Construction of the R-matrix for three-dimensional, reactive atom--diatom scattering: application to H+H2

In an extension of previous work (R.B. Walker, J.C. Light and A. Altenberger-Siczek, J. Chem. Phys. 64, 1166(1976)), equations for the accurate quantum mechanical treatment of three body rearrangement collisions are presented in the R-matrix language. These equations describe how the solutions to Schrodinger's equation in three separate regions of configuration space (each containing one asymptotic atom + diatom arrangement) are matched smoothly to each other. The symmetry of the matching equations is discussed in detail. Within the R-matrix formalism, unitary S-matrices may be constructed for arbitrary atom-diatom mass combinations and for small target wave function basis expansions. Applications of this method to the three dimensional H + H2 (labelled nuclei) exchange reaction are reported, and comparison is made to prior work