CHEMICAL-BOND EFFECTS ON THE LOW-ENERGY ELECTRONIC STOPPING POWER - THEORY

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.