Alex Mueller; lecture: ``High Temperature Ferroelectricity and Superconductivity,`` introduction of Edward Teller; and lecture: ``Toward a More Secure World,`` Edward Teller.

EPR/ENDOR and Theoretical Study of the Jahn-Teller-Active [HIPTN3N]MoVL Complexes (L = N-, NH).

PubMed

Sharma, Ajay; Roemelt, Michael; Reithofer, Michael; Schrock, Richard R; Hoffman, Brian M; Neese, Frank

2017-06-19

The molybdenum trisamidoamine (TAA) complex [Mo] {[3,5-(2,4,6-i-Pr 3 C 6 H 2 ) 2 C 6 H 3 NCH 2 CH 2 N]Mo} carries out catalytic reduction of N 2 to ammonia (NH 3 ) by protons and electrons at room temperature. A key intermediate in the proposed [Mo] nitrogen reduction cycle is nitridomolybdenum(VI), [Mo(VI)]N. The addition of [e - /H + ] to [Mo(VI)]N to generate [Mo(V)]NH might, in principle, follow one of three possible pathways: direct proton-coupled electron transfer; H + first and then e - ; e - and then H + . In this study, the paramagnetic Mo(V) intermediate {[Mo]N} - and the [Mo]NH transfer product were generated by irradiating the diamagnetic [Mo]N and {[Mo]NH} + Mo(VI) complexes, respectively, with γ-rays at 77 K, and their electronic and geometric structures were characterized by electron paramagnetic resonance and electron nuclear double resonance spectroscopies, combined with quantum-chemical computations. In combination with previous X-ray studies, this creates the rare situation in which each one of the four possible states of [e - /H + ] delivery has been characterized. Because of the degeneracy of the electronic ground states of both {[Mo(V)]N} - and [Mo(V)]NH, only multireference-based methods such as the complete active-space self-consistent field (CASSCF) and related methods provide a qualitatively correct description of the electronic ground state and vibronic coupling. The molecular g values of {[Mo]N} - and [Mo]NH exhibit large deviations from the free-electron value g e . Their actual values reflect the relative strengths of vibronic and spin-orbit coupling. In the course of the computational treatment, the utility and limitations of a formal two-state model that describes this competition between couplings are illustrated, and the implications of our results for the chemical reactivity of these states are discussed.

Partial restoration of spin-isospin SU(4) symmetry and the one-quasiparticle random-phase approximation method in double-β decay

NASA Astrophysics Data System (ADS)

Ferreira, V. dos S.; Krmpotić, F.; Barbero, C. A.; Samana, A. R.

2017-10-01

The one-quasiparticle random-phase approximation (one-QRPA) method is used to describe simultaneously both double-β -decay modes, giving special attention to the partial restoration of spin-isospin SU(4 ) symmetry. To implement this restoration and to fix the model parameters, we resort to the energetics of Gamow-Teller resonances and to the minima of the single-β+-decay strengths. This makes the theory predictive regarding the β β2 ν decay, producing the 2 ν moments in 48Ca, 76Ge, 82Se, 96Zr, 100Mo, Te,130128, and 150Nd, that are of the same order of magnitude as the experimental ones; however, the agreement with β β2 ν data is only modest. To include contributions coming from induced nuclear weak currents, we extend the β β0 ν -decay formalism employed previously in C. Barbero et al., Nucl. Phys. A 628, 170 (1998), 10.1016/S0375-9474(97)00614-3, which is based on the Fourier-Bessel expansion. The numerical results for the β β0 ν moments in the above mentioned nuclei are similar to those obtained in other theoretical studies although smaller on average by ˜40 % . We attribute this difference basically to the one-QRPA method, employed here for the first time, instead of the currently used two-QRPA method. The difference is partially due also to the way of carrying out the restoration of the spin-isospin symmetry. It is hard to say which is the best way to make this restoration, since the β β0 ν moments are not experimentally measurable. The recipe proposed here is based on physically robust arguments. The numerical uncertainties in the β β moments, related to (i) their strong dependence on the residual interaction in the particle-particle channel when evaluated within the QRPA, and (ii) lack of proper knowledge of single-particle energies, have been quantified. It is concluded that the partial restoration of the SU(4 ) symmetry, generated by the residual interaction, is crucial in the description of the β β decays, regardless of the nuclear

Magnetic properties of the Fe{sup II} spin crossover complex in emulsion polymerization of trifluoroethylmethacrylate using poly(vinyl alcohol)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Suzuki, Atsushi, E-mail: suzuki@mat.usp.ac.j; Iguchi, Motoi; Oku, Takeo

2010-04-15

Influence of chemical substitution in the Fe{sup II} spin crossover complex on magnetic properties in emulsion polymerization of trifluoroethylmethacrylate using poly(vinyl alcohol) as a protective colloid was investigated near its high spin/low spin (HS/LS) phase transition. The obvious bi-stability of the HS/LS phase transition was considered by the identification of multiple spin states between the quintet (S=2) states to single state (S=0) across the excited triplet state (S=1). Magnetic parameters of gradual shifts of anisotropy g-tensor supported by the molecular distortion of the spin crossover complex would arise from a Jahn-Teller effect regarding ligand field theory on the basis ofmore » a B3LYP density functional theory using electron spin resonance (ESR) spectrum and X-ray powder diffraction. - Graphical abstract: AFM surface image of the emulsion particles with the spin crossover complex.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krasnenko, V.; Boltrushko, V.; Hizhnyakov, V.

Chemically bound states of benzene molecules with graphene are studied both analytically and numerically. The states are formed by switching off intrabonds of π-electrons in C{sub 6} rings to interbonds. A number of different undistorted and distorted structures are established both with aligned and with transversal mutual orientation of benzene and graphene. The vibronic interactions causing distortions of bound states are found, by using a combination of analytical and numerical considerations. This allows one to determine all electronic transitions of π-electrons without explicit numerical calculations of excited states, to find the conical intersections of potentials, and to show that themore » mechanism of distortions is the pseudo-Jahn-Teller effect. It is found that the aligned distorted benzene molecule placed between two graphene sheets makes a chemical bond with both of them, which may be used for fastening of graphene sheets together.« less

Structure and Stability of Carboxylate Complexes. 20. Diaqua Bis(methoxyacetato) Complexes of Nickel(II), Copper(II), and Zinc(II): A Structural Study of the Dynamic Pseudo-Jahn-Teller Effect.

PubMed

Prout, Keith; Edwards, Alison; Mtetwa, Victor; Murray, Jon; Saunders, John F.; Rossotti, Francis J. C.

1997-06-18

The crystal structure of trans-diaquabis(methoxyacetato)copper(II), C(6)H(14)O(8)Cu, has been determined by neutron diffraction at 4.2 K (monoclinic, P2(1)/n, a = 6.88(1), b = 7.19(1), c = 9.77(2) Å, gamma = 95.7(1) degrees, (Z = 2)) and by X-ray diffraction at 125, 165, 205, 240, 265, 295, and 325 K. These measurements show that there is no phase change in the temperature range 4.2-325 K. The copper(II) coordination at 4.2 K is a tetragonally distorted elongated rhombic octahedron (Cu-OOC 1.955(1), Cu-OMe 2.209(1), and Cu-OH(2) 2.031(2) Å). As the temperature increases to 325 K, the Cu-OOC bonds shorten slightly to 1.934(5) Å, the Cu-OMe bonds shorten more markedly to 2.137(4) Å, and Cu-OH(2) lengthens to 2.155(6) Å to give a tetragonally distorted compressed rhombic octahedron. For comparison the structure of the isomorphous nickel(II) complex (monoclinic, P2(1)/n, a = 6.633(1), b = 7.192(1), c = 10.016(2) Å, gamma = 98.30(2) degrees, (Z = 2)) has been redetermined at 295 K and the structure of the analogous zinc(II) complex (orthorhombic, F2dd, a = 7.530(1), b = 13.212(1), c = 21.876(2) Å (Z = 8)) has also been determined. The nickel(II) complex has an almost regular trans (centrosymmetric) octahedral coordination (Ni-OOC 2.022(1), Ni-OMe 2.043(1), and Ni-OH(2) 2.077(2) Å). However, zinc(II) has a very distorted octahedral coordination with the zinc atom on a 2-fold axis with the water molecules and the methoxy ligators cis and the carboxylate ligators trans (Zn-OOC 1.985(1), Zn-OMe 2.304(2), and Zn-OH(2) 2.038(2) Å). The variation in the dimensions of the copper(II) coordination sphere is discussed in terms of static (low temperature) and planar dynamic (high temperature) pseudo-Jahn-Teller effects.

Some remarks concerning the centrifugal term approximation

NASA Astrophysics Data System (ADS)

Ferreira, F. J. S.; Bezerra, V. B.

2017-10-01

We generalize the Pekeris approximation for the centrifugal term potential, l/(l +1 ) r2 , and use this to obtain the solutions of the radial Schrödinger equation for the arbitrary angular quantum number, l, of the Hulthén potential. We also obtain the expressions for the bound state energies corresponding to this potential and calculate their values for different states and compare with other results presented in the literature. We also consider some models of physical potentials, namely, the Eckart potential, the Poschl-Teller potentials, the Rosen-Morse potential, the Woods-Saxon potential, and the Manning-Rosen potential. Thus, following straightforward the example corresponding to the Hulthén potential, we show what the radial solutions and the energy spectra for these potentials are.

Orbital effects in cobaltites by neutron scattering

NASA Astrophysics Data System (ADS)

Louca, Despina

2005-03-01

The orbital degree of freedom can play a central role in the physics of transition metal perovskite oxides because of its intricate coupling with other degrees of freedom such as spin, charge and lattice. In this talk the case of La1-xSrxCoO3 will be presented. Using elastic and inelastic neutron scattering, we investigated the thermal evolution of the local atomic structure and lattice dynamics in the pure sample and with the addition of charge carriers as the system crosses over from a paramagnetic insulator to a ferromagnetic metal. In LaCoO3, the thermal activation of the Co ions from a nonmagnetic ground state to an intermediate spin state gives rise to orbital degeneracy. This leads to Jahn-Teller distortions that are dynamical in nature. Doping stabilizes the intermediate spin configuration of the Co ions in the paramagnetic insulating phase. Evidence for local static Jahn-Teller distortions is observed but without long-range ordering. The size of the JT lattice is proportional to the amount of charge. However, with cooling to the metallic phase, static JT distortions disappear for x <= 30 %, the percolation limit. This coincides with narrowing of two modes at φ=22,nd,4,eV in the phonon spectrum in which we argue is due to localized dynamical JT fluctuations^1. The implications of the orbital effects to the structural and magnetic properties will be discussed. ^1D. Louca and J. L. Sarrao, Phys. Rev. Lett. 91, 155501 (2003).

Isovector excitations in 100Nb and their decays by neutron emission studied via the Mo 100 ( t , He 3 + n ) reaction at 115 MeV/u

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miki, K.; Zegers, R. G. T.; Austin, Sam M.

Here, spin–isospin excitations in 100Nb were studied via the charge-exchange reaction at 115 MeV/u with the goal to constrain theoretical models used to describe the isovector spin response of nuclei. The experiment was performed with a secondary beam of tritons, and 3He particles were analyzed in the S800 magnetic spectrometer. Decay by neutron emission from excited states in 100Nb was observed by using plastic and liquid scintillator arrays. Differential cross sections were analyzed and monopole excitations were revealed by using a multipole decomposition analysis. The Gamow–Teller transition strength observed at low excitation energies, which is important for estimating the electron-capturemore » rate in astrophysical scenarios, was strongly fragmented and reduced compared to single-particle and spherical mean-field models. The consideration of deformation in the theoretical estimates was found to be important to better describe the fragmentation and strengths. A strong excitation of the isovector spin giant monopole resonance was observed, and well reproduced by the mean-field models. Its presence makes the extraction of Gamow–Teller strengths at high excitation energies difficult. The branches for statistical and direct decay by neutron emission were identified in the spectra. The upper limit for the branching ratio by direct decay (integrated over all observed excitations) was determined to be 20 ± 6%. Even though the statistical uncertainties in the neutron-coincident data were too large to perform detailed studies of the decay by neutron emission from individual states and resonances, the experiment demonstrates the feasibility of the method.« less

Isovector excitations in 100Nb and their decays by neutron emission studied via the Mo 100 ( t , He 3 + n ) reaction at 115 MeV/u

DOE PAGES

Miki, K.; Zegers, R. G. T.; Austin, Sam M.; ...

2017-04-07

Here, spin–isospin excitations in 100Nb were studied via the charge-exchange reaction at 115 MeV/u with the goal to constrain theoretical models used to describe the isovector spin response of nuclei. The experiment was performed with a secondary beam of tritons, and 3He particles were analyzed in the S800 magnetic spectrometer. Decay by neutron emission from excited states in 100Nb was observed by using plastic and liquid scintillator arrays. Differential cross sections were analyzed and monopole excitations were revealed by using a multipole decomposition analysis. The Gamow–Teller transition strength observed at low excitation energies, which is important for estimating the electron-capturemore » rate in astrophysical scenarios, was strongly fragmented and reduced compared to single-particle and spherical mean-field models. The consideration of deformation in the theoretical estimates was found to be important to better describe the fragmentation and strengths. A strong excitation of the isovector spin giant monopole resonance was observed, and well reproduced by the mean-field models. Its presence makes the extraction of Gamow–Teller strengths at high excitation energies difficult. The branches for statistical and direct decay by neutron emission were identified in the spectra. The upper limit for the branching ratio by direct decay (integrated over all observed excitations) was determined to be 20 ± 6%. Even though the statistical uncertainties in the neutron-coincident data were too large to perform detailed studies of the decay by neutron emission from individual states and resonances, the experiment demonstrates the feasibility of the method.« less

A Gaussian Wave Packet Propagation Approach to Vibrationally Resolved Optical Spectra at Non-Zero Temperatures.

