Ab initiooptical potentials applied to low-energye−H2ande−N2collisions in the linear-algebraic approach

We propose a method for constructing an effective optical potential through which correlation effects can be introduced into the electron-molecule scattering formulation. The optical potential is based on a nonperturbative, Feshbach projection-operator procedure and is evaluated on an $L^2$ basis. The optical potential is incorporated into the scattering equations by means of a separable expansion, and the resulting scattering equations are solved by a linear-algebraic method based on the integral-equation formulation. We report the results of scattering calculations, which include polarization effects, for low-energy $e-{\mathrm{H}}_2$ and $e-{\mathrm{N}}_2$ collisions. The agreement with other theoretical and with experimental results is quite good.