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Ribeiro RF, Yuen-Zhou J. Continuous vibronic symmetries in Jahn-Teller models. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:333001. [PMID: 29845973 DOI: 10.1088/1361-648x/aac89e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Explorations of the consequences of the Jahn-Teller (JT) effect remain active in solid-state and chemical physics. In this topical review we revisit the class of JT models which exhibit continuous vibronic symmetries. A treatment of these systems is given in terms of their algebraic properties. In particular, the compact symmetric spaces corresponding to JT models carrying a vibronic Lie group action are identified, and their invariants used to reduce their adiabatic potential energy surfaces into orbit spaces of the corresponding Lie groups. Additionally, a general decomposition of the molecular motion into pseudorotational and radial components is given based on the behavior of the electronic adiabatic states under the corresponding motions. We also provide a simple proof that the electronic spectrum for the space of JT minimum-energy structures (trough) displays a universality predicted by the epikernel principle. This result is in turn used to prove the topological equivalence between bosonic (fermionic) JT troughs and real (quaternionic) projective spaces. The relevance of the class of systems studied here for the more common case of JT systems with only discrete point group symmetry, and for generic asymmetric molecular systems with conical intersections involving more than two states is likewise explored. Finally, we show that JT models with continuous symmetries present the simplest models of conical intersections among an arbitrary number of electronic state crossings, and outline how this information may be utilized to obtain additional insight into generic dynamics near conical intersections.
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Affiliation(s)
- Raphael F Ribeiro
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA 92093, United States of America
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Naghavi SS, Fabrizio M, Qin T, Tosatti E. Nanoscale orbital excitations and the infrared spectrum of a molecular Mott insulator: A15-Cs 3C 60. NANOSCALE 2016; 8:17483-17488. [PMID: 27714176 DOI: 10.1039/c6nr05725j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The quantum physics of ions and electrons behind low-energy spectra of strongly correlated molecular conductors, superconductors and Mott insulators is poorly known, yet fascinating especially in orbitally degenerate cases. The fulleride insulator Cs3C60 (A15), one such system, exhibits infrared (IR) spectra with low temperature peak features and splittings suggestive of static Jahn-Teller distortions with a breakdown of orbital symmetry in the molecular site. That is puzzling, since there is no detectable static distortion, and because the features and splittings disappear upon modest heating, which they should not. Taking advantage of the Mott-induced collapse of electronic wavefunctions from lattice-extended to nanoscale localized inside a caged molecular site, we show that the unbroken spin and orbital symmetry of the ion multiplets explains the IR spectrum without adjustable parameters. This demonstrates the importance of a fully quantum treatment of nuclear positions and orbital momenta in the Mott insulator sites, dynamically but not statically distorted. The observed demise of these features with temperature is explained by the thermal population of a multiplet term whose nuclear positions are essentially undistorted, but whose energy is very low-lying. That term is in fact a scaled-down orbital excitation analogous to that of other Mott insulators, with the same spin 1/2 as the ground state, but with a larger orbital momentum of two instead of one.
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Affiliation(s)
- S S Naghavi
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
| | - M Fabrizio
- International School for Advanced Studies (SISSA), and CNR-IOM Democritos National Simulation Center, Via Bonomea 265, I-34136 Trieste, Italy.
| | - T Qin
- International School for Advanced Studies (SISSA), and CNR-IOM Democritos National Simulation Center, Via Bonomea 265, I-34136 Trieste, Italy. and Institut für Theoretische Physik, Goethe-Universität, 60438 Frankfurt am Main, Germany
| | - E Tosatti
- International School for Advanced Studies (SISSA), and CNR-IOM Democritos National Simulation Center, Via Bonomea 265, I-34136 Trieste, Italy. and International Centre for Theoretical Physics (ICTP), Strada Costiera 11, I-34151 Trieste, Italy
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Iwahara N, Chibotaru LF. Orbital disproportionation of electronic density is a universal feature of alkali-doped fullerides. Nat Commun 2016; 7:13093. [PMID: 27713426 PMCID: PMC5059769 DOI: 10.1038/ncomms13093] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 09/01/2016] [Indexed: 11/09/2022] Open
Abstract
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. Understanding the electronic phases of alkali-doped fullerides is a long-standing and challenging task for material scientists. Here the authors show that Jahn-Teller instability and orbital disproportionation of electronic density in the lowest unoccupied molecular orbital band is universal in these systems.