PubMed

Reddy, Ch Sridhar; Prasad, M Durga

2016-04-28

An effective time dependent approach based on a method that is similar to the Gaussian wave packet propagation (GWP) technique of Heller is developed for the computation of vibrationally resolved electronic spectra at finite temperatures in the harmonic, Franck-Condon/Hertzberg-Teller approximations. Since the vibrational thermal density matrix of the ground electronic surface and the time evolution operator on that surface commute, it is possible to write the spectrum generating correlation function as a trace of the time evolved doorway state. In the stated approximations, the doorway state is a superposition of the harmonic oscillator zero and one quantum eigenfunctions and thus can be propagated by the GWP. The algorithm has an O(N(3)) dependence on the number of vibrational modes. An application to pyrene absorption spectrum at two temperatures is presented as a proof of the concept.

Ferromagnetism in LaCoO3 nanoparticles

NASA Astrophysics Data System (ADS)

Zhou, Shiming; Shi, Lei; Zhao, Jiyin; He, Laifa; Yang, Haipeng; Zhang, Shangming

2007-11-01

We have investigated the structural and magnetic properties of LaCoO3 nanoparticles prepared by a sol-gel method. A ferromagnetic order with TC˜85K has been observed in the nanoparticles. The infrared spectra give evidence for a stabilizing of higher spin state and a reduced Jahn-Teller distortion in the nanoparticles with respect to the bulk LaCoO3 , which is consistent with the recent reports in the strained films [Phys. Rev. B 75, 144402 (2007)] and proposed to be the possible origin of the observed ferromagnetic order in LaCoO3 .

DOE Office of Scientific and Technical Information (OSTI.GOV)

Libby, S B; Weiss, M S

Edward Teller was one of the great physicists of the twentieth century. His career began just after the key ideas of the quantum revolution of the 1920's were completed, opening vast areas of physics and chemistry to detailed understanding. Thus, his early work in theoretical physics focused on applying the new quantum theory to the understanding of diverse phenomena. These topics included chemical physics, diamagnetism, and nuclear physics. Later, he made key contributions to statistical mechanics, surface physics, solid state, and plasma physics. In many cases, the ideas in these papers are still rich with important ramifications.

Ionization potential depression and optical spectra in a Debye plasma model

NASA Astrophysics Data System (ADS)

Lin, Chengliang; Röpke, Gerd; Reinholz, Heidi; Kraeft, Wolf-Dietrich

2017-11-01

We show how optical spectra in dense plasmas are determined by the shift of energy levels as well as the broadening owing to collisions with the plasma particles. In lowest approximation, the interaction with the plasma particles is described by the RPA dielectric function, leading to the Debye shift of the continuum edge. The bound states remain nearly un-shifted, their broadening is calculated in Born approximation. The role of ionization potential depression as well as the Inglis-Teller effect are shown. The model calculations have to be improved going beyond the lowest (RPA) approximation when applying to WDM spectra.

Patients as story-tellers of healthcare journeys.

PubMed

Lamprell, Klay; Braithwaite, Jeffrey

2016-09-01

There are gaps in our comprehension of patients' subjective experiences as they engage with and transit through the healthcare environments implicated in their treatment trajectories. Patients' stories, unlike patient experience data gathered in questionnaires and surveys, express the deeply personal, narrative nature of the journeys that patients take, creating opportunities for qualitative healthcare research. Yet narrative capabilities and propensities vary with individuals, and are affected by the stresses of illness and treatment. This article extends the growing interest in narrative competence training for both practitioners and patients with the investigation of a story-telling model that could facilitate patients to narrate their experiences of healthcare systems. This model is derived from the literary arts. In fiction and autobiography, the journey arc of the central character is often one in which he or she is compelled to leave the comfort of everyday life and face a series of extraordinary events involving challenge and change which forces the character towards practical, intellectual, psychological and philosophical adjustments that define, by the end of the story, the character's 'new normal'. This pattern is known as the 'hero journey'. Its parallels with patients' experiences of healthcare and the way people narrate their stories of illness have long been recognised. We present here a new idea for applying this model as a narrative structure by which patients may construct their stories about being in and moving through the healthcare system. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Mário Schenberg: Physicist, politician and art critic

NASA Astrophysics Data System (ADS)

Guzzo, M. M.; Reggiani, N.

2015-12-01

Mário Schenberg is considered one of the greatest theoretical physicists of Brazil. He worked in different fields of physics including thermodynamics, quantum mechanics, statistical mechanics, general relativity, astrophysics and mathematics. He was assistant of the Ukrainian naturalized Italian physicist Gleb Wataghin and worked with prestigious physicists like as the Brazilians José Leite Lopes and César Lattes, the Russian-born American George Gamow and the Indian astrophysicist Subrahmanyan Chandrasekhar. Besides, he was also an active politician and critic of art.

Mário Schenberg: Physicist, politician and art critic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guzzo, M. M., E-mail: guzzo@ifi.unicamp.br; Reggiani, N.

2015-12-17

Mário Schenberg is considered one of the greatest theoretical physicists of Brazil. He worked in different fields of physics including thermodynamics, quantum mechanics, statistical mechanics, general relativity, astrophysics and mathematics. He was assistant of the Ukrainian naturalized Italian physicist Gleb Wataghin and worked with prestigious physicists like as the Brazilians José Leite Lopes and César Lattes, the Russian-born American George Gamow and the Indian astrophysicist Subrahmanyan Chandrasekhar. Besides, he was also an active politician and critic of art.

Analysis of Rotationally Resolved Spectra to Non-Degenerate (a''_1) Upper-State Vibronic Levels in the tilde{A} ^2E''-tilde{X}^2A^'_2 Electronic Transition of NO_3

NASA Astrophysics Data System (ADS)

Roudjane, Mourad; Codd, Terrance Joseph; Chen, Ming-Wei; Tran, Henry; Melnik, Dmitry G.; Miller, Terry A.; Stanton, John F.

2015-06-01

The vibronic structure of the tilde{A}-tilde{X} electronic spectrum of NO_3 has been observed using both room-temperature and jet-cooled samples. A recent analysis of this structure is consistent with the Jahn-Teller effect (JTE) in the e^' ν_3 vibrational mode (N-O stretch) being quite strong while the JTE in the e^' ν_4 mode (O-N-O) bend) is rather weak. Electronic structure calculations qualitatively predict these results but the calculated magnitude of the JTE is quantitatively inconsistent with the spectral analysis. Rotationally resolved spectra have been obtained for over a dozen vibronic bands of the tilde{A}-tilde{X} electronic transition in NO_3. An analysis of these spectra should provide considerably more experimental information about the JTE in the tilde{A} state of NO_3 as the rotational structure should be quite sensitive to the geometric distortion of the molecule due to the JTE. This talk will focus upon the parallel bands, which terminate on tilde{A} state levels of a''_1 vibronic symmetry, which were the subject of a preliminary analysis reported at this meeting in 2014. We have now recorded the rotational structure of over a half-dozen parallel bands and have completed analysis on the 3^1_0 and 3^1_0 4^1_0 transitions with several other bands being reasonably well understood. Two general conclusions emerge from this work. (i) All the spectral bands show evidence of perturbations which can reasonably be assumed to result from interactions of the observed tilde{A} state levels with high vibrational levels of the tilde{X} state. The perturbations range from severe in some bands to quite modest in others. (ii) Analyses of observed spectra, insofar as the perturbations permit, have all been performed with an oblate symmetric top model including only additional spin-rotation effects. This result is, of course, consistent with an effective, undistorted geometry for NO_3 of D3h symmetry on the rotational timescale.

31Cl beta decay and the 30P31S reaction rate in nova nucleosynthesis

NASA Astrophysics Data System (ADS)

Bennett, Michael; Wrede, C.; Brown, B. A.; Liddick, S. N.; Pérez-Loureiro, D.; NSCL e12028 Collaboration

2016-03-01

The 30P31S reaction rate is critical for modeling the final isotopic abundances of ONe nova nucleosynthesis, identifying the origin of presolar nova grains, and calibrating proposed nova thermometers. Unfortunately, this rate is essentially experimentally unconstrained because the strengths of key 31S proton capture resonances are not known, due to uncertainties in their spins and parities. Using a 31Cl beam produced at the National Superconducting Cyclotron Laboratory, we have populated several 31S states for study via beta decay and devised a new decay scheme which includes updated beta feedings and gamma branchings as well as multiple states previously unobserved in 31Cl beta decay. Results of this study, including the unambiguous identification due to isospin mixing of a new l = 0 , Jπ = 3 /2+ 31S resonance directly in the middle of the Gamow Window, will be presented, and significance to the evaluation of the 30P31S reaction rate will be discussed. Work supported by U.S. Natl. Sci. Foundation (Grants No. PHY-1102511, PHY-1404442, PHY-1419765, and PHY-1431052); U.S. Dept. of Energy, Natl. Nucl. Security Administration (Award No. DE-NA0000979); Nat. Sci. and Eng. Research Council of Canada.

Puzzling Two-Proton Decay of 67Kr

NASA Astrophysics Data System (ADS)

Wang, S. M.; Nazarewicz, W.

2018-05-01

Ground-state two-proton (2 p ) radioactivity is a rare decay mode found in a few very proton-rich isotopes. The 2 p decay lifetime and properties of emitted protons carry invaluable information on nuclear structure in the presence of a low-lying proton continuum. The recently measured 2 p decay of 67Kr turned out to be unexpectedly fast. Since 67Kr is expected to be a deformed system, we investigate the impact of deformation effects on the 2 p radioactivity. We apply the recently developed Gamow coupled-channel framework, which allows for a precise description of three-body systems in the presence of rotational and vibrational couplings. This is the first application of a three-body approach to a two-nucleon decay from a deformed nucleus. We show that deformation couplings significantly increase the 2 p decay width of 67Kr; this finding explains the puzzling experimental data. The calculated angular proton-proton correlations reflect a competition between 1 p and 2 p decay modes in this nucleus.

Absolute cross sections of the 86Sr(α,n)89Zr reaction at energies of astrophysical interest

NASA Astrophysics Data System (ADS)

Oprea, Andreea; Glodariu, Tudor; Filipescu, Dan; Gheorghe, Ioana; Mitu, Andreea; Boromiza, Marian; Bucurescu, Dorel; Costache, Cristian; Cata-Danil, Irina; Florea, Nicoleta; Ghita, Dan Gabriel; Ionescu, Alina; Marginean, Nicolae; Marginean, Raluca; Mihai, Constantin; Mihai, Radu; Negret, Alexandru; Nita, Cristina; Olacel, Adina; Pascu, Sorin; Sotty, Cristophe; Suvaila, Rares; Stan, Lucian; Stroe, Lucian; Serban, Andreea; Stiru, Irina; Toma, Sebastian; Turturica, Andrei; Ujeniuc, Sorin

2017-09-01

Absolute cross sections for the 86Sr(α,n)89Zr reaction at energies close to the Gamow window are reported. Three thin SrF2 targets were irradiated using the 9 MV Tandem facility in IFIN-HH Bucharest that delivered α beams for the activation process. Two high-purity Germanium detectors were used to measure the induced activity of 89Zr in a low background environment. The experimental results are in very good agreement with Hauser-Feshbach statistical model calculations performed with the TALYS code.

First Measurement of the 19F(α, p)22Ne Reaction at Energies of Astrophysical Relevance

NASA Astrophysics Data System (ADS)

Pizzone, R. G.; D'Agata, G.; La Cognata, M.; Indelicato, I.; Spitaleri, C.; Blagus, S.; Cherubini, S.; Figuera, P.; Grassi, L.; Guardo, G. L.; Gulino, M.; Hayakawa, S.; Kshetri, R.; Lamia, L.; Lattuada, M.; Mijatović, T.; Milin, M.; Miljanić D., Đ.; Prepolec, L.; Rapisarda, G. G.; Romano, S.; Sergi, M. L.; Skukan, N.; Soić, N.; Tokić, V.; Tumino, A.; Uroić, M.

2017-02-01

The observational 19F abundance in stellar environments systematically exceeds the predicted one, thus representing one of the unsolved challenges for stellar modeling. It is therefore clear that further investigation is needed in this field. In this work, we focus our attention on the measurement of the {}19{{F}}{(α ,p)}22{Ne} reaction in the astrophysical energy range, between 0.2 and 0.8 MeV (far below the Coulomb barrier, 3.8 MeV), as it represents the main destruction channel in He-rich environments. The lowest energy at which this reaction has been studied with direct measurements is ˜0.66 MeV, covering only the upper tail of the Gamow window, causing the reaction-rate evaluation to be based on extrapolation. To investigate lower energies, the {}19{{F}}{(α ,p)}22{Ne} reaction has been studied by means of the Trojan horse method, applied to the quasi-free {}6{Li}{{(}19{{F}},{p}22{Ne})}2{{H}} reaction at E beam = 6 MeV. The indirect cross section of the {}19{{F}}{(α ,p)}22{Ne} reaction at energies ≲1 MeV was extracted, fully covering the astrophysical region of interest and overlapping existing direct data for normalization. Several resonances have been detected for the first time inside the Gamow window. The reaction rate has been calculated, showing an increase up to a factor of 4 with respect to the literature at astrophysical temperatures. This might lead to potential major astrophysical implications.

