Approximate factorised plane-wave Born calculations of the dipole (e,2e) cross sections for the Ne 2s and 2p and Ar 2p and 3p orbitals

Abstract

The factorised plane-wave Born approximation is employed with a Coulomb wavefunction description for the ejected electron in the calculation of single ionisation dipole (e,2e) cross sections of the Ne 2s and 2p and Ar 2p and 3p orbitals. These calculations are made using the frozen-core, or single-electron excitation, approximation with a final-state wavefunction both non-orthogonal and orthogonal to the initial-state wavefunction. Clementi-type analytic Hartree-Fock one-electron wavefunctions are used to describe the ground state. Results have been compared with the absolute experimental values of Lahmam-Bennani et al. (1984) and indicate reasonable agreement for the Ne 2s case. For the Ne 2p and Ar 2p and 3p orbitals, reasonable agreement is also obtained in the large-angle cases and in the binary lobe of the small-angle cases. However, there is poor agreement for the recoil peaks. For the Ar 2p case the binary peak and recoil peaks can be fitted to the data, but only with different values for the effective ion charge. The effective ion charge is found to increase with increasing scattering angle.