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Affiliation(s)
- Naoya Iwahara
- Theory of Nanomaterials Group, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee, B-3001 Leuven, Belgium
| | - Liviu F Chibotaru
- Theory of Nanomaterials Group, Katholieke Universiteit Leuven, Celestijnenlaan 200F, Heverlee, B-3001 Leuven, Belgium
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Dunn JL, Alqannas HS, Lakin AJ. Jahn–Teller effects and surface interactions in multiply-charged fullerene anions and the effect on scanning tunneling microscopy images. Chem Phys 2015. [DOI: 10.1016/j.chemphys.2015.05.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Potočnik A, Ganin AY, Takabayashi Y, McDonald MT, Heinmaa I, Jeglič P, Stern R, Rosseinsky MJ, Prassides K, Arčon D. Jahn–Teller orbital glass state in the expanded fcc Cs3C60 fulleride. Chem Sci 2014. [DOI: 10.1039/c4sc00670d] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Magic-angle-spinning NMR measurements on fcc Cs3C60 to cryogenic temperatures reveal freezing-out of the C603¬ Jahn–Teller dynamics and emergence of an electronic orbital glass state guided by the C603¬ merohedral disorder.
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Affiliation(s)
- A. Potočnik
- Jožef Stefan Institute
- 1000 Ljubljana, Slovenia
| | - A. Y. Ganin
- Department of Chemistry
- University of Liverpool
- Liverpool L69 7ZD, UK
| | - Y. Takabayashi
- Department of Chemistry
- Durham University
- Durham DH1 3LE, UK
| | - M. T. McDonald
- Department of Chemistry
- Durham University
- Durham DH1 3LE, UK
| | - I. Heinmaa
- National Institute of Chemical Physics and Biophysics
- 12618 Tallinn, Estonia
| | - P. Jeglič
- Jožef Stefan Institute
- 1000 Ljubljana, Slovenia
- EN-FIST Centre of Excellence
- 1000 Ljubljana, Slovenia
| | - R. Stern
- National Institute of Chemical Physics and Biophysics
- 12618 Tallinn, Estonia
| | - M. J. Rosseinsky
- Department of Chemistry
- University of Liverpool
- Liverpool L69 7ZD, UK
| | - K. Prassides
- Department of Chemistry
- Durham University
- Durham DH1 3LE, UK
- WPI Research Center
- Advanced Institute for Materials Research
| | - D. Arčon
- Jožef Stefan Institute
- 1000 Ljubljana, Slovenia
- Faculty of Mathematics and Physics
- University of Ljubljana
- 1000 Ljubljana, Slovenia
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Iwahara N, Chibotaru LF. Dynamical Jahn-Teller effect and antiferromagnetism in Cs3C60. PHYSICAL REVIEW LETTERS 2013; 111:056401. [PMID: 23952422 DOI: 10.1103/physrevlett.111.056401] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 06/02/2023]
Abstract
The dynamical Jahn-Teller effect on fullerene sites in insulating Cs(3)C(60) is investigated fully ab initio. The vibronic excitations of rotational type are at ≥ 65 cm(-1), while the net kinetic contribution to the Jahn-Teller stabilization energy constitutes approximately 90 meV. This means that no localization of distortions by intermolecular interactions is possible in these fullerides; therefore, free rotations of deformations take place independently on each C(60). The latter destroy the orbital ordering and establish a conventional exchange interaction between S = 1/2 on fullerene sites. The corresponding exchange model is derived and predicts the Néel temperature for A15 Cs(3)C(60) close to experiment.
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Affiliation(s)
- Naoya Iwahara
- Division of Quantum and Physical Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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Klupp G, Matus P, Kamarás K, Ganin AY, McLennan A, Rosseinsky MJ, Takabayashi Y, McDonald MT, Prassides K. Dynamic Jahn-Teller effect in the parent insulating state of the molecular superconductor Cs₃C₆₀. Nat Commun 2012; 3:912. [PMID: 22713754 DOI: 10.1038/ncomms1910] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Accepted: 05/16/2012] [Indexed: 11/09/2022] Open
Abstract
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.
