ChemInform Abstract: A Trimer Vibronic Coupling Model for Triptycene: The Jahn-Teller and Barnett Effects.

ChemInform ◽  
2010 ◽  
Vol 24 (33) ◽  
pp. no-no
Author(s):  
M. J. RILEY ◽  
A. FURLAN ◽  
H. U. GUEDEL ◽  
S. LEUTWYLER
Keyword(s):  
Coupling Model ◽  
Vibronic Coupling ◽  
Jahn Teller

An alternative model of the vibronic coupling in octahedral complexes

1988 ◽  
Vol 53 (6) ◽  
pp. 1134-1140
Author(s):  
Martin Breza ◽  
Peter Pelikán
Keyword(s):  
Linear Regression ◽  
Alternative Model ◽  
Potential Surface ◽  
Analytical Formula ◽  
Coupling Model ◽  
Regression Method ◽  
Vibronic Coupling ◽  
Linear Regression Method ◽  
Active Systems ◽  
Jahn Teller

It is suggested that for some transition metal hexahalo complexes, the Eg-(a1g + eg) vibronic coupling model is better suited than the classical T2g-(a1g + eg) model. For the former, alternative model, the potential constants in the analytical formula are evaluated from the numerical map of the adiabatic potential surface by using the linear regression method. The numerical values for 29 hexahalo complexes of the 1st row transition metals are obtained by the CNDO/2 method. Some interesting trends of parameters of such Jahn-Teller-active systems are disclosed.

scholarly journals A trimer vibronic coupling model for triptycene: The Jahn–Teller and Barnett effects

1993 ◽  
Vol 98 (5) ◽  
pp. 3803-3815 ◽  
Author(s):  
Mark J. Riley ◽  
Alan Furlan ◽  
Hans U. Güdel ◽  
Samuel Leutwyler
Keyword(s):  
Coupling Model ◽  
Vibronic Coupling ◽  
Jahn Teller

Strong Pseudo Jahn–Teller Effect on the Single Hexagonal Unit of Germanene

MRS Advances ◽  
2016 ◽  
Vol 1 (22) ◽  
pp. 1591-1596 ◽  
Author(s):  
J. R. Soto ◽  
B. Molina ◽  
J. J. Castro
Keyword(s):  
Dft Calculations ◽  
Excited States ◽  
Density Functional ◽  
Coupling Model ◽  
Vibronic Coupling ◽  
Coupling Constants ◽  
Hybrid Functional ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Different Origins

ABSTRACTGermanene, the 2D graphene-like Ge nanosheet, has been recently the subject of many theoretical studies and experimental attempts to synthesize it on Ag(111), Au(111) and Pt(111) surfaces. The experimental and theoretical evidences of germanene show a 2D continuous honeycomb layer with a buckled conformation. Density functional theory (DFT) calculations have predicted a larger buckling for germanene than silicene whose origin is also associated with a pseudo Jahn–Teller (PJT) effect. In this work we show that despite the fact that both, silicene and germanene possess a buckled conformation with a PJT origin, their vibronic coupling have different origins. The analysis is based on the PJT puckering instability of the hexagermabenzene molecule, the single hexagonal unit of germanene. This is done through the linear vibronic coupling model between the ground and the lowest excited states, which leads to a puckering distortion of the more symmetric cluster. We study both, the multilevel superposition vibronic model and possible mixing of excited states of different irreducible representations, which have been used to show the origin of similar structural transitions in hexagonal silicon and gold ring systems respectively. We show that contrary to other cases with one six-member rings, for the hexagermabenzene molecule a mixture of both the multilevel PJT and a ground state coupling with two quasi-degenerate excited states is necessary for a satisfactory explanation of puckering. Our model allows a determination of the coupling constants and predicts simultaneously the Adiabatic Potential Energy Surface (APES) behavior for the ground and excited states around the maximum symmetry point. The analysis is based on a scalar relativistic DFT and time-dependent DFT (TD-DFT) calculations in the Zero Order Regular Approximation (ZORA) using the B3LYP hybrid functional.

Studies of the Jahn - Teller effect IV. The vibrational spectra of spin-degenerate molecules

1962 ◽  
Vol 255 (1050) ◽  
pp. 31-53 ◽  
Keyword(s):  
Raman Spectrum ◽  
Raman Spectra ◽  
Vibrational Spectra ◽  
Physical Theory ◽  
Vibronic Coupling ◽  
Infra Red ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Active Vibration ◽  
Degenerate States

The physical theory necessary for interpreting the vibrational spectra of spin-degenerate molecules is developed in this paper. Particular attention is paid to those molecules whose behaviour is expected to be markedly different from that of both orbitally non-degenerate molecules and those with purely spatial degeneracy. These include certain Kramers degenerate molecules, whose Raman spectra are expected to contain reverse-polarized contributions, and also tetrahedral and octahedral molecules in fourfold degenerate states. The case of a fourfold degenerate octahedral molecule is investigated in the limits of strong vibronic coupling by one of the Jahn—Teller active vibrations (e g and t 2g ). It turns out that the forbidden t 2u vibration may be infra-red active, that the Raman spectrum may contain reverse-polarized contributions and that both infra-red and Raman spectra may contain strong progressions of bands involving multiple excitations of the vibronically active vibration.

Jahn-Teller effect in Rydberg series: a multi-state vibronic coupling problem

1990 ◽  
Vol 16 (1) ◽  
pp. 49-60 ◽  
Author(s):  
A. Staib ◽  
W. Domcke ◽  
A. L. Sobolewski
Keyword(s):  
Vibronic Coupling ◽  
Teller Effect ◽  
Rydberg Series ◽  
Coupling Problem ◽  
Jahn Teller ◽  
Jahn Teller Effect
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