Study of the ion kinetic effects in ICF run-away burn using a quasi-1D hybrid model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Cheng -Kun; Molvig, Kim; Albright, Brian James

Here, the loss of fuel ions in the Gamow peak and other kinetic effects related to the α particles during ignition, run-away burn, and disassembly stages of an inertial confinement fusion D-T capsule are investigated with a quasi-1D hybrid volume ignition model that includes kinetic ions, fluid electrons, Planckian radiation photons, and a metallic pusher. The fuel ion loss due to the Knudsen effect at the fuel-pusher interface is accounted for by a local-loss model by with an albedo model for ions returning from the pusher wall. The tail refilling and relaxation of the fuel ion distribution are captured withmore » a nonlinear Fokker-Planck solver. Alpha heating of the fuel ions is modeled kinetically while simple models for finite alpha range and electron heating are used. This dynamical model is benchmarked with a 3 T hydrodynamic burn model employing similar assumptions. For an energetic pusher (~40 kJ) that compresses the fuel to an areal density of ~1.07g/cm 2 at ignition, the simulation shows that the Knudsen effect can substantially limit ion temperature rise in runaway burn. While the final yield decreases modestly from kinetic effects of the α particles, large reduction of the fuel reactivity during ignition and runaway burn may require a higher Knudsen loss rate compared to the rise time of the temperatures above ~25 keV when the broad D-T Gamow peak merges into the bulk Maxwellian distribution.« less

Study of the ion kinetic effects in ICF run-away burn using a quasi-1D hybrid model

DOE PAGES

Huang, Cheng -Kun; Molvig, Kim; Albright, Brian James; ...

2017-02-21

Here, the loss of fuel ions in the Gamow peak and other kinetic effects related to the α particles during ignition, run-away burn, and disassembly stages of an inertial confinement fusion D-T capsule are investigated with a quasi-1D hybrid volume ignition model that includes kinetic ions, fluid electrons, Planckian radiation photons, and a metallic pusher. The fuel ion loss due to the Knudsen effect at the fuel-pusher interface is accounted for by a local-loss model by with an albedo model for ions returning from the pusher wall. The tail refilling and relaxation of the fuel ion distribution are captured withmore » a nonlinear Fokker-Planck solver. Alpha heating of the fuel ions is modeled kinetically while simple models for finite alpha range and electron heating are used. This dynamical model is benchmarked with a 3 T hydrodynamic burn model employing similar assumptions. For an energetic pusher (~40 kJ) that compresses the fuel to an areal density of ~1.07g/cm 2 at ignition, the simulation shows that the Knudsen effect can substantially limit ion temperature rise in runaway burn. While the final yield decreases modestly from kinetic effects of the α particles, large reduction of the fuel reactivity during ignition and runaway burn may require a higher Knudsen loss rate compared to the rise time of the temperatures above ~25 keV when the broad D-T Gamow peak merges into the bulk Maxwellian distribution.« less

Ultrafast Charge Transfer in Nickel Phthalocyanine Probed by Femtosecond Raman-Induced Kerr Effect Spectroscopy

PubMed Central

2015-01-01

The recently developed technique of femtosecond stimulated Raman spectroscopy, and its variant, femtosecond Raman-induced Kerr effect spectroscopy (FRIKES), offer access to ultrafast excited-state dynamics via structurally specific vibrational spectra. We have used FRIKES to study the photoexcitation dynamics of nickel(II) phthalocyanine with eight butoxy substituents, NiPc(OBu)8. NiPc(OBu)8 is reported to have a relatively long-lived ligand-to-metal charge-transfer (LMCT) state, an essential characteristic for efficient electron transfer in photocatalysis. Following photoexcitation, vibrational transitions in the FRIKES spectra, assignable to phthalocyanine ring modes, evolve on the femtosecond to picosecond time scales. Correlation of ring core size with the frequency of the ν10 (asymmetric C–N stretching) mode confirms the identity of the LMCT state, which has a ∼500 ps lifetime, as well as that of a precursor d-d excited state. An even earlier (∼0.2 ps) transient is observed and tentatively assigned to a higher-lying Jahn–Teller-active LMCT state. This study illustrates the power of FRIKES spectroscopy in elucidating ultrafast molecular dynamics. PMID:24841906

Potential energy surface of cyclooctatetraene

NASA Astrophysics Data System (ADS)

Andrés, José L.; Castaño, Obis; Morreale, Antonio; Palmeiro, Raul; Gomperts, Roberto

1998-01-01

We present a theoretical study of the cyclooctatetraene (COT) molecule. Seven COT structures are located on the singlet ground state potential energy surface. Four of them, which present D2d (tub), Cs (bicyclo[4.2.0]octa-2,4,7-triene or BOT), C2h (chair) and D4 (crown) symmetries are stable species, and the other three are transition state structures showing Cs, D4h, and D8h symmetry. We discuss the symmetry of wave functions for these stationary points. Geometries, energies, and harmonic vibrational frequencies of these structures, and energy gaps between singlet-triplet states and low-lying singlets are presented. For the planar D4h and D8h structures, Jahn-Teller and tunneling effects have also been discussed. Ring inversion, bond shifting and valence isomerization reactive channels from the tub COT conformer are discussed from the point of view of the corresponding transition state structures. Where possible, in order to lend support to this theoretical information comparisons with recent transition state spectroscopy data are made.

Y{sub 2}MoSe{sub 3}O{sub 12} and Y{sub 2}MoTe{sub 3}O{sub 12}: Solid-state synthesis, structure determination, and characterization of two new quaternary mixed metal oxides containing asymmetric coordination environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bang, Seong-eun; Pan, Zhi; Kim, Yeong Hun

Two new quaternary yttrium molybdenum selenium/tellurium oxides, Y{sub 2}MoSe{sub 3}O{sub 12} and Y{sub 2}MoTe{sub 3}O{sub 12} have been prepared by standard solid-state reactions using Y{sub 2}O{sub 3}, MoO{sub 3}, and SeO{sub 2} (or TeO{sub 2}) as reagents. Single-crystal X-ray diffraction was used to determine the crystal structures of the reported materials. Although both of the materials contain second-order Jahn–Teller (SOJT) distortive cations and are stoichiometrically similar, they reveal different structural features: while Y{sub 2}MoSe{sub 3}O{sub 12} shows a three-dimensional framework consisting of YO{sub 8}, MoO{sub 6}, and SeO{sub 3} groups, Y{sub 2}MoTe{sub 3}O{sub 12} exhibits a layered structure composed ofmore » YO{sub 8}, MoO{sub 4}, TeO{sub 3}, and TeO{sub 4} polyhedra. With the Mo{sup 6+} cations in Y{sub 2}MoSe{sub 3}O{sub 12}, a C{sub 3}-type intraoctahedral distortion toward a face is observed, in which the direction of the out-of-center distortion for Mo{sup 6+} is away from the oxide ligand linked to a Se{sup 4+} cation. The Se{sup 4+} and Te{sup 4+} cations in both materials are in asymmetric coordination environment attributed to the lone pairs. Elemental analyses, infrared spectroscopy, thermal analyses, intraoctahedral distortions, and dipole moment calculations for the compounds are also presented. - Graphical abstract: Y{sub 2}MoSe{sub 3}O{sub 12} reveals a three-dimensional framework consisting of YO{sub 8}, MoO{sub 6}, and SeO{sub 3} polyhedra, whereas Y{sub 2}MoTe{sub 3}O{sub 12} exhibits a layered structure composed of YO{sub 8}, MoO{sub 4}, TeO{sub 3}, and TeO{sub 4} groups. - Highlights: • Two new selenite and tellurite (Y{sub 2}MoQ{sub 3}O{sub 12}; Q=Se and Te) are synthesized. • Y{sub 2}MoQ{sub 3}O{sub 12} contain second-order Jahn–Teller distortive cations in asymmetric environments. • The intra-octahedral distortion of the Mo{sup 6+} is influenced by the Se{sup 4+}.« less

An Experimental and Quantum Chemical Study of the Electronic Spectrum of the HBCl Free Radical

NASA Astrophysics Data System (ADS)

Gharaibeh, Mohammed A.; Nagarajan, Ramya; Clouthier, Dennis J.; Tarroni, Ricardo

2012-06-01

The chloroborane (HBCl) free radical has a complex electronic spectrum in the visible that involves a transition from a bent ground state to a linear excited state, both of which are the Renner-Teller components of what would be a ^2π state at linearity. We have used the synchronous-scan LIF and single vibronic level emission techniques to untangle the many overlapping vibronic bands and assign upper state K quantum numbers for jet-cooled HBCl and DBCl. The radicals were produced in a pulsed electric discharge jet using a precursor mixture of boron trichloride (BCl_3) and hydrogen or deuterium in high-pressure argon. As an important aid to understanding the data, the ground and excited state high level ab initio potential energy surfaces (PES) have been calculated and the vibrational levels obtained variationally. The calculated ground state levels are in excellent agreement with the emission data validating the quality of the PES. Aside from an approximately 100 cm-1 shift in the upper state electronic term value, the calculated excited state vibrational energy levels and isotope shifts match the LIF data very well, allowing the observed bands to be assigned with confidence.

Single-particle and collective motion in unbound deformed 39Mg

NASA Astrophysics Data System (ADS)

Fossez, K.; Rotureau, J.; Michel, N.; Liu, Quan; Nazarewicz, W.

2016-11-01

Background: Deformed neutron-rich magnesium isotopes constitute a fascinating territory where the interplay between collective rotation and single-particle motion is strongly affected by the neutron continuum. The unbound f p -shell nucleus 39Mg is an ideal candidate to study this interplay. Purpose: In this work, we predict the properties of low-lying resonant states of 39Mg, using a suite of realistic theoretical approaches rooted in the open quantum system framework. Method: To describe the spectrum and decay modes of 39Mg we use the conventional shell model, Gamow shell model, resonating group method, density matrix renormalization group method, and the nonadiabatic particle-plus-rotor model formulated in the Berggren basis. Results: The unbound ground state of 39Mg is predicted to be either a Jπ=7/2 - state or a 3/2 - state. A narrow Jπ=7/2 - ground-state candidate exhibits a resonant structure reminiscent of that of its one-neutron halo neighbor 37Mg, which is dominated by the f7 /2 partial wave at short distances and a p3 /2 component at large distances. A Jπ=3/2 - ground-state candidate is favored by the large deformation of the system. It can be associated with the 1/2 -[321 ] Nilsson orbital dominated by the ℓ =1 wave; hence its predicted width is large. The excited Jπ=1/2 - and 5 /2- states are expected to be broad resonances, while the Jπ=9/2 - and 11/2 - members of the ground-state rotational band are predicted to have very small neutron decay widths. Conclusion: We demonstrate that the subtle interplay between deformation, shell structure, and continuum coupling can result in a variety of excitations in an unbound nucleus just outside the neutron drip line.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sissa, Cristina; Delchiaro, Francesca; Di Maiolo, Francesco

Essential-state models efficiently describe linear and nonlinear spectral properties of different families of charge-transfer chromophores. Here, the essential-state machinery is applied to the calculation of the early-stage dynamics after ultrafast (coherent) excitation of polar and quadrupolar chromophores. The fully non-adiabatic treatment of coupled electronic and vibrational motion allows for a reliable description of the dynamics of these intriguing systems. In particular, the proposed approach is reliable even when the adiabatic and harmonic approximations do not apply, such as for quadrupolar dyes that show a multistable, broken-symmetry excited state. Our approach quite naturally leads to a clear picture for a dynamicalmore » Jahn-Teller effect in these systems. The recovery of symmetry due to dynamical effects is however disrupted in polar solvents where a static symmetry lowering is observed. More generally, thermal disorder in polar solvents is responsible for dephasing phenomena, damping the coherent oscillations with particularly important effects in the case of polar dyes.« less

Impact of hole doping on spin transition in perovskite-type cobalt oxides.

PubMed

Che, Xiangli; Li, Liping; Hu, Wanbiao; Li, Guangshe

2016-06-28

Series of perovskite PrCo1-xNixO3-δ (x = 0-0.4) were prepared and carefully investigated to understand the spin state transition driven by hole doping and further to reveal the effect of spin state transition on electronic conduction. It is shown that with increasing doping level, the transition temperature Ts for Co(3+) ions from low-spin (LS) to intermediate-spin (IS) reduces from 211.9 K for x = 0 to 190.5 K for x = 0.4. XPS and FT-IR spectra demonstrate that hole doping promoted this transition due to a larger Jahn-Teller distortion. Moreover, a thermal activation of spin disorder caused by thermal population of the spin states for Co ions has a great impact on the electrical transport of these perovskite samples. This work may shed light on the comprehension of spin transition in cobalt oxides through hole doping, which is promising for finding new strategies of enhancing electronic conduction, especially for energy and catalysis applications.

