Parameter-free model of the correlation-polarization potential for electron-molecule collisions

A model potential that includes both correlation and polarization effects is proposed for electron-molecule collisions. It is based, as suggested by O'Connell and Lane, on a hybridization of local electron-gas theory for short distances and the asymptotic form of the polarization potential. It is energy independent and very simple to apply, depending only on the molecular charge density and polarizabilities. The potential has been calculated for several molecules (${\mathrm{H}}_2$, ${\mathrm{N}}_2$, C${\mathrm{O}}_2$, HF, HCl, and CO); the crossing point between the correlation and polarization potentials is remarkably constant, averaging 0.96 eV. Application in scattering calculations for ${\mathrm{H}}_2$ and ${\mathrm{N}}_2$ yields very encouraging results.