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Affiliation(s)
- Gyöngyi Klupp
- Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary
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Kato T. New method of accurate estimation of the electron–phonon coupling constants in fractionally charged incommensurate electronic states in molecular systems. J Chem Phys 2011; 135:024103. [DOI: 10.1063/1.3600066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Manini N, Dal Corso A, Fabrizio M, Tosatti E. Electron-vibration coupling constants in positively charged fullerene. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/13642810110062663] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Nicola Manini
- a Istituto Nazionale di Fisica della Materia, Unitá Trieste SISSA , 1-34013, Trieste , Italy
- b International School for Advanced Studies (SISSA) , Via Beirut 4, 1-34013, Trieste , Italy
| | - Andrea Dal Corso
- a Istituto Nazionale di Fisica della Materia, Unitá Trieste SISSA , 1-34013, Trieste , Italy
| | - Michele Fabrizio
- a Istituto Nazionale di Fisica della Materia, Unitá Trieste SISSA , 1-34013, Trieste , Italy
- b International School for Advanced Studies (SISSA) , Via Beirut 4, 1-34013, Trieste , Italy
- c International Centre for Theoretical Physics , PO Box 586, I-34014, Trieste , Italy
| | - Erio Tosatti
- a Istituto Nazionale di Fisica della Materia, Unitá Trieste SISSA , 1-34013, Trieste , Italy
- b International School for Advanced Studies (SISSA) , Via Beirut 4, 1-34013, Trieste , Italy
- c International Centre for Theoretical Physics , PO Box 586, I-34014, Trieste , Italy
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Abstract
The mechanism of the occurrence of intraatomic diamagnetic currents in the neutral He atoms with microscopic sizes is investigated. It is found that most of all electrons can form electron pairs originating from attractive Coulomb interactions between two electrons with opposite spins occupying the 1s atomic orbital in the neutral He atom at 298 K. Intraatomic diamagnetic currents in the neutral He atoms with microscopic sizes can be explained by such electron pairing. The transition temperature Tc(He),(1s) value at which intraatomic diamagnetic currents can disappear in each He atom is estimated. The Tc(He),(1s) values for the neutral He atoms with microscopic sizes are estimated to be much larger than the superconducting transition temperatures Tc,BCS values for the conventional superconductors with macroscopic sizes. This result can be understood from continuous energy levels of electronic states in conventional superconductivity with macroscopic sizes, and from discrete energy levels of electronic states in the neutral He atoms with microscopic sizes. The energy difference between the occupied and unoccupied orbitals decreases with an increase in material size and thus the second-order perturbation effect becomes more important with an increase in material size. Therefore, the mechanism of the occurrence of intraatomic diamagnetic current in the neutral He atoms suggested in this research would not be true for materials with large sizes. The dependence of electronic properties on temperature in the diamagnetic currents in the neutral He atoms with microscopic sizes is studied and compared with that in the conventional superconductivity with macroscopic sizes.
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Affiliation(s)
- Takashi Kato
- Institute for Innovative Science and Technology, Graduate School of Engineering, Nagasaki Institute of Applied Science, 3-1, Shuku-machi, Nagasaki 851-0121, Japan.
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Tomita S, Andersen JU, Cederquist H, Concina B, Echt O, Forster JS, Hansen K, Huber BA, Hvelplund P, Jensen J, Liu B, Manil B, Maunoury L, Brøndsted Nielsen S, Rangama J, Schmidt HT, Zettergren H. Lifetimes of C60(2-) and C70(2-) dianions in a storage ring. J Chem Phys 2007; 124:024310. [PMID: 16422586 DOI: 10.1063/1.2155435] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
C60(2-) and C70(2-) dianions have been produced by electrospray of the monoanions and subsequent electron pickup in a Na vapor cell. The dianions were stored in an electrostatic ring and their decay by electron emission was measured up to 1 s after injection. While C70(2-) ions are stable on this time scale, except for a small fraction of the ions which have been excited by gas collisions, most of the C60(2-) ions decay on a millisecond time scale, with a lifetime depending strongly on their internal temperature. The results can be modeled as decay by electron tunneling through a Coulomb barrier, mainly from thermally populated triplet states about 120 meV above a singlet ground state. At times longer than about 100 ms, the absorption of blackbody radiation plays an important role for the decay of initially cold ions. The tunneling rates obtained from the modeling, combined with WKB estimates of the barrier penetration, give a ground-state energy 200+/-30 meV above the energy of the monoanion plus a free electron and a ground-state lifetime of the order of 20 s.
