NEW METHOD FOR QUANTUM REACTIVE SCATTERING, WITH APPLICATIONS TO THE 3-D H+Hf REACTION

A method for carring out quantum-mechanical scattering calculations (J. Chem. Phys. 86 (1987) 62 13) is successfully applied to 3-D H + Hz reactive scattering. This new method (essentially the Kohn variational method, but applied directly to the S-matrix rather than to the K-matrix) is general, straightforward, variationally stable, and applies equally well to reactive (i.e., rearrange-ment) and non-reactive scattering process. Its most important practical feature, compared to other similar basis-set approaches, is that it requires matrix elements only of the Hamiltonian operator itself and not those involving the scattering Green’s function of some reference problem. Our calculations how that the method is numerically stable within a broad range of energies and converges fast with respect o basis set and numerical parameters. The method allows the use of a flexible distortion potential and contracted basis functions. Due to its generality and straightforwardness, the method is potentially powerful for studying more complex reactive systems beyond atom/diatom reactive scattering. 1