The Jahn–Teller and pseudo-Jahn–Teller effects in the low-lying electronic states of 1,3,5-trifluorobenzene radical cation

2009 ◽  
Vol 11 (46) ◽  
pp. 10867 ◽  
Author(s):  
T. Mondal ◽  
S. Mahapatra
Keyword(s):  
Radical Cation ◽  
Electronic States ◽  
Jahn Teller

Theoretical assignments of the electronic states of the π-radical cation of ethylene

1977 ◽  
Vol 45 (1) ◽  
pp. 50-54 ◽  
Author(s):  
W.R. Rodwell ◽  
M.F. Guest ◽  
D.T. Clark ◽  
D. Shuttleworth
Keyword(s):  
Radical Cation ◽  
Electronic States

A Jahn–Teller analysis of K3 and Rb3 in the electronic states 12E′ and 12E″

2010 ◽  
Vol 375 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Andreas W. Hauser ◽  
Carlo Callegari ◽  
Pavel Soldán ◽  
Wolfgang E. Ernst
Keyword(s):  
Electronic States ◽  
Jahn Teller

Cooperative Pseudo Jahn-Teller Effect as Microscopic Mechanism of (OMT)-(LTT) Structural Phase Transition in La2−xBaxCuO4Superconductors

1992 ◽  
Vol 291 ◽  
Author(s):  
Michael D. Kaplan
Keyword(s):  
Phase Transition ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Electronic States ◽  
Teller Effect ◽  
Excited Electronic States ◽  
Microscopic Mechanism ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Local Distortions

ABSTRACTA microscopic mechanism for the structural phase transition from the orthorhombic mediate temperature (OMT) phase into the low temperature tetragonal (LTT) one is suggested on the basis of the cooperative pseudo Jahn-Teller effect. The local distortions mixing the ground and the first excited electronic states are ordered antiferrodistortively and are connected in part, with the oxygen octahedra rotations around the [100] axis. The results are in agreement, with the neutron scattering experiments data.

Studies of the Jahn-Teller effect. I. A survey of the static problem

1957 ◽  
Vol 238 (1215) ◽  
pp. 425-447 ◽  
Keyword(s):  
Electronic States ◽  
Static Problem ◽  
Electronic Energy ◽  
Tetragonal Symmetry ◽  
Linear Molecule ◽  
Subsequent Paper ◽  
Jahn Teller ◽  
Near Degeneracy ◽  
Static Distortion ◽  
Physical Features

According to the Jahn-Teller theorem, symmetrical molecules with degenerate electronic states are unstable. Such molecules therefore take up a distorted shape. If there is near-degeneracy, the symmetrical shape may also be unstable. We have studied the distortion in some particular cases. The approach is to minimize the total electronic energy with respect to distortions of the nuclear framework, the latter being considered to be static. There are always several equivalent distortions of equal energy, so that a static distortion fails to remove the degeneracy. The discussion of dynamic effects is postponed to a subsequent paper. A linear molecule of formula BAB , for which two electronic states of opposite symmetry are sufficiently nearly degenerate, will be stable in a configuration with unequal A—B separations, and unstable when symmetrical. This example illustrates some of the main physical features of Jahn-Teller distortions in a simple manner. Although we know of no example where the symmetrical structure is actually unstable, there are examples where the tendency towards distortion noticeably reduces the force constant of the asymmetric vibration. Octahedral complexes AB 6 with degenerate electronic states occur in many situations (e. g. paramagnetic crystals, F-centres, luminescent centres and exciton states in cubic crystals). The orbital degeneracy may be threefold ( T 1 and T 2 ) or twofold. In the former case the stable distortion is found to be either of tetragonal symmetry about a [100] direction, or of trigonal symmetry about a [111] direction. The twofold degenerate situation leads to a more complicated situation. If one neglects anharmonic effects there appears to be an infinity of distortions minimizing the energy; a more detailed consideration of the anharmonic terms shows that the stable distortions are of elongated tetragonal character. This result has an important bearing on complexes involving the cupric ion.

scholarly journals The Jahn–Teller effect in the presence of partial isotopic substitution: the B̃1E′′ state of NH2D and NHD2

2015 ◽  
Vol 17 (21) ◽  
pp. 14145-14158 ◽  
Author(s):  
Ashim Kumar Saha ◽  
Gautam Sarma ◽  
Chung-Hsin Yang ◽  
Sebastiaan Y. T. van de Meerakker ◽  
David H. Parker ◽  
...  
Keyword(s):  
Force Field ◽  
Field Model ◽  
Electronic States ◽  
Teller Effect ◽  
Isotopic Substitution ◽  
Quadratic Force Field ◽  
Jahn Teller ◽  
Jahn Teller Effect

A simple linear and quadratic force field model for the lifting of the degeneracy on asymmetric isotopic substitution in degenerate electronic states subject to a weak Jahn–Teller effect.

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