Variationally corrected discrete-basis-set calculation for electron-molecule scattering in the static-exchange approximation

We present a method for including a variational correction in the discrete-basis-set method for electron-molecule scattering introduced by Rescigno, McCurdy, and McKoy. Our prescription for variationally corrected partial-wave K-matrix elements is based on Kohn's formula for the variationally stable scattering amplitude in three dimensions. The method is applied to e--H2 scattering in the static-exchange approximation, and the effect of choosing different trial basis sets is shown. Our results are in good agreement with the results of other accurate calculations.