On the algebraic approximation of scattering wave functions for molecular systems

The least-squares method for calculating scattering wavefunctions is discussed with respect to its applicability to molecular scattering events. Choosing an LCAO-like expansion, augmented by the appropriate asymptotic free components, for the radial wavefunction, one obtains a practical algorithm. The method reduces to the solution of an inhomogeneous system of linear equations. A basis set suitable for the description of molecular scattering events is suggested and its dependence on non-linear parameters is discussed. Applications are given for elastic s-wave scattering. The computational aspects of the method are discussed in detail, as well as generalizations to inelastic and reactive collisions.