Taking into account non-dynamical correlation effects in ab initio chemisorption cluster model calculations

Abstract

Chemisorption calculations of atomic hydrogen and oxygen over a Cu 5 cluster model simulating the (100) metal surface have been carried out to illustrate several procedures that can be used to take into account non-dynamical and dynamical correlation effects. Non-dynamical correlation effects contribute to the total binding energy by about 20% and lead to a shorter equilibrium distance. For Cu 5O dynamical correlation effects are very important and they can be recovered by second order perturbation theory (MP2) calculations correlating only those electrons occupying active orbitais.