Molecular dynamics implementation in MSINDO: study of silicon clusters

Born-Oppenheimer molecular dynamics is implemented in the semiempirical self-consistent field molecular orbital method MSINDO. The method is employed for the investigation of the structure and dynamics of silicon clusters of various sizes. The reliability of the present parameterization for silicon compounds is demonstrated by a comparison of the results of simulated annealing and of density functional calculations of Si(n) clusters (n = 5-7). The melting behavior of the Si(7) cluster is investigated and the MSINDO results are compared to previous high-level calculations. The efficiency of the present approach for the treatment of large systems is demonstrated by an extensive simulated annealing study of the Si(45) and Si(60) clusters. New Si(45) and Si(60) structures are found and evaluated. The relative stability of various energy minimum structures is compared with density functional calculations and available literature data.