Dynamics of Atomic Structure

Abstract

Fluctuation of atomic structures of metal microclusters is observed by using an electron microscope of atomic resolution with a television camera. Such a structural fluctuation is one of the characteristics of microclusters. By using a computer, dynamical properties of small microclusters are studied for the size N = 13 bound by the Lennard-Jones interaction. The coexistence of solid-like and liquid-like phases is pointed out at the effective temperature between those for melting and freezing. On the other hand, for the transition-metal cluster of size N = 6, a fluctuating state accompanying no atomic diffusion is found just below the melting temperature, and a transition to permutation isomers accompanying atomic diffusion just above the melting temperature. Thermal properties of transition-metal microclusters are studied by using Monte-Carlo simulations in both cases of absence and presence of a magnetic interaction. It is observed that a sharp magnetic transition exists even in the small magnetic cluster of size N = 7.