Numerical implementation of reactive scattering theory

Algorithms for the effective calculation of reactive scattering probabilities are developed and tested on the hydrogenic atom–diatom system described by the Siegbahn–Liu–Truhlar–Horowitz potential energy surface. A three-dimensional finite element procedure is designed from a description in terms of hyperspherical coordinates. The Wigner–Eisenbud R-matrix theory is used for a recursive procedure which admits control with limits on the hyperradial propagation inward from an asymptotic region and for a symmetry preserving transformation to arrangement channel Jacobi coordinates.