Photoionisation cross section calculations using Dyson amplitudes: results for Ne

Photoionisation cross sections of the main ionisation process of neon have been calculated for a wide range of photon energies. The partial cross sections were computed as a sum of a contribution expressible in terms of the Dyson amplitude corresponding to the ionisation processes considered plus a correction term. The numerical results obtained, in satisfactory agreement with the experiment, show, as expected, that for outer-shell ionisation the correction term decreases rapidly with the photon energy. For inner-shell ionisation, however, the correction term appears to be still important at relevant ( approximately 100 eV) energies of the photoelectron. Results given by different choices of the photoelectron waves are also presented.