Assignment of the photoelectron spectrum of the nitrate anion NO3- and vibronic interactions in the nitrate free radical

NASA Astrophysics Data System (ADS)

Hirota, Eizi

2018-01-01

The unpaired electron orbital of NO3 is of a2‧ symmetry in the ground electronic state, and thus its motion about the symmetry axis of the molecule is free rotation. When a degenerate vibration is excited, however, the free azimuthal rotation of the unpaired electron is perturbed much by nuclear motions of the degenerate mode, as evidenced by high-resolution spectroscopic studies. Thus the ν4 fundamental state, for example, bears some characters of the B ˜ excited electronic state through the Herzberg-Teller (H-T) interaction, and Neumark et al. explained anomalous ν4 progression in the photoelectron spectra of the NO3- anion by the H-T mechanism. However, the interaction parameter Neumark required was too large to reproduce the ν4 molecular parameters in the ground electronic state precisely determined by high-resolution IR spectroscopy. This discrepancy was resolved by the fact that the upper ν4 overtone/combination states of Neumark's photoelectron transitions were primarily of vibrational in nature. The present study thus showed that NO3 bears both vibrational and H-T induced electronic characters in excited states of degenerate modes in the ground electronic state.

Build the co-creative enterprise.

PubMed

Ramaswamy, Venkat; Gouillart, Francis

2010-10-01

These days more companies are inviting customers to help them design products. Now a few are taking things further and including their other stakeholders--employees, suppliers, distributors, and even regulators--in "co-creation" efforts, too. By focusing on improving the experiences of everyone involved, such firms are achieving breakthrough insights, lower costs, new revenues, and new business models. Consider how this worked at France's La Poste, which wanted to expand package delivery and banking services in light of a decline in its mail business. La Poste had three obstacles: unmotivated union tellers, customers disgruntled by long waits, and frustrated local managers, who felt caught in between. The company set some high-level goals and invited all three groups to decide how to reach them together. To get tellers' buy-in, La Poste gave them a say in their schedules. In workshops, the groups figured out when each office should be open and how its space should be configured. a 50% decrease in waiting time, a jump in satisfaction for customers, soaring job satisfaction among tellers, and significant growth in package delivery and banking, despite the recession.

Ab initio study of MF2 (M=Mn, Fe, Co, Ni) rutile-type compounds using the periodic unrestricted Hartree-Fock approach

NASA Astrophysics Data System (ADS)

de P. R. Moreira, Ibério; Dovesi, Roberto; Roetti, Carla; Saunders, Victor R.; Orlando, Roberto

2000-09-01

The ab initio periodic unrestricted Hartree-Fock method has been applied in the investigation of the ground-state structural, electronic, and magnetic properties of the rutile-type compounds MF2 (M=Mn, Fe, Co, and Ni). All electron Gaussian basis sets have been used. The systems turn out to be large band-gap antiferromagnetic insulators; the optimized geometrical parameters are in good agreement with experiment. The calculated most stable electronic state shows an antiferromagnetic order in agreement with that resulting from neutron scattering experiments. The magnetic coupling constants between nearest-neighbor magnetic ions along the [001], [111], and [100] (or [010]) directions have been calculated using several supercells. The resulting ab initio magnetic coupling constants are reasonably satisfactory when compared with available experimental data. The importance of the Jahn-Teller effect in FeF2 and CoF2 is also discussed.

Nonadiabatic nuclear dynamics of the ammonia cation studied by surface hopping classical trajectory calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Belyaev, Andrey K., E-mail: belyaev@herzen.spb.ru; Domcke, Wolfgang, E-mail: wolfgang.domcke@ch.tum.de; Lasser, Caroline, E-mail: classer@ma.tum.de

The Landau–Zener (LZ) type classical-trajectory surface-hopping algorithm is applied to the nonadiabatic nuclear dynamics of the ammonia cation after photoionization of the ground-state neutral molecule to the excited states of the cation. The algorithm employs a recently proposed formula for nonadiabatic LZ transition probabilities derived from the adiabatic potential energy surfaces. The evolution of the populations of the ground state and the two lowest excited adiabatic states is calculated up to 200 fs. The results agree well with quantum simulations available for the first 100 fs based on the same potential energy surfaces. Three different time scales are detected formore » the nuclear dynamics: Ultrafast Jahn–Teller dynamics between the excited states on a 5 fs time scale; fast transitions between the excited state and the ground state within a time scale of 20 fs; and relatively slow partial conversion of a first-excited-state population to the ground state within a time scale of 100 fs. Beyond 100 fs, the adiabatic electronic populations are nearly constant due to a dynamic equilibrium between the three states. The ultrafast nonradiative decay of the excited-state populations provides a qualitative explanation of the experimental evidence that the ammonia cation is nonfluorescent.« less

North Carolina Tales Fly with Fourth Grade Tellers

ERIC Educational Resources Information Center

Westman, Gretchen Daub

2008-01-01

In fourth grade, North Carolina students are required to write their own personal narratives. The teachers felt that telling a story would be a great stepping stone toward writing one. Rather than focusing on grammar and the mechanics of writing, students could focus on story development and creativity. In this article, the author describes how…

Histories and Horoscopes: The Ethnographer as Fortune-Teller.

ERIC Educational Resources Information Center

Hamilton, Mary

1998-01-01

Focuses on different ways participants in a research project may understand the research and use it themselves by describing how 20 adult students and 14 community members, participants in a recent ethnographic study of adult literacy in England, responded to the invitation to collaborate with researchers in interpreting interview data. (SLD)

12 CFR 704.12 - Permissible services.

Code of Federal Regulations, 2011 CFR

2011-01-01

... teller machines, online transaction processing through a website, website hosting services, account... liquidity planning and balance sheet modeling and analysis. (6) Operational services. Operational services...

Description of proton radioactivity using the Coulomb and proximity potential model for deformed nuclei

NASA Astrophysics Data System (ADS)

Santhosh, K. P.; Sukumaran, Indu

2017-09-01

Half-life predictions have been performed for the proton emitters with Z >50 in the ground state and isomeric state using the Coulomb and proximity potential model for deformed nuclei (CPPMDN). The agreement of the calculated values with the experimental data made it possible to predict some proton emissions that are not verified experimentally yet. For a comparison, the calculations also are performed using other theoretical models, such as the Gamow-like model of Zdeb et al. [Eur. Phys. J. A 52, 323 (2016), 10.1140/epja/i2016-16323-7], the semiempirical relation of Hatsukawa et al. [Phys. Rev. C 42, 674 (1990), 10.1103/PhysRevC.42.674], and the CPPM of Santhosh et al. [Pramana 58, 611 (2002)], 10.1007/s12043-002-0019-2. The Geiger-Nuttall law, originally observed for α decay, studied for proton radioactivity is found to work well provided it is plotted for the isotopes of a given proton emitter nuclide with the same ℓ value. The universal curve is found to be valid for proton radioactivity also as we obtained a single straight line for all proton emissions irrespective of the parents. Through the analysis of the experimentally measured half-lives of 44 proton emitters, the study revealed that the present systematic study lends support to a unified description for studying α decay, cluster radioactivity, and proton radioactivity.

The valence and Rydberg states of difluoromethane: A combined experimental vacuum ultraviolet spectrum absorption and theoretical study by ab initio configuration interaction and density functional computations

NASA Astrophysics Data System (ADS)

Palmer, Michael H.; Vrønning Hoffmann, Søren; Jones, Nykola C.; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare

2018-06-01

The vacuum ultraviolet (VUV) spectrum for CH2F2 from a new synchrotron study has been combined with earlier data and subjected to detailed scrutiny. The onset of absorption, band I and also band IV, is resolved into broad vibrational peaks, which contrast with the continuous absorption previously claimed. A new theoretical analysis, using a combination of time dependent density functional theory (TDDFT) calculations and complete active space self-consistent field, leads to a major new interpretation. Adiabatic excitation energies (AEEs) and vertical excitation energies, evaluated by these methods, are used to interpret the spectra in unprecedented detail using theoretical vibronic analysis. This includes both Franck-Condon (FC) and Herzberg-Teller (HT) effects on cold and hot bands. These results lead to the re-assignment of several known excited states and the identification of new ones. The lowest calculated AEE sequence for singlet states is 11B1 ˜ 11A2 < 21B1 < 11A1 < 21A1 < 11B2 < 31A1 < 31B1. These, together with calculated higher energy states, give a satisfactory account of the principal maxima observed in the VUV spectrum. Basis sets up to quadruple zeta valence with extensive polarization are used. The diffuse functions within this type of basis generate both valence and low-lying Rydberg excited states. The optimum position for the site of further diffuse functions in the calculations of Rydberg states is shown to lie on the H-atoms. The routine choice on the F-atoms is shown to be inadequate for both CHF3 and CH2F2. The lowest excitation energy region has mixed valence and Rydberg character. TDDFT calculations show that the unusual structure of the onset arises from the near degeneracy of 11B1 and 11A2 valence states, which mix in symmetric and antisymmetric combinations. The absence of fluorescence in the 10.8-11 eV region contrasts with strong absorption. This is interpreted by the 21B1 and 11A1 states where no fluorescence is calculated for these

Search for weak M 1 transitions in 48Ca with inelastic proton scattering

NASA Astrophysics Data System (ADS)

Mathy, M.; Birkhan, J.; Matsubara, H.; von Neumann-Cosel, P.; Pietralla, N.; Ponomarev, V. Yu.; Richter, A.; Tamii, A.

2017-05-01

Background: The quenching of spin-isospin modes in nuclei is an important field of research in nuclear structure. It has an impact on astrophysical reaction rates and on fundamental processes like neutrinoless double-β decay. Gamow-Teller (GT) and spin-flip M 1 strengths are quenched. Concerning the latter, the Jπ=1+ resonance in the doubly magic nucleus 48Ca, dominated by a single transition, serves as a reference case. Purpose: The aim of the present work is to search for weak M 1 transitions in 48Ca with a high-resolution (p ,p') experiment at 295 MeV and forward angles including 0∘ and a comparison with results from a similar study using backward-angle electron scattering at low momentum transfers in order to estimate their contribution to the total B (M 1 ) strength in 48Ca. Methods: The spin-M 1 cross sections of individual peaks in the spectra are deduced with a multipole decomposition analysis (MDA) and converted to reduced spin-M 1 transition strengths by using the unit cross-section method. For a comparison with electron-scattering results, corresponding reduced B (M 1 ) transition strengths are extracted following the approach outlined in Birkhan et al. [Phys. Rev. C 93, 041302(R) (2016), 10.1103/PhysRevC.93.041302]. Results: In total, 30 peaks containing a M 1 contribution are found in the excitation energy region 7-13 MeV. The resulting B (M 1 ) strength distribution compares well to the electron-scattering results considering different factors limiting the sensitivity in both experiments and the enhanced importance of mechanisms breaking the proportionality of nuclear cross sections and electromagnetic matrix elements for weak transitions as studied here. The total strength of 1.14(7) μN2 deduced assuming a nonquenched isoscalar part of the (p ,p') cross sections agrees with the (e ,e') result of 1.21(13) μN2. A bin-wise analysis above 10 MeV provides an upper limit of 1.51(17) μN2. Conclusions: The present results confirm the previous electron

Plasma-assisted reduction of silver ions impregnated into a natural zeolite framework

NASA Astrophysics Data System (ADS)

Osonio, Airah P.; Vasquez, Magdaleno R.

2018-02-01

A green, dry, and energy-efficient method for the fabrication of silver-zeolite (AgZ) composite via 13.56 MHz radio-frequency plasma reduction is demonstrated. Impregnation by soaking and ion-exchange deposition were performed to load the silver ions (Ag+) into the sodium-zeolite samples. Characterization was performed by optical emission spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and Brunauer-Emmett-Teller analyses. Results indicate the successful reduction of Ag+ to its metallic state on the surface of the zeolite with a mean diameter of 165 nm. This plasma-induced reduction technique opens possibilities in several areas including catalysis, adsorption, water treatment, and medicine.

Distorted allotropes of bi-benzene: vibronic interactions and electronic excitations

NASA Astrophysics Data System (ADS)

Krasnenko, V.; Boltrushko, V.; Hizhnyakov, V.

2017-05-01

Bi-benzene - chemically bound two benzene molecules in stuck position is studied both analytically and numerically. There are several allotropes of bi-benzene having different geometry. The reason of the existence of sundry distorted structures is the pseudo-Jahn-Teller effect. The parameters of vibronic couplings causing distortions are found. For the calculation of these parameters both, the vibronic coupling of carbon atoms in different C6 rings and the vibronic coupling in the rings are considered. The contribution of the distortion of C6-planes to the latter coupling is also found. The energies of all the electronic states of π-electrons in all bi-benzene allotropes are determined by using the calculated vibronic interaction parameters.

DFT calculations of the structures and vibrational spectra of the [Fe(bpy) 3] 2+ and [Ru(bpy) 3] 2+ complexes

NASA Astrophysics Data System (ADS)

Alexander, Bruce D.; Dines, Trevor J.; Longhurst, Rayne W.

2008-09-01

Structures of the [M(bpy) 3] 2+ complexes (M = Fe and Ru) have been calculated at the B3-LYP/DZVP level. IR and Raman spectra were calculated using the optimised geometries, employing a scaled quantum chemical force field, and compared with an earlier normal coordinate analysis of [Ru(bpy) 3] 2+ which was based upon experimental data alone, and the use of a simplified model. The results of the calculations provide a highly satisfactory fit to the experimental data and the normal coordinate analyses, in terms of potential energy distributions, allow a detailed understanding of the vibrational spectra of both complexes. Evidence is presented for Jahn-Teller distortion in the 1E MLCT excited state.

