SEMICLASSICAL CALCULATION OF ROTATIONAL-EXCITATION OF ATOM-SYMMETRICAL TOP SCATTERING

A semiclassical approach is applied to calculating the state-to-state cross sections of rotational excitation of ammonia molecule scattering with the argon atom. Semiclassical theory is more useful in studying heavy molecular scattering. Ammonia molecule is regarded as a rigid sy mmetric top and argon as a structureless atom. The inversion motion of ammonia is not taken into account. We make use of classical action-an gle variables to describe the degrees of freedom of the system. The ab initio potential is used, and at two different energies the computing of total cross sections are performed by using the Monte Carlo proced ure. Good agreements with close-coupling calculations and crossed mole cular beam experiment are obtained. The semiclassical approach thus ap pears to be valid for ammonia-argon scattering system. (C) 1997 John W iley & Sons, Inc.