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Affiliation(s)
- S Tomita
- Department of Physics and Astronomy, University of Aarhus, Aarhus C DK-8000, Denmark
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14
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Chibotaru L. Spin–vibronic superexchange and dynamical vibronic order in ammoniated cubic fullerides. J Mol Struct 2007. [DOI: 10.1016/j.molstruc.2006.12.064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Kato T, Yamabe T. Strong vibronic interactions and possible electron pairing in the photoinduced excited electronic states in nanosized molecules. J Mol Struct 2007. [DOI: 10.1016/j.molstruc.2007.01.028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Ceulemans A, Lijnen E, Qiu QC. Jahn and Tellers last case: the icosahedral sextet, gamma(9) x (g+2 h). Chemphyschem 2007; 8:64-7. [PMID: 17146811 DOI: 10.1002/cphc.200600566] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Arnout Ceulemans
- Department of Chemistry and INPAC Institute for Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium.
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Ceulemans A, Lijnen E. The Jahn–Teller Effect in Chemistry. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2007. [DOI: 10.1246/bcsj.80.1229] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Garcia-Fernandez P, Bersuker IB, Boggs JE. Orbital disproportionation and spin crossover as a pseudo Jahn-Teller effect. J Chem Phys 2006; 125:104102. [PMID: 16999510 DOI: 10.1063/1.2346682] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
It is shown that in systems with electronic half-closed-shell configurations of degenerate orbitals, e(2) and t(3) (which have totally symmetric charge distribution), ground state distortions from high-symmetry geometries may occur due to a strong pseudo Jahn-Teller effect (PJTE) in the excited states, resulting also in a novel phenomenon of PJT-induced spin crossover. There is no JTE neither in the ground state term nor in the excited terms (including degenerate terms) of these configurations but a strong PJT mixing between two excited states [((1)E+(1)A) [cross-filled circle] e and ((2)T(1)+(2)T(2)) [cross-filled circle] e in the e(2) and t(3) cases, respectively] pushes down the lower term to cross the ground state of the undistorted system and to form the global minimum with a distorted geometry. The analysis of the electronic structure of this distorted configuration shows that it is accompanied by orbital disproportionation: instead of proportional population of all degenerate orbitals by one electron each (as in the ground state of the undistorted system that follows Hund's rule), two electrons with opposite spins occupy one orbital, resulting in transformations of the type (e(theta);e(epsilon))-->(e(theta)e(theta)) for e(2) and (t(x);t(y);t(z))-->(t(x);t(x);t(z)) for t(3) systems. Since the two geometry configurations, undistorted and distorted, appertain to different electronic terms that have different spin states, the formation of the global minimum with the distorted configuration is accompanied by a spin crossover. Distinguished from the known spin-crossover phenomenon in some transition metal compounds, the two states with different spin in the PJT-induced spin crossover have also different nuclear configurations, undistorted and distorted, that coexist with a relatively small energy difference. The change of configuration reduces significantly the rate of relaxation between the two states; the relaxation is further reduced by the lower spin-orbital coupling in the light-atom systems as compared with transition metal compounds. This means that there may be systems for which the switch between the two states (in both directions) under perturbations may be observed as a single-molecule phenomenon. Systems with half-closed-shell electronic configurations e(2) and t(3) are available in a variety of molecules from different classes, organic and inorganic; the theory is illustrated here by ab initio calculations for a series of molecular systems, including Si(3), Si(3)C, CuF(3), Na(3), Si(4), Na(4), Na(4) (-), and C(60) (3-), which are in agreement with the experimental data available.
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Affiliation(s)
- P Garcia-Fernandez
- Institute for Theoretical Chemistry, Chemistry and Biochemistry Department, The University of Texas at Austin, Austin, TX 78712-0165, USA.
