title: Fast initial decay of molecular excitations at insulator surfaces.
abstract: We investigate the initial decay of electron-hole excitations in a molecular layer after adsorption on an insulator substrate surface. This is done within ab initio many-body perturbation theory by calculating the time propagation of excited two-particle states. For a CO monolayer adsorbed on the MgO(001) surface we find very fast decay processes with lifetimes that are about 5 times shorter than the transfer of single charge carriers. This is due to a strong coupling of the molecular excitations to charge-transfer-exciton states between the adlayer and the substrate.
authors.affiliation: Institut für Festkörpertheorie, Universität Münster, 48149 Münster, Germany.
authors.forename: Neng-Ping
authors.initials: NP
authors.lastname: Wang
authors.forename: Michael
authors.initials: M
authors.lastname: Rohlfing
authors.forename: Peter
authors.initials: P
authors.lastname: Krüger
authors.forename: Johannes
authors.initials: J
authors.lastname: Pollmann