Inelastic scattering in a local polaron model with quadratic coupling to bosons

TL;DR

This paper calculates inelastic scattering probabilities in a local polaron model with quadratic boson coupling, revealing higher probabilities for multi-boson processes and applying the theory to surface vibrational excitations using DFT.

Contribution

It provides an exact algebraic calculation of inelastic scattering in a quadratic coupling polaron model and applies it to surface vibrational energy transfer.

Findings

Quadratic coupling increases inelastic scattering probabilities involving many bosons.

Application to CO on Cu(100) shows different vibrational mode excitation probabilities.

The algebraic approach enables exact calculation of two-particle Green functions.

Abstract

We calculate the inelastic scattering probabilities in the wide band limit of a local polaron model with quadratic coupling to bosons. The central object is a two-particle Green function which is calculated exactly using a purely algebraic approach. Compared with the usual linear interaction term a quadratic interaction term gives higher probabilities for inelastic scattering involving a large number of bosons. As an application we consider the problem hot electron mediated energy transfer at surfaces and use the delta self-consistent field extension of density functional theory to calculate and compare coupling parameters and probabilities for exciting different vibrational modes of CO adsorbed on a Cu(100) surface.