B2FH, the Cosmic Microwave Background and Cosmology*

NASA Astrophysics Data System (ADS)

Burbidge, G.

In this talk I shall start by describing how we set about and carried out the work that led to the publication of Burbidge et al. (1957, hereafter B2FH). I then shall try and relate this work and the circumstances that surrounded it to the larger problem of the origin and formation of the universe. Here it is necessary to look back at the way that ideas developed and how, in many situations, astronomers went astray. Of course this is a personal view, though I very strongly believe that if he were still here, it is the approach that Fred Hoyle would take. I start by describing the problems originally encountered by Gamow and his associates in trying to decide where the helium was made. This leads me to a modern discussion of the origin of 2D, 3He, 4He and 7Li, originally described by B2FH as due to the x-process. While it is generally argued, following Gamow, Alpher, and Herman, that these isotopes were synthesised in a big bang I shall show that it is equally likely that these isotopes were made in active galactic nuclei, as was the cosmic microwave background (CMB), in a cyclic universe model. The key piece of observational evidence is that the amount of energy released in the conversion of hydrogen to helium in the universe is very close to the energy carried by the CMB, namely ~4.5 × 10-13 erg cm-3.

Theoretical formulation of optical conductivity of La0.7Ca0.3MnO3 exhibiting paramagnetic insulator - ferromagnetic metal transition

NASA Astrophysics Data System (ADS)

Satiawati, L.; Majidi, M. A.

2017-07-01

A theory of high-energy optical conductivity of La0.7Ca0.3MnO3 has been proposed previously. The proposed theory works to explain the temperature-dependence of the optical conductivity for the photon energy region above ˜0.5 eV for up to ˜22 eV, but fails to capture the correct physics close to the dc limit in which metal-insulator transition occurs. The missing physics at the low energy has been acknowledged as mainly due to not incorporating phonon degree of freedom and electron-phonon interactions. In this study, we aim to complete the above theory by proposing a more complete Hamiltonian incorporating additional terms such as crystal field, two modes of Jahn-Teller vibrations, and coupling between electrons and the two Jahn-Teller vibrational modes. We solve the model by means of dynamical mean-field theory. At this stage, we aim to derive the analytical formulae involved in the calculation, and formulate the algorithmic implementation for the self-consistent calculation process. Our final goal is to compute the density of states and the optical conductivity for the complete photon energy range from 0 to 22 eV at various temperatures, and compare them with the experimental data. We expect that the improved model preserves the correct temperature-dependent physics at high photon energies, as already captured by the previous model, while it would also reveal ferromagnetic metal - paramagnetic insulator transition at the dc limit.

T-Pattern Analysis and Cognitive Load Manipulation to Detect Low-Stake Lies: An Exploratory Study.

PubMed

Diana, Barbara; Zurloni, Valentino; Elia, Massimiliano; Cavalera, Cesare; Realdon, Olivia; Jonsson, Gudberg K; Anguera, M Teresa

2018-01-01

Deception has evolved to become a fundamental aspect of human interaction. Despite the prolonged efforts in many disciplines, there has been no definite finding of a univocally "deceptive" signal. This work proposes an approach to deception detection combining cognitive load manipulation and T-pattern methodology with the objective of: (a) testing the efficacy of dual task-procedure in enhancing differences between truth tellers and liars in a low-stakes situation; (b) exploring the efficacy of T-pattern methodology in discriminating truthful reports from deceitful ones in a low-stakes situation; (c) setting the experimental design and procedure for following research. We manipulated cognitive load to enhance differences between truth tellers and liars, because of the low-stakes lies involved in our experiment. We conducted an experimental study with a convenience sample of 40 students. We carried out a first analysis on the behaviors' frequencies coded through the observation software, using SPSS (22). The aim was to describe shape and characteristics of behavior's distributions and explore differences between groups. Datasets were then analyzed with Theme 6.0 software which detects repeated patterns (T-patterns) of coded events (non-verbal behaviors) that regularly or irregularly occur within a period of observation. A descriptive analysis on T-pattern frequencies was carried out to explore differences between groups. An in-depth analysis on more complex patterns was performed to get qualitative information on the behavior structure expressed by the participants. Results show that the dual-task procedure enhances differences observed between liars and truth tellers with T-pattern methodology; moreover, T-pattern detection reveals a higher variety and complexity of behavior in truth tellers than in liars. These findings support the combination of cognitive load manipulation and T-pattern methodology for deception detection in low-stakes situations, suggesting the

T-Pattern Analysis and Cognitive Load Manipulation to Detect Low-Stake Lies: An Exploratory Study

PubMed Central

Diana, Barbara; Zurloni, Valentino; Elia, Massimiliano; Cavalera, Cesare; Realdon, Olivia; Jonsson, Gudberg K.; Anguera, M. Teresa

2018-01-01

Deception has evolved to become a fundamental aspect of human interaction. Despite the prolonged efforts in many disciplines, there has been no definite finding of a univocally “deceptive” signal. This work proposes an approach to deception detection combining cognitive load manipulation and T-pattern methodology with the objective of: (a) testing the efficacy of dual task-procedure in enhancing differences between truth tellers and liars in a low-stakes situation; (b) exploring the efficacy of T-pattern methodology in discriminating truthful reports from deceitful ones in a low-stakes situation; (c) setting the experimental design and procedure for following research. We manipulated cognitive load to enhance differences between truth tellers and liars, because of the low-stakes lies involved in our experiment. We conducted an experimental study with a convenience sample of 40 students. We carried out a first analysis on the behaviors’ frequencies coded through the observation software, using SPSS (22). The aim was to describe shape and characteristics of behavior’s distributions and explore differences between groups. Datasets were then analyzed with Theme 6.0 software which detects repeated patterns (T-patterns) of coded events (non-verbal behaviors) that regularly or irregularly occur within a period of observation. A descriptive analysis on T-pattern frequencies was carried out to explore differences between groups. An in-depth analysis on more complex patterns was performed to get qualitative information on the behavior structure expressed by the participants. Results show that the dual-task procedure enhances differences observed between liars and truth tellers with T-pattern methodology; moreover, T-pattern detection reveals a higher variety and complexity of behavior in truth tellers than in liars. These findings support the combination of cognitive load manipulation and T-pattern methodology for deception detection in low-stakes situations

Collective efficacy versus self-efficacy in coping responses to stressors and control: a cross-cultural study.

PubMed

Schaubroeck, J; Lam, S S; Xie, J L

2000-08-01

This study examined how cultural differences and efficacy perceptions influence the role of job control in coping with job demands. Perceiving higher control mitigated the effects of demands on psychological health symptoms and turnover intentions only among American bank tellers reporting high job self-efficacy. Among American tellers reporting low job self-efficacy, perceived control exacerbated the effects of demands. However, in a matched Hong Kong sample, collective efficacy interacted in the same way with control and demands as job self-efficacy had in the American sample. These differences appear to be explained by the individual attributes of idiocentrism and allocentrism that are linked to the societal norms of individualism and collectivism, respectively.

Effect of complex configurations on the description of properties of {sup 132}Sn beta decay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Severyukhin, A. P., E-mail: sever@theor.jinr.ru; Sushenok, E. O.

2015-07-15

Gamow–Teller transitions in the beta decay of the {sup 132}Sn neutron-rich nucleus was described microscopically. The coupling of one- and two-phonon components of the wave functions was taken into account on the basis of Skyrme interactions featuring various contributions of the tensor component. A separable approximation of the particle—hole interaction made it possible tohole interaction perform calculations in a large configuration space. It was shown that an increase in the strength of the neutron—proton tensor interaction led to an increase in the energy of Gamow—Teller transitions. In addition, a decrease in the {sup 132}Sn half-life with respect to beta decaymore » was obtained.« less

Coherent states: a contemporary panorama Coherent states: a contemporary panorama

NASA Astrophysics Data System (ADS)

Twareque Ali, S.; Antoine, Jean-Pierre; Bagarello, Fabio; Gazeau, Jean-Pierre

2012-06-01

magnetic field (Hall-Mitchell) a paper on CS for a quantum particle on a Möbius strip (Cirilo-Lombardo) a discussion of quantization on the circle (Chadzitaskos et al); SUSY CS for Pöschl-Teller potentials (Bergeron et al); generalized Bargmann functions and von Neumann lattices (Vourdas et al); partial reconstruction for a finite CS system, using the Fock-Bargmann representation (Calixto et al); phase operators for SU(3) irreps, thus for finite quantum systems (de Guise); semiclassical CS in periodic potentials (Carles-Sparber) complexified CS with non-Hermitian Hamiltonians (Graefe-Schubert) minimal uncertainty states in the context of (semisimple) group representation theory (Oszmaniec); localization operators in the time-frequency domain, i.e., in Gabor analysis (Muzhikyan-Avanesyan) and, finally, two papers about fermionic CS (Daoud-Kibler and Trifonov). This brief description illustrates perfectly the extreme versatility of the CS concept. As already stressed, coherent states constitute nowadays a flourishing research topic, with applications to a wide spectrum of domains. Indeed, CS are everywhere in physics: condensed matter physics, atomic physics, nuclear and particle physics, quantum optics, dynamics—both quantum and classical potentials—quantum gravity, quantization and quantum information theory. On the other hand, CS have grown into a fully-fledged domain in mathematics, incorporating many tools such as group representations, POV measures, frames, holomorphic functions, orthogonal polynomials and so on. Interestingly enough, the majority of contributions to this special issue (22 out of 37) are mathematically minded, demonstrating the widespread interest CS have generated in various areas of mathematics. A third field related to CS (but almost not represented in the present collection) is signal processing. Indeed both Gabor analysis and wavelet analysis derive in the first place from CS theory, namely, CS associated to the Weyl-Heisenberg and the ax

What happened in 1948?

NASA Astrophysics Data System (ADS)

Peebles, P. J.

2014-01-01

The idea that the universe is filled with the sea of thermal radiation now termed the Cosmic Microwave Background was first discussed in eleven publications in the year 1948 by Alpher, Herman, and Gamow. Precision measurements of this radiation are a central part of the evidence establishing the relativistic hot Big Bang theory of the expanding universe. The eleven 1948 papers offer a fascinating illustration of the exploration of a new line of research, and the confusion that can attend it. That includes a common misunderstanding of the considerations that led to the idea of this thermal radiation.

Adsorption of water vapour and the specific surface area of arctic zone soils (Spitsbergen)

NASA Astrophysics Data System (ADS)

Cieśla, Jolanta; Sokołowska, Zofia; Witkowska-Walczak, Barbara; Skic, Kamil

2018-01-01

Water vapour/nitrogen adsorption were investigated and calculated the specific surface areas of arctic-zone soil samples (Turbic Cryosols) originating from different micro-relief forms (mud boils, cell forms and sorted circles) and from different depths. For the characterisation of the isotherms obtained for arctic soils, the Brunauer-Emmet-Teller model was then compared with the two other models (Aranovich-Donohue and Guggenheim-Anderson-de Boer) which were developed from Brunauer-Emmet-Teller. Specific surface area was calculated using the Brunauer-Emmet-Teller model at p p0-1 range of 0.05-0.35 for the water vapour desorption and nitrogen adsorption isotherms. The values of total specific surface area were the highest in Cryosols on mud boils, lower on cell forms, and the lowest on sorted circles. Such tendency was observed for the results obtained by both the water vapour and nitrogen adsorption. The differences in the values of specific surface area at two investigated layers were small. High determination coefficients were obtained for relationships between the specific surface areas and contents of clay and silt fraction in Cryosols. No statistically significant correlation between the total carbon amount and the values of specific surface area in Cryosols has been found.

A reverse order interview does not aid deception detection regarding intentions

PubMed Central

Fenn, Elise; McGuire, Mollie; Langben, Sara; Blandón-Gitlin, Iris

2015-01-01

Promising recent research suggests that more cognitively demanding interviews improve deception detection accuracy. Would these cognitively demanding techniques work in the same way when discriminating between true and false future intentions? In Experiment 1 participants planned to complete a task, but instead were intercepted and interviewed about their intentions. Participants lied or told the truth, and were subjected to high (reverse order) or low (sequential order) cognitive load interviews. Third-party observers watched these interviews and indicated whether they thought the person was lying or telling the truth. Subjecting participants to a reverse compared to sequential interview increased the misidentification rate and the appearance of cognitive load in truth tellers. People lying about false intentions were not better identified. In Experiment 2, a second set of third-party observers rated behavioral cues. Consistent with Experiment 1, truth tellers, but not liars, exhibited more behaviors associated with lying and fewer behaviors associated with truth telling in the reverse than sequential interview. Together these results suggest that certain cognitively demanding interviews may be less useful when interviewing to detect false intentions. Explaining a true intention while under higher cognitive demand places truth tellers at risk of being misclassified. There may be such a thing as too much cognitive load induced by certain techniques PMID:26379610

A reverse order interview does not aid deception detection regarding intentions.

