ELECTRONIC ORBITAL DEGENERACY. I. COMBINED THEORY OF SPIN-ORBIT COUPLING AND JAHN-TELLER COUPLING

Abstract

It is well known that molecules in orbitally degenerate states, such as a ${^{2}}E$ electronic state, have two perturbing phenomena: spin-orbit coupling and Jahn-Teller coupling. The formet arises from the coupling of the unpaired electron's spin angular momentum with the electronic orbital angular momentum, while the latter is due to coupling between the electronic orbital motion and the vibrational motion of the atoms. When combined, these effects distort the vibronic energy levels of the molecule to patterns far from those obtained via the harmonic oscillator approximation. We have developed a computer program that includes both of these effects and calculates the vibronic levels of molecules in ${^{2}}E$ states. The program includes spin-orbit coupling and first- and second-order Jahn-Teller effects in any given number of vibrational modes.