  Detailed studies of the thermodynamic properties of selected binary
Lennard-Jones clusters of the type X_{13-n}Y_n (where n=1,2,3) are presented.
The total energy, heat capacity and first derivative of the heat capacity as a
function of temperature are calculated by using the classical and path integral
Monte Carlo methods combined with the parallel tempering technique. A
modification in the phase change phenomena from the presence of impurity atoms
and quantum effects is investigated.