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Kato T, Yamabe T. Electron-phonon interactions in the monocations of polyacetylenes. J Chem Phys 2006; 124:084705. [PMID: 16512734 DOI: 10.1063/1.2149851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Electron-phonon interactions in the monocations of trans-polyacetylenes such as C2H4 (2tpa), C4H6 (2tpa), C6H8 (6tpa), and C8H10 (8tpa) are studied. The C-C stretching Ag modes around 1700 cm(-1) afford the largest electron-phonon coupling constants in the monocations of polyacetylenes. However, the C-C bending Ag modes around 1200 cm(-1) afford much smaller electron-phonon coupling constants than the C-C stretching Ag modes around 1700 cm(-1) in the monocations of polyacetylenes. The total electron-phonon coupling constants for the monocations (l HOMO) are estimated to be 0.357, 0.285, 0.281, and 0.279 eV for 2tpa, 4tpa, 6tpa, and 8tpa, respectively. The l HOMO values for polyacetylenes with C 2h geometry hardly change with an increase in molecular size while those for polyacenes with D 2h geometry significantly decrease with an increase in molecular size. The l HOMO values for polyacetylenes are larger than those for polyacenes. The calculated results are rationalized in terms of the phase patterns of the molecular orbitals in detail. The electron transfer in the positively charged polyacetylenes is also discussed. Intramolecular electron mobility (sigma(intra,monocation)) in the positively charged polyacetylenes is estimated to be smaller than those for the positively charged polyacenes. The reorganization energies for the positively charged polyacetylenes are estimated to be larger than those for the positively charged polyacenes. Thus, the larger overlap integrals between two neighboring molecules are needed for the positively charged polyacetylenes to become good conductor than those for positively charged polyacenes. On the other hand, the conditions under which the electron-electron interactions are attractive are more easily realized in the monocations of polyacetylenes than in the monocations of polyacenes. The quality as conducting materials would not significantly depend on the molecular size in the positively charged polyacetylenes, compared with that in the positively charged polyacenes. Multimode problem is also treated in order to investigate how consideration of multimode problem is closely related to the characteristics of the electron-phonon interactions.
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Affiliation(s)
- Takashi Kato
- Institute for Innovative Science and Technology, Graduate School of Engineering, Nagasaki Institute of Applied Science, 3-14 Shuku-machi, Nagasaki 851-0121, Japan.
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Kato T, Yamabe T. Vibronic interactions and possible electron pairing in positively charged cyanodienes. J Chem Phys 2005; 123:94701. [PMID: 16164356 DOI: 10.1063/1.1993553] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The conditions under which the attractive electron-electron interactions are realized in the monocations of sigma-conjugated cyanodienes such as C(6)N(4)H(4), C(8)N(6)H(4), and C(10)N(8)H(4) and of pi-conjugated acenes are discussed. The total electron-phonon coupling constants for the monocations l(HOMO) of cyanodienes are much larger than those for the monocations of acenes. The strong sigma orbital interactions between two neighboring atoms in the highest occupied molecular orbitals (HOMO) of sigma-conjugated cyanodienes are the main reason for the calculated results. Furthermore, we discuss how the conditions under which the monocation crystals become good conductor are related to the molecular size. Both the l(HOMO) values and the reorganization energies between the neutral molecules and the monocations decrease with an increase in molecular size in cyanodienes. The calculated results for the sigma-conjugated cyanodienes are compared with those for the pi-conjugated acenes in order to investigate how the CH-N substitutions in cyanodienes are closely related to the l(HOMO) values and the reorganization energies. Both the l(HOMO) and the reorganization energies in the positively charged sigma-conjugated cyanodienes are much larger than those in the positively charged pi-conjugated acenes. This means that in order to become good conductors, the positively charged sigma-conjugated cyanodienes need larger overlap integral between two adjacent molecules than the positively charged pi-conjugated acenes. On the other hand, since the l(HOMO) values for cyanodienes are much larger than those for acenes, the condition of attractive electron-electron interactions is more easily to be realized in the monocations of cyanodienes than in the monocations of acenes. It is suggested that the positively charged sigma-conjugated cyanodienes cannot easily become good conductors, but the conditions under which the electron-electron interactions become attractive are realized more easily in the positively charged sigma-conjugated cyanodienes than in the positively charged pi-conjugated acenes.
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Affiliation(s)
- Takashi Kato
- Institute for Innovative Science and Technology, Graduate School of Engineering, Nagasaki Institute of Applied Science, 3-1, Shuku-machi, Nagasaki 851-0121, Japan.
