Auger cascades in resonantly excited neon

Abstract

The Auger cascades following the resonant $1s\ensuremath{\rightarrow}np$ ($n=3,4$) excitation of neutral neon are studied theoretically. In contrast to previous investigations, we here model the complete cascade from the initially core-excited $1{s}^{\ensuremath{-}1}3p\phantom{\rule{0.16em}{0ex}}^{1}P_{1}$ and $1{s}^{\ensuremath{-}1}4p\phantom{\rule{0.16em}{0ex}}^{1}P_{1}$ levels of Ne up to the doubly ionized ${\mathrm{Ne}}^{2+}$ ions. Extensive multiconfiguration Dirac-Fock calculations are carried out, combined with a proper cascades model, to incorporate as many decay branches as possible, including all major single-electron shake-up and shake-down processes. We simulate the electron spectra and predict shake probabilities, ion yields, as well as the relative population of the intermediate and final states. Experimentally known level energies for neutral, singly, and doubly ionized neon are utilized whenever possible in order to improve the predictions. Most features from experiment can be reproduced with quite good agreement if a sufficiently large basis is taken into account. These simulations therefore demonstrate not only the required computational effort, but also that it is nowadays possible to predict whole Auger spectra of decay cascades, a central feature for further exploring electron coincidence maps as obtained at synchrotrons and free-electron lasers.