Solid-to-liquid phase change and fragmentation in C60

We present a study of the thermodynamical properties of C60 in the microcanonical ensemble. Solidlike and metastable liquidlike form can be identified in the low energy and in the high energy range, respectively. The transition between the two phases is characterized by a finite energy range, in agreement with general theories of cluster melting. In particular, we have observed that the melting is preceded by a highly isomerized transition region where a sizeable atomic mobility is achieved via hopping between different isomer structures.