Orthogonal tight-binding molecular-dynamics simulations of silicon clusters

Orthogonal tight-binding molecular-dynamics methods are employed for describing small silicon clusters. Results obtained from the calculations of two different sets of tight-binding parameters are compared with one another and with those previously calculated using nonorthogonal tight-binding schemes and ab initio methods. Comparing the resulting cohesive energies and bond lengths, it is concluded that the orthogonal tight-binding matrix elements and repulsive potentials need to include the radial cutoff up to fourth-neighbor distance in diamond structure in order to reproduce ab initio results.