Nondipole effects in the photoionization of neon: Random-phase approximation

The random-phase approximation (RPA) is applied to study nondipole corrections to the angular distribution of photoelectrons from the n = 2 shell of Ne. Calculations of the parameters gamma(nl) and delta(nl) arising from E-1-E-2 interference effects are carried out for the 2s and 2p subshells of Ne in the photon energy range 100-2000 eV. For the 2s shell, the RPA calculations show small effects of correlation near the 2s threshold energy, but are otherwise in agreement with independent-particle approximation (IPA) calculations. The RPA and TPA values of gamma(2s) are also in agreement with experiment. For the 2p shell, a small difference between RPA and IPA calculations of the nondipole parameters is found for energies near the Is threshold; however, both RPA and IPA calculations of the parameter gamma(2p) + 3 delta(2p) disagree significantly with experimental measurements for photon energies above 1000 eV. [S1050-2947(99)09605-5].