Rapid and accurate evaluation of inelastic molecular cross sections

An inexpensive and accurate technique for computing inelastic cross sections has been developed by combining an exponential distorted wave (EDW) approximation and an effective Hamiltonian. This procedure is implemented through the use of uniformized WKB wavefunctions. It is shown to yield cross sections in semiquantitative agreement with those from exact calculations representing a wide range of physical parameters. The EDW cross sections can be used to compute rate constants, since good results are obtained even near threshold. The EDW procedure therefore provides a practical means for studying physical trends in cross sections, rate constants, and relaxation.