Tailoring model Hamiltonians for dihalogen—rare gas matrix problems

Abstract

A strategy for reducing the number of electronic states which need to be incorporated into a diatomics-in-molecules description of prototypical condensed phase processes is demonstrated. The selection of a problem-adapted representation is based on symmetry properties of the molecular basis set and its disturbance by the external potential due to the environment. Using the \({B \leftarrow X}\) excitation of Br2 in solid Argon as an example, we show that the energy range accessible via a Franck–Condon transition can approximately be described by 17 instead of all 36 valence states. The approach shall be particularly useful for reducing the numerical effort of semiclassical and quantum dynamics simulations.