Structure and transformation: Large molecular clusters as models of condensed matter

This paper reviews investigations of homogeneous nucleation in phase transitions in large molecular clusters. The principal techniques brought to bear are electron diffraction analyses of transformations in clusters formed by condensation of vapor in supersonic expansions and computer simulations of spontaneous phase changes in clusters. Results obtained to date are contrasted with those of larger systems and interpreted in terms of nucleation theory. The review also refers to some unresolved aspects of nucleation theory.