Many-body effects on the melting and dynamics of small clusters

Using a potential recently proposed by Baskes [Phys. Rev. Lett. 83, 2592 (1 999)], we study the influence of the many-body interactions on the thermody namics and chaotic dynamics of small atomic clusters. With standard molecul ar dynamics simulations as well as parallel tempering Monte Carlo, we calcu late the complete heat capacity curves and the variations of the largest Ly apunov exponent with total energy. We observe that increasing the magnitude or decreasing the range of the many-body forces leads to an increase of ch aos and a decrease in the melting temperature. Decreasing the range of the many-body interactions also results in a significantly lower latent heat of melting.