Ab-initio calculations of cadmium sulfide clusters - fragments of thiolatecomplexes

A series of clusters constructed from cadmium and sulfur atoms beginning fr om a central cadmium is considered as fragments of the bigger cadmium sulfi de clusters bounded by the shell of thiolate ligands. The sequence of these clusters includes CdS4, CdS4H4, Cd13S4, Cd13S16, Cd13S16H12. Hydrogen atom s are used to simulate thiolate ligands. The MO LCAO RHF SCF calculations w ere performed for ground states, and equilibrium geomerties were obtained w hich show the essential difference in the Cd-S interatomic distances for in ner 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 fo r Cd13S16H124+. Cd13S16-clusters are proposed as possible intermediates in the growth of large observed structures. (C) 1999 Published by Elsevier Sci ence Ltd. AU rights reserved.