DFT AND MO CALCULATIONS OF ATOMIC AND MOLECULAR CHEMISORPTION ENERGIES ON SURFACE CLUSTER-MODELS

Density functional theory (DFT) (including gradient corrections) and M CPF calculations have been performed for atomic (H, C, N, O) and molec ular CHx (x = 1-3) chemisorption on cluster models of different sites of the Cu(100) surface. The DFT and MCPF results are in good agreement once the important effects of core-valence correlation have been acco unted for in the MCPF calculations by including contributions from a c ore polarization potential (CPP); in the DFT approach the core-valence correlation is obtained directly from the total density using the fun ctional. Very large effects on the four-fold hollow site binding energ y from core-valence correlation are found for C, N and CH. Several dif ferent DFT functionals were employed and compared in the calculations.