CLUSTER ANALOGS OF BINARY ISOTOPIC MIXTURES - PATH-INTEGRAL MONTE-CARLO SIMULATIONS

The structure of quantum clusters composed of binary isotopic mixtures is studied using Fourier path integral Monte Carlo simulations. Such clusters display a purely quantum analog of the segregation phenomenon observed in classical binary dusters with the lighter isotope prefere ntially located on the cluster surface and the heavier isotope in the cluster interior. A parametric multistage sampling scheme is developed to equilibrate such quantum mixtures. The behavior of a single isotop ic impurity in a quantum cluster is examined as a function of impurity mass, temperature and cluster size. Isotopic segregation effects in m ixed para-H-2/ortho-D-2 clusters are shown to be striking. (C) 1996 Am erican Institute of Physics.