Irregularity of Autoionizing Rydberg Series in Photoionization Leading to the Si3+ 3l States from the Mg-Like Si2+ Ions

Abstract

We report the theoretical photoionization cross sections in the low energy region for Mg-like Si 2+ ion, with arousing desire for experiments. With the advent of third-generation synchrotron radiation sources, it is expected to study for this ionic system using merged-beam technique. Since the Mg-like Si 2+ ions are expected to be admixed with the ground-state and several low-lying excited-states, we have calculated the photoionization cross sections from the initial ground-state 3 s 2 1 S , and the excited-states 3 s 3 p 1,3 P , 3 s 3 d 1,3 D , and 3 s 4 s 1,3 S of Mg-like Si 2+ ion. For these calculations, we have used a most elaborate noniterative eigenchannel R -matrix method. We briefly discuss the results for autoionizing resonances and interlopers in the structure of photoionization cross sections, and compare with the previous results of Opacity Project.