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Kato T, Yamabe T. Electron-phonon interactions in photoinduced excited electronic states in fluoroacenes. J Chem Phys 2005; 123:24301. [PMID: 16050739 DOI: 10.1063/1.1950670] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The electron-phonon coupling constants [l(B1u(HOMO-->LUMO))] in the photoinduced excited electronic states in fluoroacenes are estimated and compared with those in the monoanions (l(LUMO)) and cations (l(HOMO)). The l(B1u(HOMO-->LUMO)) values are much larger than the l(LUMO) and l(HOMO) values in fluoroacenes. Furthermore, the Coulomb pseudopotential mu* values for the excited electronic states are estimated to be smaller than those for the monoanions and cations. The complete phase patterns difference between the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) is the main reason why the electron-phonon coupling constants and the mu* values are larger and smaller, respectively, in the photoinduced excited electronic states than in the monoanions and cations. The possible electron pairing and Bose-Einstein condensation in the excited electronic states of fluoroacenes are discussed. Because of larger electron-phonon coupling constants and smaller mu* values in the excited electronic states than in the charged states, the conditions under which the electron-electron interactions become attractive can be more easily realized, in principle, in the excited electronic states than in the charged states in fluoroacenes. The l(B1u(HOMO-->LUMO)) values hardly change by H-F substitution, even though the l(LUMO) and l(HOMO) values significantly increase by H-F substitution in acenes. Antibonding interactions between carbon and fluorine atoms in the HOMO and LUMO are the main reason why the l(B1u(HOMO-->LUMO)) values hardly change by H-F substitution in acenes.
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Affiliation(s)
- Takashi Kato
- Institute for Innovative Science and Technology, Graduate School of Engineering, Nagasaki Institute of Applied Science, 3-1, Shuku-machi, Nagasaki 851-0121, Japan.
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Chibotaru LF. Spin-vibronic superexchange in Mott-Hubbard fullerides. PHYSICAL REVIEW LETTERS 2005; 94:186405. [PMID: 15904389 DOI: 10.1103/physrevlett.94.186405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Indexed: 05/02/2023]
Abstract
In the Mott-Hubbard cubic fulleride Li3(NH3)6C60 the superexchange energy is found to be much smaller than the rotational quantum for Jahn-Teller deformations at fullerene sites. This gives rise to a new type of superexchange interaction involving threefold degenerate vibronic ground states of C3-60 ions. In contrast with spin-orbital models, the spin-vibronic superexchange can be only antiferromagnetic and shows a significant vibronic reduction of the superexchange amplitude, in agreement with magnetic susceptibility data. As a function of the transfer parameters, two quadrupolar fully dynamical vibronic orders with quenched vibronic moments on sites develop in the ground state.
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Affiliation(s)
- L F Chibotaru
- Department of Chemistry, University of Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium
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24
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Tomita S, Andersen JU, Bonderup E, Hvelplund P, Liu B, Nielsen SB, Pedersen UV, Rangama J, Hansen K, Echt O. Dynamic Jahn-Teller effects in isolated C60- studied by near-infrared spectroscopy in a storage ring. PHYSICAL REVIEW LETTERS 2005; 94:053002. [PMID: 15783634 DOI: 10.1103/physrevlett.94.053002] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Indexed: 05/24/2023]
Abstract
We have measured the near-infrared absorption spectrum for isolated C60- ions at room temperature. Two bands, at 9145 cm(-1) and 10460 cm(-1), have been identified in addition to the main absorption band at 9382 cm(-1), seen also at low temperature in a matrix. An interpretation based on the theory of dynamic Jahn-Teller effects is proposed.
