Geometrical,spectroscopic, and magnetic properties of an oxygen atom adsorbed on the Ni(100) surface

Spin-polarized linear combinations of Gaussian-type orbital–model core potential–local spin density (LCGTO –MCP –LSD ) computations have been performed for oxygen chemisorption on a Ni(100) surface simulated by four different clusters. Results show that the oxygen atom chemisorbs preferentially on the fourfold hollow site with an equilibrium distance of 1.931 Å and a vertical vibrational frequency of 401 cm^?1. The corresponding experimental values are 1.960 Å and 423 or 430 cm^?1. A satisfactory agreement with experiment is also found for the adsorption energy (6.7 vs. 5.6 eV). The bridge position lies at only 0.4 eV above the fourfold hollow one. It is found that oxygen adsorption leaves the bare cluster total spin magnetic moment unchanged, but induces appreciable reductions of the local atomic moment on the surface nickel atoms. © 1993 John Wiley & Sons, Inc.