Collisional energy transfer in H2(vab,jab)+H2(vcd,jcd)

Quasiclassical trajectory studies were carried our on the H-2(v(ab), j(ab)) + H-2(v(cd), j(cd)) system to survey the effects of initial vibrational, rotational, and translational energy on the collisional energy transfer behavior at total energies of 0.1 and 0.25 E-h. When the internal energy of the collider is low, repulsive interactions dominate and the energy transfer in the target molecule resembles the behavior observed for the He + H-2 system, in which interconversion of vibrational and rotational energy is strongly correlated. By contrast, an internally excited collider can yield energy transfer behavior with more randomly distributed vibrational and rotational changes, similar to that observed when a H atom is the collider. Implications for master equation calculations an discussed, (C) 1998 American Institute of Physics.