ELECTRONIC-STRUCTURE AND PROPERTIES OF THE CARBONYLS TICO AND TI7CO AND CARBENES TICH2 AND TI7CH2 BY DENSITY-FUNCTIONAL METHODS

Density functional theory (DFT) calculations of the electronic structu re and properties of clusters of one and seven Ti atoms interacting wi th CO and CH, are reported because of their importance in heterogeneou s catalysis (especially in Fischer-Tropsch synthesis). The local spin- density approximation (LSDA), i.e., Slater's exchange functional coupl ed to the Vosko-Wilk-Nussair correlation functional, as well as the ge neralized-gradient approximation (GGA), using Becke's 1988 exchange fu nctional and Perdew's 1986 correlation functional (BP method) were app lied to the study of the clusters using a triple-zeta plus polarizatio n (TZP) basis set. Tripler and quintuplet states of the clusters were studied, and the dissociation energies are provided. The DFT results a re compared with other values available in the literature and found to be of reasonable accuracy. (C) 1997 John Wiley & Sons, Inc.