Chemical bond effects on the low energy electronic stopping power: theory

Abstract

We discuss the applicability of a modified version of the Firsov model to account for the low-energy electronic stopping cross section ( S e ) due to molecular targets. We employ floating spherical Gaussian orbitals (FSGO), which reproduce major trends in electronic and geometrical structure of molecules. Two advantages of using FSGO are: i) each localized orbital is classified as inner shell, bonding and lone-pair species, hence a natural partitioning of S e from each type of orbital is possible and ii) a simple analytical expression for the orbital contribution to S e is obtained after averaging over all molecular orientations. Our results show an explicit dependence of S e on the geometric structure of the molecule as well as on the core and bond character.