Discrete-basis-set method for electron-molecule continuum wave functions

We present a method for calculating the continuum wave function in electron-molecule scattering for an $N\times N$ discrete-basis-set representation of the potential. The method is based on the $T$-matrix method introduced by Rescigno, McCurdy, and McKoy. In this work, the wave function is used in a prescription for the variationally corrected partial-wave $K$ matrix analogous to Kohn's variational formula for the scattering amplitude in three dimensions. Results presented for $e^{-}$-${\mathrm{H}}_2$ scattering in the static-exchange approximation are in good agreement with other accurate calculations.