Absorption spectra of dimer negative ions

Abstract

The absorption spectra of dimer negative ions have been studied as a function of vibronic (‘‘electron-phonon’’) coupling strength and electron tunneling (‘‘transfer integral’’) parameter. A model Hamiltonian for the dimer system has been taken from that of Fulton and Gouterman and the eigenvalue equation has been solved by the Merrifield method. As the vibronic coupling strength is increased for a fixed value of tunneling parameter, the physical meaning of the absorption spectrum changes from that of an electronic resonance transition to that of a vibronic electron transfer transition.