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The transition energies and electric dipole (E1) transition rates of the K, L, and M lines in neutral Np have been theoretically determined from the MultiConfiguration Dirac—Fock (MCDF) method. In the calculations, the contributions from Breit interaction and quantum electrodynamics (QED) effects (vacuum polarization and self-energy), as well as nuclear finite mass and volume effects, are taken into account. The calculated transition energies and rates are found to be in good agreement with other experimental and theoretical results. The accuracy of the results is estimated and discussed. Furthermore, we calculated the transition energies of the same lines radiating from the decaying transitions of the K-, L-, and M-shell hole states of Np ions with the charge states Np1+ to Np6+ for the first time. We found that for a specific line, the corresponding transition energies relating to all the Np ions are almost the same; it means the outermost electrons have a very small influence on the inner-shell transition processes.

The radiative and Auger decay processes of K-shell ionized Np ions are studied theoretically using the flexible atomic code (FAC). Relativistic effects, Breit interaction, QED corrections and nuclear finite mass and volume effects are considered systematically. The resulting calculated K x-rays and Auger spectra of Np are compared with the measured spectra emitted after the electron-capture (EC)-decay of mass-separated 237Pu. The general consistency between theory and experiment is good; the relative intensities and relative positions of the peaks in the measured spectra are reproduced with good accuracy, in spite of the existence of different ways to produce the primary K-shell vacancy, enabling identification of the observed structure in the experimental spectra. We find that most of the radiative transition rates are greater than the Auger transition rates, and the latter decrease rapidly with the transfer of initial vacancies to the outer shell.

In this paper, the Ne 1s photoelectron spectrum and the corresponding Auger decay processes have been investigated theoretically by using the GRASP92, RATIP and the recently developed RERR06 codes based on the multi-configuration Dirac-Fock method. Good overall agreement was found between the present calculations and the previous theoretical and experimental results. By analyzing the Auger decay processes of the photoionization satellite state Ne+1s-12p-1（1,3Ｐ）3p, it was found that the spectator Auger decay is the dominant decay mode and the Auger intensity of the Ne+1s-12p-1（1Ｐ）3p is greater than that of the Ne+1s-12p-1（3Ｐ）3p as a whole. Meanwhile, the relative populations of the final ions Ne+, Ne2+and Ne3+produced by the photoionization satellite state Ne+1s-12p-1（1,3Ｐ）3p were predicted to be 0.02, 0.58 and 0.41, respectively.