Low-energy electron-molecule scattering: Application of coupled-channel theory toe-CO2collisions

A theoretical coupled-channels investigation of $e$-C${\mathrm{O}}_2$ scattering is reported for incident electron energies from 0.07 to 10.0 eV. The fixed-nuclei approximation is made with the molecule in the ground $X{}_{}{}^1{}_{}{}^{}\Sigma _{\mathrm{g}}^{+}{}_{}{}^{}$ state and the nuclei frozen at their equilibrium positions. The $e$-C${\mathrm{O}}_2$ interaction potential consists of an ab initio electrostatic Hartree potential, an approximate local exchange potential, and a semiempirical polarization potential. The coupled-channel equations are formulated in a body-fixed reference frame using single-center coordinates and are solved by means of an integral-equations algorithm. Convergence of the highly anisotropic interaction potential and of the expansion of the scattering function are discussed. The asymptotic decoupling approximation and the Born approximation are also studied and found to be unsatisfactory methods for computing quantitatively accurate cross sections for low-energy $e$-C${\mathrm{O}}_2$ collisions. Converged coupled-channel total integrated, momentum-transfer and differential cross sections are presented, and the former are compared with experimental results, with special attention given to low scattering energies (≲0.1 eV).