PubMed

Fenn, Elise; McGuire, Mollie; Langben, Sara; Blandón-Gitlin, Iris

2015-01-01

Promising recent research suggests that more cognitively demanding interviews improve deception detection accuracy. Would these cognitively demanding techniques work in the same way when discriminating between true and false future intentions? In Experiment 1 participants planned to complete a task, but instead were intercepted and interviewed about their intentions. Participants lied or told the truth, and were subjected to high (reverse order) or low (sequential order) cognitive load interviews. Third-party observers watched these interviews and indicated whether they thought the person was lying or telling the truth. Subjecting participants to a reverse compared to sequential interview increased the misidentification rate and the appearance of cognitive load in truth tellers. People lying about false intentions were not better identified. In Experiment 2, a second set of third-party observers rated behavioral cues. Consistent with Experiment 1, truth tellers, but not liars, exhibited more behaviors associated with lying and fewer behaviors associated with truth telling in the reverse than sequential interview. Together these results suggest that certain cognitively demanding interviews may be less useful when interviewing to detect false intentions. Explaining a true intention while under higher cognitive demand places truth tellers at risk of being misclassified. There may be such a thing as too much cognitive load induced by certain techniques.

Nematic phase in the CE-regime of colossal magnetoresistive manganites

NASA Astrophysics Data System (ADS)

Ochoa, Emily; Sen, Cengiz; Dagotto, Elbio; Lamar/UTK Collaboration

We report nematic phase tendencies around the first order CE transition in the two-orbital double exchange model with Jahn-Teller phonons at electronic density n = 0 . 5 . Starting with a random state at high temperatures, we employ a careful cool-down method using a Monte Carlo algorithm. We then monitor the spin structure factor S (q) of the CE phase as a function of temperature. Near the critical temperature, S (q) grows with decreasing temperature for both right- and left-ordered CE ladders, followed by a spontaneous symmetry breaking into one or the other as the critical temperature is achieved. Below the critical temperature a pure CE state with a staggered charge order is obtained. Our results are similar to those observed in pnictides in earlier studies. Lamar University Office of Undergraduate Research, and U.S. Department of Energy, Office of Basic Energy Sciences, Materials Sciences and Engineering Division.

Vibronic bands in the HOMO-LUMO excitation of linear polyyne molecules

NASA Astrophysics Data System (ADS)

Wakabayashi, Tomonari; Wada, Yoriko; Iwahara, Naoya; Sato, Tohru

2013-04-01

Hydrogen-capped linear carbon chain molecules, namely polyynes H(C≡C)nH (n>=2), give rise to three excited states in the HOMO-LUMO excitation. Electric dipole transition from the ground state is fully allowed to one of the three excited states, while forbidden for the other two low-lying excited states. In addition to the strong absorption bands in the UV for the allowed transition, the molecules exhibit weak absorption and emission bands in the near UV and visible wavelength regions. The weak features are the vibronic bands in the forbidden transition. In this article, symmetry considerations are presented for the optical transitions in the centrosymmetric linear polyyne molecule. The argument includes Herzberg-Teller expansion for the state mixing induced by nuclear displacements along the normal coordinate of the molecule, intensity borrowing from fully allowed transitions, and inducing vibrational modes excited in the vibronic transition. The vibronic coupling considered here includes off-diagonal matrix elements for second derivatives along the normal coordinate. The vibronic selection rule for the forbidden transition is derived and associated with the transition moment with respect to the molecular axis. Experimental approaches are proposed for the assignment of the observed vibronic bands.

Vibronic Structure of the tilde{X} ^2A_2' State of NO_3

NASA Astrophysics Data System (ADS)

Fukushima, Masaru

2015-06-01

We have measured dispersed fluorescence ( DF ) spectra from the single vibronic levels ( SVL's ) of the tilde{B} ^2E' state of jet cooled 14NO_3 and 15NO_3, and found a new vibronic band around the ν_1 fundamental This new band has two characteristics; (1) inverse isotope shift, and (2) unexpectedly strong intensity, i.e. comparable with that of the ν_1 fundamental. We concluded on the basis of the isotope effect that the terminated ( lower ) vibrational level of the new vibronic band should have vibrationally a_1' symmetry, and assigned to the third over-tone of the ν_4 asymmetric (e') mode, 3 ν_4 (a_1'). We also assigned a weaker band at about 160 cm-1 above the new band to one terminated to 3 ν_4 (a_2'). The 3 ν_4 (a_1') and (a_2') levels are ones with l = ±3. Hirota proposed new vibronic coupling mechanism which suggests that degenerate vibrational modes can induce electronic orbital angular momentum ( L ) even in non-degenerate electronic states. %It is thus thought the surprisingly wide splitting of 3 ν_4, a_1' and a_2', is resulted from vibronic coupling, and the explanation we proposed is as follows. We interpret this as a sort of break-down of the Born-Oppenheimer approximation, and think that ± l induces ∓barΛ, where barΛ expresses the pseudo-L; for the present system, one of the components of the third over-tone level, | Λ = 0; v_4 = 3, l = +3 rangle, can have contributions of | barΛ = -1; v_4 = 3, l = +2 rangle and | -2; 3, +1 rangle. Under this interpretation, it is expected that there is sixth-order vibronic coupling, (q_+^3Q_-^3 + q_-^3Q_+^3), between | 0; 3, +3 rangle and | 0; 3, -3 rangle. The sixth-order coupling is weaker than the Renner-Teller term ( the fourth-order term, (q_+^2Q_-^2 + q_-^2Q_+^2) ), but stronger than the eighth-order term, (q_+^4Q_-^4 + q_-^4Q_+^4). It is well known in linear molecules that the former shows huge separation, comparable with vibrational frequency, among the vibronic levels of Π electronic states

State of the States 2016: Arts Education State Policy Summary

ERIC Educational Resources Information Center

Aragon, Stephanie

2016-01-01

The "State of the States 2016" summarizes state policies for arts education identified in statute or administrative code for all 50 states and the District of Columbia. Information is based on a comprehensive search of state education statute and codes on each state's relevant websites. Complete results from this review are available in…

Evidence of Photo-induced Dynamic Competition of Metallic and Insulating Phase in a Layered Manganite.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yuelin; Walko, Donald A.; Li, Qing'an

2015-12-16

We show evidence that the competition between the antiferromagetic metallic phase and the charge- and orbital-ordered insulating phase at the reentrant phase boundary of a layered manganite, LaSr2Mn2O7, can be manipulated using ultrafast optical excitation. The time- dependent evolution of the Jahn-Teller superlattice reflection, which indicates the formation of the charge and orbital order, was measured at different laser fluences. The laser-induced enhancement and reduction the Jahn-Teller reflection intensity shows a reversal of sign between earlier (~10 ns) and later (~150 ns) time delays during the relaxation after photo excitation. This effect is consistent with a scenario whereby the lasermore » excitation modulates the local competition between the metallic and the insulating phases.« less

Evidence of photo-induced dynamic competition of metallic and insulating phase in a layered manganite

DOE PAGES

Li, Yuelin; Walko, Daonld A.; Li, Qing'an; ...

2015-11-17

We show evidence that the competition between the antiferromagetic metallic phase and the charge- and orbital-ordered insulating phase at the reentrant phase boundary of a layered manganite, LaSr 2Mn 2O 7, can be manipulated using ultrafast optical excitation. The time-dependent evolution of the Jahn-Teller superlattice reflection, which indicates the formation of the charge and orbital order, was measured at different laser fluences. The laser-induced enhancement and reduction the Jahn-Teller reflection intensity shows a reversal of sign between earlier (~10 ns) and later (~150 ns) time delays during the relaxation after photo excitation. This effect is consistent with a scenario wherebymore » the laser excitation modulates the local competition between the metallic and the insulating phases.« less

State of the States, 2012: Arts Education State Policy Summary

ERIC Educational Resources Information Center

Arts Education Partnership (NJ1), 2012

2012-01-01

The "State of the States 2012" summarizes state policies for arts education identified in statute or code for all 50 states and the District of Columbia. Information is based primarily on results from the AEP Arts Education State Policy Survey conducted in 2010-11, and updated in April 2012.

Structure-dependent photophysical properties of singlet and triplet metal-to-ligand charge transfer states in copper(I) bis(diimine) compounds.

PubMed

Siddique, Zainul Abedin; Yamamoto, Yuichi; Ohno, Takeshi; Nozaki, Koichi

2003-10-06

The photophysical properties of singlet and triplet metal-to-ligand charge transfer (MLCT) states of [Cu(I)(diimine)(2)](+), where diimine is 2,9-dimethyl-1,10-phenanthroline (dmphen), 2,9-dibutyl-1,10-phenanthroline (dbphen), or 6,6'-dimethyl-2,2'-bipyridine (dmbpy), were studied. On 400 nm laser excitation of [Cu(dmphen)(2)](+) in CH(2)Cl(2) solution, prompt (1)MLCT fluorescence with a quantum yield of (2.8 +/- 0.8) x 10(-5) was observed using a picosecond time-correlated single photon counting technique. The quantum yield was dependent on the excitation wavelength, suggesting that relaxation of the Franck-Condon state to the lowest (1)MLCT competes with rapid intersystem crossing (ISC). The fluorescence lifetime of the copper(I) compound was 13-16 ps, unexpectedly long despite a large spin-orbit coupling constant of 3d electrons in copper (829 cm(-1) ). Quantum chemical calculations using a density functional theory revealed that the structure of the lowest (1)MLCT in [Cu(dmphen)(2)](+) (1(1)B(1)) was flattened due to the Jahn-Teller effect in 3d(9) electronic configuration, and the dihedral angle between the two phenanthroline planes (dha) was about 75 degrees with the dha around 90 degrees in the ground state. Intramolecular reorganization energy for the radiative transition of 1(1)B(1) was calculated as 2.1 x 10(3) cm(-1), which is responsible for the large Stokes shift of the fluorescence observed (5.4 x 10(3) cm(-1)). To understand the sluggishness of the intersystem crossing (ISC) of (1)MLCT of the copper(I) compounds, the strength of the spin-orbit interaction between the lowest (1)MLCT (1(1)B(1)) and all (3)MLCT states was calculated. The ISC channels induced by strong spin-orbit interactions (ca. 300 cm(-1)) between the metal-centered HOMO and HOMO - 1 were shown to be energetically unfavorable in the copper(I) compounds because the flattening distortion caused large splitting (6.9 x 10(3) cm(-1)) between these orbitals. The possible ISC is therefore

Orbital Dimer Model for the Spin-Glass State in Y_{2}Mo_{2}O_{7}.

PubMed

Thygesen, Peter M M; Paddison, Joseph A M; Zhang, Ronghuan; Beyer, Kevin A; Chapman, Karena W; Playford, Helen Y; Tucker, Matthew G; Keen, David A; Hayward, Michael A; Goodwin, Andrew L

2017-02-10

The formation of a spin glass generally requires that magnetic exchange interactions are both frustrated and disordered. Consequently, the origin of spin-glass behavior in Y_{2}Mo_{2}O_{7}-in which magnetic Mo^{4+} ions occupy a frustrated pyrochlore lattice with minimal compositional disorder-has been a longstanding question. Here, we use neutron and x-ray pair-distribution function (PDF) analysis to develop a disorder model that resolves apparent incompatibilities between previously reported PDF, extended x-ray-absorption fine structure spectroscopy, and NMR studies, and provides a new and physical explanation of the exchange disorder responsible for spin-glass formation. We show that Mo^{4+} ions displace according to a local "two-in-two-out" rule on each Mo_{4} tetrahedron, driven by orbital dimerization of Jahn-Teller active Mo^{4+} ions. Long-range orbital order is prevented by the macroscopic degeneracy of dimer coverings permitted by the pyrochlore lattice. Cooperative O^{2-} displacements yield a distribution of Mo-O-Mo angles, which in turn introduces disorder into magnetic interactions. Our study demonstrates experimentally how frustration of atomic displacements can assume the role of compositional disorder in driving a spin-glass transition.

Effect of Jahn-Teller ion in zinc sodium sulphate hexahydrate: a case of low hyperfine coupling constant for Cu(II) ion

NASA Astrophysics Data System (ADS)

Naidu, K. C.; Shiyamala, C.; Mithira, S.; Natarajan, B.; Venkatesan, R.; Rao, P. S.

2005-06-01

Single crystal electron paramagnetic resonance (EPR) studies of Cu(II) doped zinc sodium sulphate hexahydrate are carried out from room temperature (RT) to 123 K. The RT spectra show unresolved hyperfine lines and hence angular variation studies are also carried out at 123 K to obtain spin Hamiltonian parameters. The spin Hamiltonian parameters calculated from the 123 K spectra are: g(11)=2.039, g(22)=2.232, g(33)=2.394, A(11)=5.64 mT, A(22)=4.20 mT, and A(33)=7.94 mT. The g-matrix values at RT and 123 K have matched fairly well with each other. The low hyperfine value (A(33)), obtained at 123 K, has been explained by considering considerable admixture of d(x 2-y 2) ground state with d(z 2) excited state and the delocalization of the unpaired spin density onto the ligands. The admixture coefficients of ground state wave function are: a=0.346, b=0.935, c=0.055, d=0.040, e=-0.040, where a and b correspond to admixture coefficients for d(z 2) and d(x 2-y 2), respectively. Angular variation of Cu(II) resonances in the three orthogonal axes shows that the impurity has entered a substitutional site in the host lattice in place of Zn(II). Bonding parameters, kappa=0.295, P=245.4x10(-4), alpha(2)=0.709, alpha=0.8421 and alpha'=0.6034, have also been calculated to fully characterize the EPR.

Upper critical field reaches 90 tesla near the Mott transition in fulleride superconductors

DOE PAGES

Kasahara, Y.; Takeuchi, Y.; Zadik, R. H.; ...

