A computational study on geometries, electronic structures and ionization potentials of MSi15 (M = Cr, Mo, W) clusters by density functional method

Geometry optimization, electronic structures and ionization potentials of MSi15 (M = Cr, Mo, W) clusters are carried out under the constraint of well-defined point-group symmetry at the level of Vesko-Wilk-Nusair with generalized gradient approximation considering of Becke correction. The most stable structures are found for MSi15 (M = Cr, Mo, W) dusters. Stabilities of Si-15, MSi15+ and MSi15 (M = Cr, Mo, W) clusters are presented and discussed. In addition, we comment on the electron transfer within the clusters. Theoretical results indicate that properties of Si-15 cluster are influenced by the transitional metal (TM) (TM = Cr, Mo, W). Mulliken atomic net populations of TM in MSi15 and MSi15+ (M = Cr, Mo, W) clusters are reported, and the net populations of Si atoms are influenced by shifting electrons out of Si atoms to the TM (TM = Cr, Mo, W) atom. Charge transfer from impurity TM to Si atoms is the main factor that degrades the efficiency of the semiconductor. (C) 2001 Elsevier Science B.V. All rights reserved.