Dynamics and thermodynamics of the molecular polaron

Abstract

The static and dynamical properties of the molecular (two sites) polaron are investigated. The problem is reduced to that of a succession of electron hops in imaginary time, interacting with each other by phonon exchange. It can be solved analytically in the two regimes h(cross) omega ₀/kT>>1 (self trapped) and h(cross) omega ₀/kT<0 is the phonon frequency. There is a crossover between the two regimes which can be evaluated for a band of phonons where it is found to be smooth. The phonons have two effects on the motion of the electron: they reduce the hopping frequency and act also as a frequency modulation. The dynamical polarisability has a spectrum which is broadened by the frequency modulation. It is this fact which enables the molecular polaron (or any similar binary system) to be used at the emitting or receiving end of a communication channel.