THEORETICAL STUDIES OF CO/Ni(lW): GEOMETRY, VIB~~ONAL FREQUENCIES AND IONIZATION POTENTIALS FOR THE ON-TOP SITE
نویسندگان
چکیده
The chemisorption of CO on the (100) surface of Ni has been studied using an Nit, cluster and generalized valence bond (GVB) methods. CO is found to bond perpendicular to the Ni surface with optimized Ni-C and C-O bond distances of 1.94 and 1.15 A, respectively. The cakulated Ni-CO bond strength is 29.7 kcal (experimental values 30-32 kcal). Vibrational frequencies are calculated to be 401 cm-’ for Ni-C stretch, 327 cm-” for NiCO bend, and 2129 cm-’ for CO stretch. This decrease of the CO frequency by 71 cm ’ from the free molecule value is consistent with experiment based on self-consistent calculations of the positive ion states. We propose a new explanation for the loss of one PES peak upon chemisorption.
منابع مشابه
SURFACE SCIENCE LETTERS GEOMETRY, VIBRATIONAL FREQUENCIES, AND IONIZATION POTENTIALS FOR CO/Ni( 100); EXPLANATION OF THE DISAPPEARANCE OF THE So PEAK IN PES
Using a cluster of 14 Ni atoms to model an Ni(100) surface, we have used ab inltio methods (generalized valence bond) to calculate geometry, vibrational frequencies and ionization potentials for CO chemisorbed at the on-top site. The Nil4 cluster consisted of atoms at the corners and faces of a cube, and the CO was bonded to an Ni atom at the center of one face. This on-top site has been establ...
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