Ab-initio calculations of cadmium sulfide clusters - fragments of thiolate complexes

A series of clusters constructed from cadmium and sulfur atoms beginning from a central cadmium is considered as fragments of the bigger cadmium sulfide clusters bounded by the shell of thiolate ligands. The sequence of these clusters includes CdS4, CdS4H4, Cd13S4, Cd13S16, Cd13S16H12. Hydrogen atoms are used to simulate thiolate ligands. The MO LCAO RHF SCF calculations were performed for ground states, and equilibrium geomerties were obtained which show the essential difference in the Cd-S interatomic distances for inner and external bonds. Energies of the first allowed electronic transition vary non-monotonously from 9.86 eV for the smallest clusters to 3.39 eV for Cd13S16H124+. Cd13S16-clusters are proposed as possible intermediates in the growth of large observed structures. (C) 1999 Published by Elsevier Science Ltd. AU rights reserved.