Eur. Phys. J. D 1, 197-205 (1998)
https://doi.org/10.1007/s100530050081

Can we rationalize the structure of small silicon-carbon clusters?

Laboratoire de Chimie Théorique CEA-CE Saclay DSM/DRECAM/SPAM 91191 Gif-sur-Yvette, France

Corresponding author: ^a marjorie@callisto.saclay.cea.fr

Received: 20 October 1997
Revised: 16 December 1997
Accepted: 17 December 1997
Published online: 15 February 1998

Abstract

A theoretical study of clusters with using density functional theory is presented. Tests of various functionals demonstrate that local spin density approximation (LSDA) is the most adequate functional for the study of these systems. Structures, vibrational frequencies, and IR intensities of the lowest energy isomer of the studied clusters obtained using LSDA are described, and the unusual properties of the Si-C clusters are discussed. A quantitative analysis of the obtained structures was carried out, and relations between the coordinations, interatomic distances, and angles observed in the Si-C clusters were obtained through introduction of the notion of coordination. This analysis also shows that the carbon atoms mainly exhibit sp and sp² hybridizations, and that a majority of silicon atoms do not hybridize. This study is the first step of the implementation of a semi-empirical potential, which would describe the moderately small Si-C clusters.