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Affiliation(s)
- S Tomita
- Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C, Denmark
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25
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Kato T, Yamabe T. The effect of atomic substitution on electron–phonon interactions in negatively charged B, N-substituted acenes. J Chem Phys 2004; 121:501-9. [PMID: 15260571 DOI: 10.1063/1.1755671] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Electron-phonon interactions in the monoanions of B, N-substituted acenes such as B(3)N(3)F(6) (1f) and B(5)N(5)F(8) (2f) are studied, and compared with those in the monoanions of B(3)N(3)H(6) (1h) and B(5)N(5)H(8) (2h), and B(3)N(3)D(6) (1d) and B(5)N(5)D(8) (2d). The low frequency modes around 500 cm(-1) as well as the frequency modes higher than 1000 cm(-1) strongly couple to the lowest unoccupied molecular orbitals (LUMO) in 1f and 2f. The total electron-phonon coupling constants (l(LUMO)) are estimated to be 2.710 and 2.054 eV for 1f and 2f, respectively, and those are estimated to be 0.342 and 0.235 eV for 1d and 2d, respectively, while those were estimated to be 0.340 and 0.237 eV for 1h and 2h, respectively. That is, the l(LUMO) value increases much more significantly by H-F substitution than by H-D substitution in B, N-substituted acenes. The larger displacements of B and N atoms in the vibronic active modes in 1f and 2f than those in 1d and 2d due to larger atomic mass of fluorine than that of deuterium, and the phase patterns difference between the LUMO in 1f and 2f, in which the atomic orbitals between N and its neighboring F atoms form strong sigma-antibonding interactions, and that in 1d and 2d, in which the atomic orbitals between two neighboring B and N atoms form weak pi-bonding and pi-antibonding interactions, are the main reason why the l(LUMO) value increases much more significantly by H-F substitution than by H-D substitution. The reorganization energies between the neutral molecules and the corresponding monoanions are estimated to be 0.122, 0.063, 0.733, and 0.830 eV for 1h, 2h, 1f, and 2f, respectively. Therefore, the estimated reorganization energies between the neutral molecules and the corresponding monoanions for 1f and 2f are much larger than those for 1h and 2h.
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Affiliation(s)
- Takashi Kato
- Fukui Institute for Fundamental Chemistry, Kyoto University, 34-4 Takano-Nishihiraki-cho, Sakyo-ku, Kyoto 606-8103, Japan.
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Han JE, Gunnarsson O, Crespi VH. Strong superconductivity with local Jahn-Teller phonons in C60 solids. PHYSICAL REVIEW LETTERS 2003; 90:167006. [PMID: 12731998 DOI: 10.1103/physrevlett.90.167006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2002] [Indexed: 05/24/2023]
Abstract
We analyze fulleride superconductivity at experimental doping levels, treating the electron-electron and electron-phonon interactions on an equal footing, and demonstrate that the Jahn-Teller phonons create a local (intramolecular) pairing which is surprisingly resistant to the Coulomb repulsion, despite the weakness of retardation in these low-bandwidth systems. The requirement for coherence throughout the solid then yields a very strong doping dependence to T(c), one consistent with experiment and much stronger than expected from standard Eliashberg theory.
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Affiliation(s)
- J E Han
- Department of Physics, The Pennsylvania State University, University Park, Pennsylvania 16802-6300, USA
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27
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Kato T, Hirao K. Vibronic Interactions and Jahn–Teller Effects in Charged Hydrocarbons. ADVANCES IN QUANTUM CHEMISTRY 2003. [DOI: 10.1016/s0065-3276(03)44016-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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28
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Lüders M, Manini N. Jahn–Teller Distortions and Excitation Energies in. ADVANCES IN QUANTUM CHEMISTRY 2003. [DOI: 10.1016/s0065-3276(03)44018-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Sookhun S, Bates C, Dunn J, Diery W. Multiple Occupancy of Triply Degenerate States in Icosahedral Symmetry. ADVANCES IN QUANTUM CHEMISTRY 2003. [DOI: 10.1016/s0065-3276(03)44021-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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30
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Electron Correlation and Jahn–Teller Effect in Alkali-Metal-Doped C60. ADVANCES IN QUANTUM CHEMISTRY 2003. [DOI: 10.1016/s0065-3276(03)44035-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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31
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Nikolaev AV, Michel KH. Molecular terms, magnetic moments, and optical transitions of molecular ions C60m±. J Chem Phys 2002. [DOI: 10.1063/1.1497644] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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32
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Kato T, Yamabe T. Vibronic interactions and superconductivity in acene anions and cations. J Chem Phys 2001. [DOI: 10.1063/1.1409539] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Bersuker IB. Modern aspects of the Jahn-Teller effect theory and applications to molecular problems. Chem Rev 2001; 101:1067-114. [PMID: 11709858 DOI: 10.1021/cr0004411] [Citation(s) in RCA: 424] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- I B Bersuker
- Institute for Theoretical Chemistry, Department of Chemistry & Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.
