A simple chemisorption theory and its application to transition adatoms on transition metals

Abstract

Calculates the binding energy of an adatom on a transition metal substrate taking into account: the band term which is treated in the tight-binding approximation; and electronic correlation contribution obtained from a perturbation theory within the Hubbard model and a pairwise repulsive potential of the Born-Mayer type. The binding energy is minimised with respect to the position of the adsorbate keeping neutral all atoms involved in the bonding. The authors find that bond lengths increase with the coordination number of the adsorbate. The most stable site is generally the site with maximum coordination but exceptions exist and are discussed. Numerical results of binding energy and surface diffusion activation energies at 0K for transition adatoms on several faces of BCC transition metals are in good agreement with experiments.