A new approach to molecular collisions: Statistical quasiclassical method

A new approach is presented in which classical mechanics is combined with quantum statistics to describe molecular collisions. In this approach, the dynamics of collisions is described by classical trajectories as in the widely used quasiclassical method. However, initial and final internal states are represented in phase space in a quantum statistical way, using the Wigner distribution function. Results of calculations performed on a collinear He–H2 collision indicate that this new method is more accurate than the quasiclassical method, especially when the initial vibrational energy is low. Moreover, the new method is capable of describing classically forbidden processes that cannot be accounted for by the quasiclassical method.

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