A detailed calculation of the lowest partial wave of Σu+symmetry in low energy e+-H2scattering

Above incident energies of about 2 eV, the contribution to the total cross section in e + -H 2 scattering from the Sigma g + symmetry is insufficient to account for the experimental value. The next symmetries from which significant contributions can be expected as the energy increases above 2 eV, are the Sigma u + and Pi u symmetries. The authors present a calculation of the lowest partial wave of Sigma u + symmetry carried out using the Kohn variational method and a trial function which includes not only Hylleraas-type functions, which are important for taking into account short-range interactions, but also functions appropriate for taking into account long-range polarisation. A comparison is made with an R-matrix calculation for the Sigma u + symmetry, which has been carried out by Danby and Tennyson (1989). Both calculations predict that the contribution to the total cross section from this symmetry is much too small to reduce significantly the discrepancy with experiment above 2 eV.