Noniterative Integral-Equation Approach to Scattering Problems.

A procedure which allows for both open and closed channels with exchange and orthogonality is formulated for a multichannel scattering process. Noniterative integral-equation theory is used to solve the coupled integrodifferential equations of the scattering problem from zero out to some transformation point where the reactance matrix is projected out to its asymptotic value by using a matrizant technique. The method is applied to a two-channel model which has some of the features of a $1s\ensuremath{-}2p$ approximation for $e$-H scattering.