Study of the 2p → np (n=3-6) excitation processes accompanying 1s photoionization of Ne

We measured the relative intensities of satellite lines in the 1s core-level photoemission spectra of Ne, as a function of excitation energy, using high-brilliant soft x-ray undulator radiation. Measured excitation functions for these satellite lines were merged with the previously reported results and discussed in terms of the intra-atomic electron-electron correlations. Some results have suggested that the internal electron scattering might play an important role in characterizing the near-threshold behaviour for the 2p -> np excitation process accompanying 1s photoionization. The observed intensity ratios of the satellite lines relative to the main line were analysed with the aid of the analytic Thomas model. The observed near-threshold behaviours were also compared with the simple model calculations which take account of both the sudden creation of an inner-shell vacancy and the Coulomb interaction between the ionized electron and atomic electrons. The comparison has implied that both the amplitude and the shape of the measured excitation functions cannot be satisfactorily explained by the simple model calculations. This fact may call on an improvement in the theoretical treatment in such simple model calculations.