Computer simulation of cluster decay

Lennard-Jones metastable clusters consisting of 5 to 1030 atoms have been studied by molecular-dynamics simulation. Evaporation rate constants and caloric equations of state have been obtained in the microcanonical ensemble and with the use of RRK theory of unimolecular reactions and a local harmonicity approximation the canonical rate constants have been evaluted. The comparison with classical nucleation theory, specifically with the liquiddrop model, shows that the calculated equilibrium vapour pressure is significantly higher than theoretical one for small clusters, whereas the microcanonical results agree with theory.