Statistical thermodynamics of cluster phase transitions

We study phase transitions of two-dimensional Lennard-Jones drops. A wide excitation energy range is studied, which encompasses the solid-like to liquid-like phase transition, the weakly evaporating liquid drop and multifragmentation. We are able to calculate the caloric curve for the whole energy range, it displays the standard plateau of the solid-like to liquid-like transition and new plateau which denotes the evaporation and multifragmentation phase transitions. We further calculate the maximum local Lyapunov exponent of the drops as a function of the energy. This curve shows a peak in the region of evaporating liquid.