The photo-excitation and Auger decay processes of inner-shell double vacancy states 1s2s2p 6(1,3 S)3s3p of neutral neon atoms have been studied theoretically.Multi-configuration Dirac-Fock(MCDF) calculations have been carried out,with electron correlation effects taken into consideration.The relaxation of core and excited orbitals and configuration interaction are found to be crucial to creating the double vacancy states by single photo-absorption.The predominant decay paths for the double vacancy states turn out to be of the LLM Auger decay to 1s 2s22p53s(3p),KLL Auger decay to 1s 22s2p43s3p,and KLM Auger decay to 1s 22p63s(3p).They lead to further Auger decay,creating the neon ions of multiple charge states.For both double and single vacancy states the spectator type of Auger process is dominated in all the Auger decay processes.Theoretical Auger electron spectra are presented for further investigations,experimental and theoretical.
In a recent XUV photoabsorption spectrum of Cs Ⅲ ions by Cummings and O'Sullivan [2001 J. Phys. B 34 199], rather large linewidths were found for the 4d 9 5s 2 5p 6 4d 10 5s 2 5p 5 transition which are quite in disagreement with corresponding quasi-relativistic multiconfiguration Hartree-Fock (MCHF) calculation. In the present work, a detailed multiconfiguration Dirac-Fock study has been carried out to explore this discrepancy. Owing to the detailed consideration of electron correlation effects, some 'forbidden' Auger decay channels, such as 4d 10 5s 2 5p 3 5d and 4d 10 5s 0 5p 6 , would become 'open'. As a result, remarkable improvement of the linewidths has been obtained in our calculation. Furthermore, the theoretical Auger spectrum of the 4d 9 5s 2 5p 6 core-excited states of Cs Ⅲ ions is given in the present work.
This paper calculates the transition wavelengths and probabilities of the two-electron and one-photon (TEOP) transition from the (3s-1 1/24dj) J=1,2 to (3p-1 3/2 4s 1/2) J=1 and the (3p-1 1/2 4s 1/2) J=1 to (3d-1j4dj) J=1,2 for highly charged Ni-like ions with atomic number Z in the range 47≤Z≤92.In the calculations,the multi-configuration Dirac-Fock method and corresponding program packages GRASP92 and REOS99 were used,and the relativistic effects,correlation effects and relaxation effects were considered systematically.It is found that the TEOP transitions are very sensitive to the correlation of electrons,and the probabilities will be enhanced sharply in some special Z regions along the isoelectronic sequence.The present TEOP transition wavelengths are compared with the available data from some previous publications,good agreement is obtained.
