Surface Science 169 (1986) L273-L277 L273 North-Holland. Amsterdam SURFACE SCIENCE LETTERS A PARAMETRICAL INVESTIGATION FOR THE STRUCTURE OF SMALL CLUSTERS ~. ERKO(~ Department of Physics, Middle East Technical University, Ankara, Turkey T. HALICIOt~LU Department of Materials Science and Engineering, Stanford Unwersio; Stanford, California 94305, USA and O. PAMUK Department of Chemistry, Middle East Technical UniversiO', Ankara, Turkey Received 18 October 1985; accepted for publication 3 January 1986 A parametrical analysis was performed to investigate the effect of the substrate on the structure of deposits. Calculations are based on a static approach which employs a semi-empirical potential function comprising two-body and three-body terms. Results indicate that three-body interactions, in particular, play a significant role in determining the energetically most favorable structure of deposits. In studies such as nucleation, crystal growth, epitaxy and catalysis the details of the structure and stability of deposits (i.e., microcrystals or over- layers) are very important [1-3]. In the molecular theory of catalysis, in particular, knowledge of the precise geometry of the equilibrated clusters is highly desired in order to understand the selectivity problem. Many attempts have been made to predict theoretically the structure of isolated small clusters; however, investigations involving the effect of the support are rather scarce [4 6]. In general, the minimum energy configuration of an isolated cluster is altered when the cluster is deposited on a support. Because most of the experimental observations are associated with supported clusters, the influence of the support on the structure of clusters is very important and must be well understood for proper interpretation of many experimental results [1,2]. In the present work, the effect of the substrate on the structure of deposits was investigated parametrically. Calculations are based on an energy minimi- zation technique and employ a semi-empirical potential energy function which 0039-6028/86/$03.50 © Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division)