A theoretical procedure to treat elastic electron-molecule collision usingthe configuration-interaction method

A procedure to use a configuration-interaction (CI) wavefunction of the tar get to determine the potential interaction in the electron-molecule collisi on theory is proposed. Static, exchange and polarization contributions are obtained explicitly. As a first application the method is used to study ela stic scattering by two molecules with different symmetries, H-2 and CH4. Di fferential cross sections (DCS) using Hartree-Fock (BF) and CI wavefunction s are presented and the effect of electron correlation analysed. The DCS we re obtained using the Schwinger variational iterative method and the method of continued fractions. It is observed that the discrepancies between HF a nd CI results are more significant for low energies and small angles. Altho ugh our procedure is valid for arbitrary energies, it could be most useful for electron-molecule collision in the low energy range.