Calculations of elastic electron scattering byH2for fixed nuclei

Cross sections for elastic electron scattering by the ${}_{}{}^1{}_{}{}^{}\mathrm{\Sigma }_{\mathrm{g}}^{+}{}_{}{}^{}$ ground state of ${\mathrm{H}}_2$ are computed at fixed internuclear distance 1.402$a_0$, for incident energies up to 13.6 eV. Variational R-matrix calculations are supplemented by asymptotic distorted-wave calculations for higher partial waves and by a residual Born-approximation sum for the polarization potential. Polarization response is treated dynamically, using ${}_{}{}^1{}_{}{}^{}\mathrm{\Pi }_{\mathrm{u}}^{}{}_{}{}^{}$ and ${}_{}{}^1{}_{}{}^{}\mathrm{\Sigma }_{\mathrm{u}}^{+}{}_{}{}^{}$ polarization pseudostates obtained by variational calculations. Pseudostate closed channels are included in the coupled equations integrated outside an R-matrix sphere.