Effective-hamiltonian approach to Jahn-Teller coupling of impurities in crystals

Abstract

The problem of an impurity ion subject to linear Jahn-Teller coupling with vibrational modes of the crystal is reconsidered. A trial ground-state wavefunction is postulated in which one linear combination of vibrational modes behaves as though subject to a molecular Jahn-Teller effect while the rest are decoupled from the electronic states. The linear combination is selected by a variation of the ground-state energy of the system.