On Hydrogen Chemisorption on Simple Metals

Abstract

AbstractA theoretical study of the single hydrogen adatom chemisorption on free electron‐like metal surfaces is performed using an earlier published microscopic approach which includes the possibility of an influence of the adatom orbital occupancy on the hybridization of the adatom and substrate electron wave functions. The matrix elements inherent to the model are calculated from first principles using free‐electron wave functions for describing the substrate metal and treating the IS‐orbital of the adatom as an auxiliary orbital. The effect of the screening charge is considered phenomenologically in terms of an effective on‐adatom Coulomb integral. The self‐consistent Hartree‐Fock calculations show much more preference for hydrogen absorption rather than adsorption and slightly more adatom substrate—surface distance‐dependence of the chemisorption energy compared to results obtained within the local density functional method.