STRUCTURAL DYNAMICS OF CLUSTERS NEAR MELTING

Unlike their bulk counterparts, clusters show a smooth transition from a low-temperature solidlike to a high-temperature liquidlike phase. P revious studies have established the variation of maximum Lyapunov exp onent and the presence of 1/f noise in the power spectra of potential energy fluctuation as ''dynamical indicators'' of this transition. Her e we propose that the coexistence can be efficiently studied using the self-part of the dynamic structure factor (DSF). To support our claim , we present molecular dynamics simulation results for the Ar-13 clust er. We find that the spectral features of the DSF are strongly wavelen gth dependent and its long time behavior is anomalous, a result of the dynamic excursion between the two coexisting phases.