EFFECT OF CONFINEMENT IN THE ALPHA-CAGES OF ZEOLITE NACAA ON THE PROPERTIES OF AR-13 CLUSTER - A MONTE-CARLO STUDY

Monte Carlo simulations are reported for an Ar-13 cluster confined to an alpha-cage of zeolite A. The preferred geometry of the confined clu ster is different from that of the free cluster. The cluster has a cen tral atom only at low temperatures (below 40 K). The distribution of s hort-time potential energy averages can exhibit more than two peaks, u nlike in the free cluster. This is attributed to the heterogeneous env ironment provided by the zeolite. The properties of the confined clust er seem to be dictated by a competition between the guest-guest and gu est-host interactions. The value of the root-mean-squared bond length fluctuation, delta, on 'melting' is less than that observed for the fr ee cluster.