No abstract

Inner-shell resonant absorption (IRA) effects were investigated on evolution dynamics of charge state distribution (CSD) in the interaction of ultraintense x-ray pulses with a neon atom. IRA is the physical origin of the large discrepancies found between theory and experiment at a photon energy of 1050 eV [L. Young et al., Nature (London) 466, 56 (2010)], where the rates of K-shell resonant absorption 1s → 4p of Ne 6+ and 1s → 3p of Ne 7+ are larger than the direct single-photon ionization rates by more than one order of magnitude, and hence IRA becomes the dominant absorption mechanism. Only when the IRA effects are properly taken into account can we correctly explain the observed CSD.

The detailed level-to-level single and double Auger decay rates of Kr 3d−1 hole states are investigated in the framework of the first and second perturbation theory implemented by distorted wave approximation with the balanced large-scale configuration interaction of the successive ions being taken into account. The branching ratios of cascade and direct double Auger decay to the total probability are predicted to be 16.5% and 16.1%, respectively, for Kr and 16.8% and 17.2% for Kr , resulting in total double branching ratios of 32.6% and 34.0% for the two levels of Kr 3d−1 hole. A comparison is made with the available experimental results on the branching ratio into triply charged ions and good agreement was found with the most recent published work. This work represents the first theoretical study to correctly explain the experimental measurements. The complete pathways were depicted by including the direct double Auger decay process. Compared with the Auger decay of Ar 2p−1, the fraction of the cascade double of Kr 3d−1 is dramatically enhanced yet that of direct double Auger processes is only slightly increased.

Radiative opacity of open-M-shell germanium plasmas in the L-shell photon energy region were investigated in detail by using a fully relativistic detailed level accounting approach. Among other physical effects such as relativistic and the interaction between fine-structure levels belonging to the same non-relativistic configuration and different configurations, particular attention is paid on the effect of autoionization resonance broadening on the L-shell absorption. The results show that for plasmas at present and past typical experimental conditions, line width due to autoionization resonance broadening dominate among all the physical broadening mechanisms including electron impact and Doppler broadenings. Such an effect is most pronounced for ions with just a few 2p-nd transition lines such as , while it is not so pronounced for complex ions such as Ge , where there are so many 2p-nd lines that line overlapping partly conceal the effect of autoionization resonance broadening. After taking the effect of autoionization resonance broadening into account, detailed comparisons are made with available experimental spectra at different physical conditions of different plasma temperatures and densities. The L-shell absorption is sensitive to the plasma temperature, especially in the 2p-3d excitation energy region. The potential of utlizing the relative shape and intensity of the 2p-3d spin-orbit splitting as temperature diagnostics is investigated.

Large-scale configuration interaction calculations were carried out to obtain the level-by-level autoionization (AI) rates and resonance widths of the inner-shell excited configurations for the open-M-shell germanium ions. Detailed results are presented for Ge5+ as an example. The dominant ionization channels of the autoionized levels 2p53/23s23p63d10 and 2p51/23s23p63d10 of Ge5+ were determined, and it is shown that the channel from level 3s23p6(3d−13/23d−15/2)4 contributes the largest fraction of AI widths of 0.195 and 0.188 eV to the total width of 0.577 and 0.544 eV, respectively, from all possible channels. For typical experimental plasmas at temperatures of several tens and hundreds of eV, the AI resonance broadening is the dominant mechanism among the Doppler, electron impact and natural lifetime broadenings. Among the physical effects such as relativistic and the interaction between fine-structure levels belonging to the same non-relativistic configuration and different configurations, particular attention is paid to the effect of AI resonance broadening on the L-shell absorption. Different features of the inner-shell absorption due to AI broadening are presented in detail for Ge5+, Ge10+ and Ge17+. The total AI widths of levels from the configuration of one 2p electron being excited to 3d orbital were systematically investigated for Ge6+–Ge21+. Except for Ge20+ and Ge21+, the AI widths of the open-M-shell germanium ions dominate over all other line broadening mechanisms.