COMMENTS ON EXCITON-PHONON COUPLING .2. VARIATIONAL SOLUTIONS

Two variational calculations of the energy and correlation functions for a simple excition-phonon coupled system are presented and contrasted to the adiabatic solution and the exact solution. The simpler variational solution leads to two minima and abrupt changes in the properties of the system; an asymmetric variational wavefunction, motivated by the form of perturbation theory for this problem, leads to smooth behavior in agreement with the exact result. © 1979.