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34
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Affiliation(s)
- C A Reed
- Department of Chemistry, University of California-Riverside, Riverside, California 92521-0403
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35
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Qiu QC, Liu YM, Bates CA, Dunn JL. First-order Reduction Factors for the T1u ࣹ hg Jahn-Teller System*. Z PHYS CHEM 1997. [DOI: 10.1524/zpch.1997.200.part_1_2.103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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36
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Tosatti E, Manini N, Gunnarsson O. Surprises in the orbital magnetic moment and g factor of the dynamic Jahn-Teller ion C60-. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:17184-17190. [PMID: 9985854 DOI: 10.1103/physrevb.54.17184] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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38
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Gunnarsson O, Koch E, Martin RM. Mott transition in degenerate Hubbard models: Application to doped fullerenes. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:R11026-R11029. [PMID: 9984977 DOI: 10.1103/physrevb.54.r11026] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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39
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Ceulemans A, Chibotaru LF. Isostationary functions for multimode and multilevel Jahn-Teller systems. ACTA ACUST UNITED AC 1996. [DOI: 10.1007/bf00186442] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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40
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Manini N, Tosatti E. Dynamical Jahn-Teller effect and Berry phase in positively charged fullerenes: Basic considerations. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:7157-7167. [PMID: 9984337 DOI: 10.1103/physrevb.54.7157] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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41
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Alexandrov AS, Kabanov VV. Theory of superconducting Tc of doped fullerenes. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 54:3655-3661. [PMID: 9986274 DOI: 10.1103/physrevb.54.3655] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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42
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Borshch SA, Prassides K. Fullerene Anions: Jahn−Teller or Pseudo-Jahn−Teller Effects? ACTA ACUST UNITED AC 1996. [DOI: 10.1021/jp960015c] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- S. A. Borshch
- Institut de Recherches sur la Catalyse, UPR 5401 CNRS, 2, avenue Albert Einstein, 69626 Villeurbanne Cedex, France, and Ecole Normale Supérieure de Lyon, Laboratoire de Chimie Théorique, 46, allée d'Italie, 69364 Lyon Cedex 07, France
| | - K. Prassides
- School of Chemistry and Molecular Sciences, University of Sussex, Falmer, Brighton BN1 9QJ, United Kingdom
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González J, Alvarez JV. Variational approach to the Hubbard model in a C60 cluster. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:11729-11733. [PMID: 9982797 DOI: 10.1103/physrevb.53.11729] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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44
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Fabrizio M, Airoldi M, Tosatti E. Interplay of orbital degeneracy and superconductivity in a molecular conductor. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:12086-12093. [PMID: 9982836 DOI: 10.1103/physrevb.53.12086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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45
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O'Brien MC. Vibronic energies in C60 n- and the Jahn-Teller effect. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:3775-3789. [PMID: 9983928 DOI: 10.1103/physrevb.53.3775] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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46
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Ceulemans A, Chibotaru LF. Icosahedral T1u+T1g Jahn-Teller problem. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:2460-2462. [PMID: 9983748 DOI: 10.1103/physrevb.53.2460] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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47
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Winter J, Kuzmany H. Landau damping and lifting of vibrational degeneracy in metallic potassium fulleride. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:655-661. [PMID: 9983016 DOI: 10.1103/physrevb.53.655] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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48
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Qiu QC, Liu YM, Bates CA, Dunn JL. First-order Reduction Factors for the T 1u⊗ h gJahn-Teller System*. Z PHYS CHEM 1996. [DOI: 10.1524/zpch.1996.1.1.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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49
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Santoro G, Manini N, Parola A, Tosatti E. Phase diagram of a model of correlated hopping of electrons in a lattice of Berry molecules. PHYSICAL REVIEW. B, CONDENSED MATTER 1996; 53:828-836. [PMID: 9983039 DOI: 10.1103/physrevb.53.828] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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50
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Pietronero L, Strässler S, Grimaldi C. Nonadiabatic superconductivity. I. Vertex corrections for the electron-phonon interactions. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:10516-10529. [PMID: 9980106 DOI: 10.1103/physrevb.52.10516] [Citation(s) in RCA: 150] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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