2017-02-17

Controlled access to the border of the Mott insulating state by variation of control parameters offers exotic electronic states such as anomalous and possibly high-transition-temperature (T c) superconductivity. The alkali-doped fullerides show a transition from a Mott insulator to a superconductor for the first time in three-dimensional materials, but the impact of dimensionality and electron correlation on superconducting properties has remained unclear. Here we show that, near the Mott insulating phase, the upper critical field H c2 of the fulleride superconductors reaches values as high as ~90 T—the highest among cubic crystals. This is accompanied by a crossover from weak-more » to strong-coupling superconductivity and appears upon entering the metallic state with the dynamical Jahn–Teller effect as the Mott transition is approached. Lastly, these results suggest that the cooperative interplay between molecular electronic structure and strong electron correlations plays a key role in realizing robust superconductivity with high-T c and high-H c2.« less

Upper critical field reaches 90 tesla near the Mott transition in fulleride superconductors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kasahara, Y.; Takeuchi, Y.; Zadik, R. H.

Controlled access to the border of the Mott insulating state by variation of control parameters offers exotic electronic states such as anomalous and possibly high-transition-temperature (T c) superconductivity. The alkali-doped fullerides show a transition from a Mott insulator to a superconductor for the first time in three-dimensional materials, but the impact of dimensionality and electron correlation on superconducting properties has remained unclear. Here we show that, near the Mott insulating phase, the upper critical field H c2 of the fulleride superconductors reaches values as high as ~90 T—the highest among cubic crystals. This is accompanied by a crossover from weak-more » to strong-coupling superconductivity and appears upon entering the metallic state with the dynamical Jahn–Teller effect as the Mott transition is approached. Lastly, these results suggest that the cooperative interplay between molecular electronic structure and strong electron correlations plays a key role in realizing robust superconductivity with high-T c and high-H c2.« less

A low noise discrete velocity method for the Boltzmann equation with quantized rotational and vibrational energy

NASA Astrophysics Data System (ADS)

Clarke, Peter; Varghese, Philip; Goldstein, David

2018-01-01

A discrete velocity method is developed for gas mixtures of diatomic molecules with both rotational and vibrational energy states. A full quantized model is described, and rotation-translation and vibration-translation energy exchanges are simulated using a Larsen-Borgnakke exchange model. Elastic and inelastic molecular interactions are modeled during every simulated collision to help produce smooth internal energy distributions. The method is verified by comparing simulations of homogeneous relaxation by our discrete velocity method to numerical solutions of the Jeans and Landau-Teller equations, and to direct simulation Monte Carlo. We compute the structure of a 1D shock using this method, and determine how the rotational energy distribution varies with spatial location in the shock and with position in velocity space.

One Dimensional(1D)-to-2D Crossover of Spin Correlations in the 3D Magnet ZnMn 2O 4

DOE PAGES

Disseler, S. M.; Chen, Y.; Yeo, S.; ...

2015-12-08

In this paper we report on the intriguing evolution of the dynamical spin correlations of the frustrated spinel ZnMn 2O 4. Inelastic neutron scattering and magnetization studies reveal that the dynamical correlations at high temperatures are 1D. At lower temperature, these dynamical correlations become 2D. Surprisingly, the dynamical correlations condense into a quasi 2D Ising-like ordered state, making this a rare observation of two dimensional order on the spinel lattice. Remarkably, 3D ordering is not observed down to temperatures as low as 300 mK. This unprecedented dimensional crossover stems from frustrated exchange couplings due to the huge Jahn-Teller distortions aroundmore » Mn 3+ ions on the spinel lattice.« less

Neural-Network Quantum States, String-Bond States, and Chiral Topological States

NASA Astrophysics Data System (ADS)

Glasser, Ivan; Pancotti, Nicola; August, Moritz; Rodriguez, Ivan D.; Cirac, J. Ignacio

2018-01-01

Neural-network quantum states have recently been introduced as an Ansatz for describing the wave function of quantum many-body systems. We show that there are strong connections between neural-network quantum states in the form of restricted Boltzmann machines and some classes of tensor-network states in arbitrary dimensions. In particular, we demonstrate that short-range restricted Boltzmann machines are entangled plaquette states, while fully connected restricted Boltzmann machines are string-bond states with a nonlocal geometry and low bond dimension. These results shed light on the underlying architecture of restricted Boltzmann machines and their efficiency at representing many-body quantum states. String-bond states also provide a generic way of enhancing the power of neural-network quantum states and a natural generalization to systems with larger local Hilbert space. We compare the advantages and drawbacks of these different classes of states and present a method to combine them together. This allows us to benefit from both the entanglement structure of tensor networks and the efficiency of neural-network quantum states into a single Ansatz capable of targeting the wave function of strongly correlated systems. While it remains a challenge to describe states with chiral topological order using traditional tensor networks, we show that, because of their nonlocal geometry, neural-network quantum states and their string-bond-state extension can describe a lattice fractional quantum Hall state exactly. In addition, we provide numerical evidence that neural-network quantum states can approximate a chiral spin liquid with better accuracy than entangled plaquette states and local string-bond states. Our results demonstrate the efficiency of neural networks to describe complex quantum wave functions and pave the way towards the use of string-bond states as a tool in more traditional machine-learning applications.

On the Numerical Analysis of Decay Rate Enhancement in Metallic Environment

NASA Astrophysics Data System (ADS)

Mehedinteanu, S.

2007-10-01

Motivated on the very recent experiments to determine the acceleration of the alpha decay of meta-stable radionuclides in metallic environment some work has been done to strengthten the importance in the process of electrons screening in metals. Thus, by combining the Gamow decay theory with electrostatic screening in Debye-Hückel approximation (jellium model) a formula for ``the shift'' in screening energy which enters in the decay enhancement factor expression that copes well with these experiments has been derived. It was established that to simulate the poly-atoms system containing decaying isotopes in QM&MD codes calculations, and to include ``the screening energy shift'' of protons, decay alpha, beta+ particles due to all surrounding interacting effects, it is sufficiently only to substitute the code ruly pseudo-potential input for hydrogen-like atoms (including alpha) by a screened Coulomb potential as from the well-known Gamow alpha decay theory. For demonstration is used the QM&MD code package which usually performs density-functional theory (DFT) total-energy calculations for materials ranging from insulators to transition metals. This package employs first-principles pseudo-potentials and a plane-wave basis-set, and it was used to do a special calculus for some metal environments (Pd) where protons-deuterons are implanted or when it is alloyed with a radionuclide-like isotopes (174Hf72), the results compare well with the existing experiments on the decay enhancement. These works give further arguments for a cheap solution to remove the transuranic waste (involving all alpha-decay) of used-up rods of fission reactors in a time period of a few years.

12 CFR 712.5 - What activities and services are preapproved for CUSOs?

Code of Federal Regulations, 2012 CFR

2012-01-01

... services: (1) Automated teller machine (ATM) services; (2) Credit card and debit card services; (3) Data... brokerage or agency: (1) Agency for sale of insurance; (2) Provision of vehicle warranty programs; (3...

12 CFR 712.5 - What activities and services are preapproved for CUSOs?

Code of Federal Regulations, 2014 CFR

2014-01-01

... services: (1) Automated teller machine (ATM) services; (2) Credit card and debit card services; (3) Data... brokerage or agency: (1) Agency for sale of insurance; (2) Provision of vehicle warranty programs; (3...

12 CFR 712.5 - What activities and services are preapproved for CUSOs?

Code of Federal Regulations, 2011 CFR

2011-01-01

... services: (1) Automated teller machine (ATM) services; (2) Credit card and debit card services; (3) Data... brokerage or agency: (1) Agency for sale of insurance; (2) Provision of vehicle warranty programs; (3...

12 CFR 712.5 - What activities and services are preapproved for CUSOs?

Code of Federal Regulations, 2013 CFR

2013-01-01

... services: (1) Automated teller machine (ATM) services; (2) Credit card and debit card services; (3) Data... brokerage or agency: (1) Agency for sale of insurance; (2) Provision of vehicle warranty programs; (3...

12 CFR 205.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... device means a card, code, or other means of access to a consumer's account, or any combination thereof..., automated teller machines, and cash dispensing machines. (i) Financial institution means a bank, savings...

12 CFR 205.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... device means a card, code, or other means of access to a consumer's account, or any combination thereof..., automated teller machines, and cash dispensing machines. (i) Financial institution means a bank, savings...

12 CFR 205.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... device means a card, code, or other means of access to a consumer's account, or any combination thereof..., automated teller machines, and cash dispensing machines. (i) Financial institution means a bank, savings...

12 CFR 205.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... device means a card, code, or other means of access to a consumer's account, or any combination thereof..., automated teller machines, and cash dispensing machines. (i) Financial institution means a bank, savings...

Electron–vibration coupling induced renormalization in the photoemission spectrum of diamondoids

DOE PAGES

Gali, Adam; Demján, Tamás; Vörös, Márton; ...

2016-04-22

The development of theories and methods devoted to the accurate calculation of the electronic quasi-particle states and levels of molecules, clusters and solids is of prime importance to interpret the experimental data. These quantum systems are often modelled by using the Born–Oppenheimer approximation where the coupling between the electrons and vibrational modes is not fully taken into account, and the electrons are treated as pure quasi-particles. Here, we show that in small diamond cages, called diamondoids, the electron–vibration coupling leads to the breakdown of the electron quasi-particle picture. More importantly, we demonstrate that the strong electron–vibration coupling is essential tomore » properly describe the overall lineshape of the experimental photoemission spectrum. This cannot be obtained by methods within Born–Oppenheimer approximation. Furthermore, we deduce a link between the vibronic states found by our many-body perturbation theory approach and the well-known Jahn–Teller effect.« less

Parametric symmetries in exactly solvable real and PT symmetric complex potentials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yadav, Rajesh Kumar, E-mail: rajeshastrophysics@gmail.com; Khare, Avinash, E-mail: khare@physics.unipune.ac.in; Bagchi, Bijan, E-mail: bbagchi123@gmail.com

In this paper, we discuss the parametric symmetries in different exactly solvable systems characterized by real or complex PT symmetric potentials. We focus our attention on the conventional potentials such as the generalized Pöschl Teller (GPT), Scarf-I, and PT symmetric Scarf-II which are invariant under certain parametric transformations. The resulting set of potentials is shown to yield a completely different behavior of the bound state solutions. Further, the supersymmetric partner potentials acquire different forms under such parametric transformations leading to new sets of exactly solvable real and PT symmetric complex potentials. These potentials are also observed to be shape invariantmore » (SI) in nature. We subsequently take up a study of the newly discovered rationally extended SI potentials, corresponding to the above mentioned conventional potentials, whose bound state solutions are associated with the exceptional orthogonal polynomials (EOPs). We discuss the transformations of the corresponding Casimir operator employing the properties of the so(2, 1) algebra.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gali, Adam; Demján, Tamás; Vörös, Márton

The development of theories and methods devoted to the accurate calculation of the electronic quasi-particle states and levels of molecules, clusters and solids is of prime importance to interpret the experimental data. These quantum systems are often modelled by using the Born–Oppenheimer approximation where the coupling between the electrons and vibrational modes is not fully taken into account, and the electrons are treated as pure quasi-particles. Here, we show that in small diamond cages, called diamondoids, the electron–vibration coupling leads to the breakdown of the electron quasi-particle picture. More importantly, we demonstrate that the strong electron–vibration coupling is essential tomore » properly describe the overall lineshape of the experimental photoemission spectrum. This cannot be obtained by methods within Born–Oppenheimer approximation. Furthermore, we deduce a link between the vibronic states found by our many-body perturbation theory approach and the well-known Jahn–Teller effect.« less

Electron–vibration coupling induced renormalization in the photoemission spectrum of diamondoids

PubMed Central

Gali, Adam; Demján, Tamás; Vörös, Márton; Thiering, Gergő; Cannuccia, Elena; Marini, Andrea

2016-01-01

The development of theories and methods devoted to the accurate calculation of the electronic quasi-particle states and levels of molecules, clusters and solids is of prime importance to interpret the experimental data. These quantum systems are often modelled by using the Born–Oppenheimer approximation where the coupling between the electrons and vibrational modes is not fully taken into account, and the electrons are treated as pure quasi-particles. Here, we show that in small diamond cages, called diamondoids, the electron–vibration coupling leads to the breakdown of the electron quasi-particle picture. More importantly, we demonstrate that the strong electron–vibration coupling is essential to properly describe the overall lineshape of the experimental photoemission spectrum. This cannot be obtained by methods within Born–Oppenheimer approximation. Moreover, we deduce a link between the vibronic states found by our many-body perturbation theory approach and the well-known Jahn–Teller effect. PMID:27103340

Pinning of topological solitons at extrinsic defects in a quasi one-dimensional charge density wave

NASA Astrophysics Data System (ADS)

Razzaq, Samad; Wippermann, Stefan; Tae Hwan Kim Collaboration; Han Woong Yeom Collaboration

Quasi one-dimensional (1D) electronic systems are known to exhibit exotic physical phenomena, such as, e.g., Jahn Teller distortions, charge density wave (CDW) formation and non-Fermi liquid behavior. Solitonic excitations of the charge density wave ordered ground state and associated topological edge states in atomic wires are presently the focus of increasing attention. We carried out a combined ab initio and scanning tunneling microscopy (STM) study of solitonic and non-solitonic phase defects in the In/Si(111) atomic wire array. While free solitons move too fast to be imaged directly in STM, they can become trapped at extrinsic de- fects within the wire. We discuss the detailed atomistic structure of the responsible extrinsic defects and trapped solitons. Our study highlights the key role of coupled theory-experimental investigations in order to understand also the elusive fast moving solitons. S. W. gratefully acknowledges financial support from the German Research Foundation (DFG), Grant No. FOR1700.

