PM3 semiempirical electronic structure calculation of capped and uncapped CdS nanoparticles

Abstract

In this paper, CdS nanoparticles of various sizes are theoretically studied. We have used the PM3 semiempirical Hamiltonian of Stewart to compute their ground state electronic structures on the assumed zincblende like geometries, optimized with the SYBYL molecular mechanics force field. Suitable capping agents induce surface modification of these nanoparticles. In order to reduce the computational cost, the experimental capping agents (2-ethyl-hexanoate ions) are modeled by formiate ions. We compare the stability of the naked and capped nanoparticles in the gas phase with the solvated species in the dimethylsulfoxide solvent. The evolution of the HOMO-LUMO gaps has been determined for these CdS particles, both naked and capped. (C) 1999 Acta Metallurgica Inc.