Molecular dynamics calculations of melting and fragmentation of Ar and Ag clusters

Melting and fragmentation, due to collisional dissociation, of Ar and Ag clusters containing from 30 to 500 atoms have been studied with an isothermal molecular dynamics simulation method using classical forces. In the case of melting it has been found for both elements that a temperature increase leads to a continuous transition from a softening of the bonds to fragmentation. This behaviour is atypical and an approximate scaling of the temperature exists which converts the melting behaviour from that of Ar to that of Ag. On the contrary, in the case of collisional dissociation a perceptible fragmentation yield is observed in Ar whereas in Ag the input energy leads only to an increase of the translational energy and to rigid motions.