Violation of the Equipartition Theorem for Thermally Insulated Clusters   of Atoms with Different Masses
  An expression is derived for calculating microcanonical-ensemble averages of the kinetic energies of atoms of different types in clusters isolated from the environment. This expression is a natural generalization of the solution to the problem of hard spheres with different masses to a system with a many-particle interatomic interaction potential. The dynamics of a C8H8 cubane is simulated numerically. The data on the numerical simulation confirm the validity of the results obtained. 
L. A. Openov, A. I. Podlivaev