ON THE SAMPLING OF MICROCANONICAL DISTRIBUTION FOR ROTATING TRIATOMIC-MOLECULES

For a rotating harmonic molecule, we suggest a successive sampling met hod from a microcanonical ensemble which allows one to specify the ene rgies of any number of normal modes, and the energies of active and ad iabatic rotations. The method is checked by comparing the calculated h istogram distributions of various dynamical variables with those predi cted by the rigid rotor-harmonic oscillator model. We also compared th e distributions over rotational energies for a model of free SO2 molec ule, and the mean energies transferred in SO2-Ar collisions as calcula ted with the sampling of initial conditions by our method and by the M arkov chain sampling procedure. The successive sampling method can be recommended for specifying initial conditions in studies of the collis ional energy transfer under condition of local excitation.