A chemical and theoretical way to look at bonding on surfaces

TLDR

Surface chemistry is studied using solid‑state theory that incorporates chemical interpretation, highlighting that surface‑adsorbate interactions can differ from simple molecular binding by involving two‑orbital four‑electron and zero‑electron bonding mechanisms. The method starts from delocalized band structures and uses density‑of‑states decompositions and crystal orbital overlap populations to trace local chemical interactions, treating the surface and bulk as electron reservoirs at the Fermi level. The approach enables construction of surface interaction diagrams and frontier orbital arguments, showing that chemisorption represents a compromise between dissociative adsorption and surface reconstruction.

Abstract

An account is given of a theoretical approach to surface structure and reactivity that is within the framework of solid-state theory, yet strives for chemical ways of interpretation. One begins from highly delocalized band structures, but introduces interpretational tools (density-of-states decompositions, crystal orbital overlap populations) that allow a tracing of local, chemical acts. It is quite feasible to construct interaction diagrams for surfaces, and to make frontier orbital arguments, just as for molecules. There are some interesting ways in which the surface-adsorbate interaction differs from simple molecular binding---in particular, in the way that two-orbital four-electron and zero-electron interactions can turn into bonding. The surface and bulk acting as a reservoir of electrons or holes at the Fermi level are important in this context. Chemisorption emerges as a compromise in a continuum of bonding whose extremes are dissociative adsorption and surface reconstruction.