Electron-molecule scattering treated with the use of separable approximations for the nonlocal part of the interaction: Static exchange calculations for $e^{\mathrm{-}}$+${\mathrm{H}}_2$ and $e^{\mathrm{-}}$+${\mathrm{N}}_2$

We have formulated and applied a method for solving the low-energy electron-molecule collision problem. This method treats the scattering by the local and nonlocal parts of the interaction differently. A differential equation method is used to obtain a solution of the set of coupled equations which describe the scattering by the (nonspherical) local potential. The T-matrix expansion method is used to account for the scattering by the nonlocal part of the interaction. The method is tested by application to low-energy $e^{\mathrm{-}}$-${\mathrm{H}}_2$ and $e^{\mathrm{-}}$-${\mathrm{N}}_2$ scattering in the static exchange approximation.