E–e Jahn–Teller system: Calculations of the low-lying energy levels

Abstract

A localized dynamical Jahn–Teller (E–e) system is considered. The energy eigenvalues of the zero‐, one‐, and two‐phonon states are calculated by means of the combination of a nonlinear exponential transformation and a Ritz variational procedure. They are given for the whole coupling region. In the strong coupling region the ground state is compared with the results of another transformation, that tends to be exact in that region. It turns out that the chosen procedure is exact in both extremal coupling regions and very accurate in the intermediate region.