The accuracy and efficiency of ab initio density functional theory calculat
ions depend critically on the choice of pseudopotenlial. In this study, the
merits of using large-core pseudopotentials for the dissociative chemisorp
tion of oxygen on rhodium are discussed. The results show that these effici
ent pseudopotentials yield adsorption energies and bond distances of the ox
ygen atom to rhodium that are in close agreement with calculations performe
d with small core pseudopotentials. However, to compute the dissociative ch
emisorption energy, a small-core calculation of the free O-2 molecule must
also be performed to ensure accurate results. The use of pseudopotentials w
ith different core radii for different aspects of the calculation leads to
enhanced efficiency. (C) 1999 Elsevier Science B.V. All rights reserved.