Vibronic couplings pseudo-Jahn-Teller coupling

Here we consider the case that the two excited electronic states <1> and belong to dipole-allowed representations, namely, one to A2 and the other to E, (Zgierski and Pawlikowski, 1979b). In the absence of pseudo-Jahn-Teller coupling between them, the corresponding vibronic wave-functions are of the form... 

There is good reason to believe that the pseudo Jahn-Teller effect commonly assumes an important role in a number of molecular processes including electronic relaxation. Large classes of heterocyclic molecules whose zero-order BO electronic states may be very close to one another are ideal candidates for these types of vibronic interaction.127 Should the lowest state 0X of a given multiplicity be strongly coupled to a nearby electronic state 02 the following spectral effects can be expected ... 

The general principles for the construction of the vibronic Hamiltonian and the symmetry selection rules are the same as indicated above and discussed in more detail in Chapter 7. The previous distinction between trigonal and tetragonal point groups does not play a role, and the first-order coupling is always accomplished by doubly degenerate (e) vibrational modes. In an analogous notation as in Eq. (3), the Hamiltonian for the linear (E + A) (g) e pseudo-Jahn-Teller effect is found to... 

VIBRONIC COUPLING IN INORGANIC SYSTEMS PHOTOCHEMISTRY, CONICAL INTERSECTIONS, AND THE JAHN-TELLER AND PSEUDO-JAHN-TELLER EFFECTS... 

Figure 69 Vibronic coupling for octahedral copper(II) (a) dynamic Jahn-Teller effect (alg and blg) (b) pseudo...

A parameterization method of the Hamiltonian for two electronic states which couple via nuclear distortions (vibronic coupling), based on density functional theory (DFT) and Slaters transition state method, is presented and applied to the pseudo-Jahn-Teller coupling problem in molecules with an s2-lone pair. The diagonal and off-diagonal energies of the 2X2 Hamiltonian matrix have been calculated as a function of the symmetry breaking angular distortion modes and r (Td)] of molecules with the coordination number CN = 3... 

Vibronic Coupling in Inorganic Systems Photochemistry, Conical Intersections, and the Jahn-Teller and Pseudo-Jahn-Teller Effects Russell G. Mckinlay, Justyna M. Zurek and Martin J. Paterson... 

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