Unconscious deception detection measured by finger skin temperature and indirect veracity judgments-results of a registered report.

PubMed

van 't Veer, Anna E; Gallucci, Marcello; Stel, Mariëlle; van Beest, Ilja

2015-01-01

A pre-registered experiment was conducted to examine psychophysiological responses to being lied to. Bridging research on social cognition and deception detection, we hypothesized that observing a liar compared to a truth-teller would decrease finger skin temperature of observers. Participants first watched two targets while not forewarned that they would later be asked to judge (direct and indirect) veracity, and then watched another two targets while forewarned about this. During both these phases finger skin temperature was measured. Findings pertaining to temperature partly confirmed our main hypothesis. When participants were observing a liar, irrespective of being forewarned, on average finger skin temperature declined over time. In the forewarned phase, temperature trajectories of truth-tellers were higher than those of liars, however, in the not forewarned phase, this pattern was reversed. Results confirmed our further hypotheses that participants judge liars as less likeable and less trustworthy than truth-tellers-an indication of indirect deception detection. Our hypothesis that the effect size for trustworthiness would be bigger than that of liking was not supported by the data. Additionally, and also confirming our hypothesis, participants performed around chance level when directly judging whether the target person was lying. Exploratory analyses are reported with regard to truth bias and dependency between direct and indirect veracity judgments. Limitations and directions for future work related to the existence of psychophysiological indicators of deception detection are discussed.

Energy levels of one-dimensional systems satisfying the minimal length uncertainty relation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernardo, Reginald Christian S., E-mail: rcbernardo@nip.upd.edu.ph; Esguerra, Jose Perico H., E-mail: jesguerra@nip.upd.edu.ph

2016-10-15

The standard approach to calculating the energy levels for quantum systems satisfying the minimal length uncertainty relation is to solve an eigenvalue problem involving a fourth- or higher-order differential equation in quasiposition space. It is shown that the problem can be reformulated so that the energy levels of these systems can be obtained by solving only a second-order quasiposition eigenvalue equation. Through this formulation the energy levels are calculated for the following potentials: particle in a box, harmonic oscillator, Pöschl–Teller well, Gaussian well, and double-Gaussian well. For the particle in a box, the second-order quasiposition eigenvalue equation is a second-ordermore » differential equation with constant coefficients. For the harmonic oscillator, Pöschl–Teller well, Gaussian well, and double-Gaussian well, a method that involves using Wronskians has been used to solve the second-order quasiposition eigenvalue equation. It is observed for all of these quantum systems that the introduction of a nonzero minimal length uncertainty induces a positive shift in the energy levels. It is shown that the calculation of energy levels in systems satisfying the minimal length uncertainty relation is not limited to a small number of problems like particle in a box and the harmonic oscillator but can be extended to a wider class of problems involving potentials such as the Pöschl–Teller and Gaussian wells.« less

Excitations and relaxation dynamics in multiferroic GeV4S8 studied by terahertz and dielectric spectroscopy

NASA Astrophysics Data System (ADS)

Reschke, S.; Wang, Zhe; Mayr, F.; Ruff, E.; Lunkenheimer, P.; Tsurkan, V.; Loidl, A.

2017-10-01

We report on THz time-domain spectroscopy on multiferroic GeV4S8 , which undergoes orbital ordering at a Jahn-Teller transition at 30.5 K and exhibits antiferromagnetic order below 14.6 K. The THz experiments are complemented by dielectric experiments at audio and radio frequencies. We identify a low-lying excitation close to 0.5 THz, which is only weakly temperature dependent and probably corresponds to a molecular excitation within the electronic level scheme of the V4 clusters. In addition, we detect complex temperature-dependent behavior of a low-lying phononic excitation, closely linked to the onset of orbitally driven ferroelectricity. In the high-temperature cubic phase, which is paramagnetic and orbitally disordered, this excitation is of relaxational character becomes an overdamped Lorentzian mode in the orbitally ordered phase below the Jahn-Teller transition, and finally appears as well-defined phonon excitation in the antiferromagnetic state. Abrupt changes in the real and imaginary parts of the complex dielectric permittivity show that orbital ordering appears via a structural phase transition with strong first-order character and that the onset of antiferromagnetic order is accompanied by significant structural changes, which are of first-order character, too. Dielectric spectroscopy documents that at low frequencies, significant dipolar relaxations are present in the orbitally ordered, paramagnetic phase only. In contrast to the closely related GaV4S8 , this relaxation dynamics that most likely mirrors coupled orbital and polar fluctuations does not seem to be related to the dynamic processes detected in the THz regime.

Perovskite-structure TlMnO₃: a new manganite with new properties.

PubMed

Yi, Wei; Kumagai, Yu; Spaldin, Nicola A; Matsushita, Yoshitaka; Sato, Akira; Presniakov, Igor A; Sobolev, Alexey V; Glazkova, Yana S; Belik, Alexei A

2014-09-15

We synthesize a new member of the AMnO3 perovskite manganite family (where A is a trivalent cation)--thallium manganite, TlMnO3--under high-pressure (6 GPa) and high-temperature (1500 K) conditions and show that the structural and magnetic properties are distinct from those of all other AMnO3 manganites. The crystal structure of TlMnO3 is solved and refined using single-crystal X-ray diffraction data. We obtain a triclinically distorted structure with space group P1̅ (No. 2), Z = 4, and lattice parameters a = 5.4248(2) Å, b = 7.9403(2) Å, c = 5.28650(10) Å, α = 87.8200(10)°, β = 86.9440(10)°, and γ = 89.3130(10)° at 293 K. There are four crystallographic Mn sites in TlMnO3 forming two groups based on the degree of their Jahn-Teller distortions. Physical properties of insulating TlMnO3 are investigated with Mössbauer spectroscopy and resistivity, specific heat, and magnetization measurements. The orbital ordering, which persists to the decomposition temperature of 820 K, suggests A-type antiferromagnetic ordering with the ferromagnetic planes along the [-101] direction, consistent with the measured collinear antiferromagnetism below the Néel temperature of 92 K. Hybrid density functional calculations are consistent with the experimentally identified structure, insulating ground state, and suggested magnetism, and show that the low symmetry originates from the strongly Jahn-Teller distorted Mn(3+) ions combined with the strong covalency of the Tl(3+)-O bonds.

The Martians of Science - Five Physicists Who Changed the Twentieth Century

NASA Astrophysics Data System (ADS)

Hargittai, István

2006-07-01

If science has the equivalent of a Bloomsbury group, it is the five men born at the turn of the twentieth century in Budapest: Theodore von Kármán, Leo Szilard, Eugene Wigner, John von Neumann, and Edward Teller. From Hungary to Germany to the United States, they remained friends and continued to work together and influence each other throughout their lives. As a result, their work was integral to some of the most important scientific and political developments of the twentieth century. They were an extraordinary group of talents: Wigner won a Nobel Prize in theoretical physics; Szilard was the first to see that a chain reaction based on neutrons was possible, initiated the Manhattan Project, but left physics to try to restrict nuclear arms; von Neumann could solve difficult problems in his head and developed the modern computer for more complex problems; von Kármán became the first director of NASA's Jet Propulsion Laboratory, providing the scientific basis for the U.S. Air Force; and Teller was the father of the hydrogen bomb, whose name is now synonymous with the controversial "Star Wars" initiative of the 1980s. Each was fiercely opinionated, politically active, and fought against all forms of totalitarianism. István Hargittai, as a young Hungarian physical chemist, was able to get to know some of these great men in their later years, and the depth of information and human interest in The Martians of Science is the result of his personal relationships with the subjects, their families, and their contemporaries.

Norris Bradbury and Edward Teller: A Fission-Fusion Reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meade, Roger Allen

On a bright, sunny day in October 1945, a boisterous and jubilant crowd assembled in front of Fuller Lodge to watch as the Army-Navy “E” Award, a prestigious national honor given for “Excellence in Production” during World War II, was presented to the Los Alamos Laboratory. Major General Leslie Groves, the commanding officer of the Manhattan Project; Navy Commodore William S. (Deak) Parsons, the wartime leader of the Laboratory’s Ordnance Division; Robert Sproul, the President of the University of California; and J. Robert Oppenheimer accepted the award on behalf of the Laboratory.

12 CFR 205.16 - Disclosures at automated teller machines.

Code of Federal Regulations, 2010 CFR

2010-01-01

... which a consumer initiates an electronic fund transfer or a balance inquiry and that does not hold the account to or from which the transfer is made, or about which an inquiry is made. (b) General. An... transfer or a balance inquiry shall: (1) Provide notice that a fee will be imposed for providing electronic...

Half-Lives of Proton Emitters With a Deformed Density-Dependent Model

NASA Astrophysics Data System (ADS)

Qian, Yi-Bin; Ren, Zhong-Zhou; Ni, Dong-Dong; Sheng, Zong-Qiang

2010-11-01

Half-lives of proton radioactivity are investigated with a deformed density-dependent model. The single folding potential which is dependent on deformation and orientation is employed to calculate the proton decay width through the deformed potential barrier. In addition, the spectroscopic factor is taken into account in the calculation, which is obtained in the relativistic mean field theory with NL3. The calculated results of semi-spherical nuclei are found to be in good agreement with the experimental data, and the results of well-deformed nuclei are also satisfactory. Moreover, a formula for the spherical proton emission half-life based on the Gamow quantum tunneling theory is presented.

Improved Results on Extraction of {sup 11}B(p, {alpha}{sub 0}){sup 8}Be and {sup 10}B(p, {alpha}){sup 7}Be S(E)-Factor Through the Trojan Horse Method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puglia, S. M. R.; Lamia, L.; Romano, S.

2010-08-12

In this work the analysis of the {sup 10}B(23p, {alpha}){sup 7}Be and {sup 11}B(p, {alpha}){sup 8}Be reactions, studied via the indirect Trojan Horse Method (THM), is discussed. In the astrophysical context of light nuclei LiBeB depletion, the above mentioned reactions are the main responsible for the destruction of boron in the stellar interior. The THM application allows their investigation in the astrophysically relevant energy region, around the Gamow Peak ({approx_equal}10 keV), overcoming the problems due to the presence of the Coulomb barrier and electron screening effect. The experimental procedure and the preliminary results are shown.

Direct measurement of nuclear cross sections of astrophysical relevance at LUNA: The 22Ne(p, γ) 23Na reaction

NASA Astrophysics Data System (ADS)

Ferraro, F.; LUNA Collaboration

2017-01-01

Most of the elements constituting the universe were produced in stars through a series of nuclear reactions. LUNA performs direct measurements of nuclear cross sections relevant to astrophysics, taking advantage of the low background at LNGS. The ^{22}Ne(p,γ)^{23}Na reaction rate, which belongs to the NeNa cycle of hydrogen burning, has been recently studied. Its rate is still very uncertain because of a lot of resonances lying inside the Gamow window. LUNA discovered three new resonances using two high-purity germanium detectors and considerably improved the existing upper limits on the lower energy resonances using a high-efficiency optically-segmented BGO crystal.

Neuronal and network computation in the brain

NASA Astrophysics Data System (ADS)

Babloyantz, A.

1999-03-01

The concepts and methods of non-linear dynamics have been a powerful tool for studying some gamow aspects of brain dynamics. In this paper we show how, from time series analysis of electroencepholograms in sick and healthy subjects, chaotic nature of brain activity could be unveiled. This finding gave rise to the concept of spatiotemporal cortical chaotic networks which in turn was the foundation for a simple brain-like device which is able to become attentive, perform pattern recognition and motion detection. A new method of time series analysis is also proposed which demonstrates for the first time the existence of neuronal code in interspike intervals of coclear cells.

State of the States

ERIC Educational Resources Information Center

Journal of Education Finance, 2017

2017-01-01

In 2016, a group of school finance scholars and public school practitioners gathered in Jacksonville, Florida, for the National Education Finance Academy's annual conference to discuss, among an array of topics, the state of P-20 finance in all 50 states. At the roundtable discussion, 36 states were represented, and scholars representing 30 states…

12 CFR 740.4 - Requirements for the official sign.

Code of Federal Regulations, 2011 CFR

2011-01-01

... participates in a shared branch network with other credit unions and accepts share deposits for members of.... No teller in a nonfederally insured credit union may display the official NCUA sign. (d) The Board...

12 CFR 740.4 - Requirements for the official sign.

Code of Federal Regulations, 2014 CFR

2014-01-01

... participates in a shared branch network with other credit unions and accepts share deposits for members of.... No teller in a nonfederally insured credit union may display the official NCUA sign. (d) The Board...

12 CFR 1005.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

..., code, or other means of access to a consumer's account, or any combination thereof, that may be used by..., automated teller machines (ATMs), and cash dispensing machines. (i) “Financial institution” means a bank...

12 CFR 1005.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

..., code, or other means of access to a consumer's account, or any combination thereof, that may be used by..., automated teller machines (ATMs), and cash dispensing machines. (i) “Financial institution” means a bank...