[Abstract list] [Previous] [Next] [Home]
Chemical Physics Letters 230 (1994) pp.501-506
Gradient Corrections in Density Functional Theory Calculations for Surfaces: CO on Pd(110)
University of Cambridge, Department of Chemistry, Cambridge CB2 1EW, England
University of Cambridge, Cavendish Laboratory, Cambridge CB3 0HE, England
Abstract
Ab initio total energy calculations have been performed for CO
chemisorption on Pd(110). Local density approximation (LDA)
calculations yield chemisorption energies which are
significantly higher than experimental values but inclusion of
the generalised gradient approximation (GGA) gives better
agreement. In general, sites with higher coordination of the
adsorbate to surface atoms lead to a larger degree of
overbinding with LDA, and give larger corrections with GGA. The
reason is discussed using a first-order perturbation
approximation. It is concluded that this may be a general
failure of LDA for chemisorption energy calculations. This
conclusion may be extended to many surface calculations, such
as potential energy surfaces for diffusion.