Molecular dynamics (MD) simulations have been run to study the evaporation process of a model Lennard-Jones cluster, namely ArnXm, in which X is an artificial atom whose properties can be adjusted. The influence of changes in its Lennard-Jones parameters (binding energies D and distance sigma) and its mass has been explored in a systematic way in the case of various seven-atom clusters on: (i) The outcome of Ar3X4 evaporation (chemical composition of the product cluster) and (ii) the evaporation rate constant in the series of Ar7-mKrm. It is shown that a proper choice of the X atom parameters allows to enhance the evaporation rate constant of ArnX in a way which enables to explore by MD the dynamics at much lower values of internal energy. Consequently the "melting" transition in Ar-7 and Ar-13 product clusters can be investigated by the analysis of the mean kinetic-energy release. In the latter case it is shown to be in excellent agreement with phase space theory predictions. (C) 2003 American Institute of Physics.