Calculation of Ion Charge State Distributions After Inner-Shell Ionization in Xe Atom

The vacancy cascades following initial inner-shell vacancies in single and multi-ionized atoms often lead to highly charged residual ions. The inner-shell vacancy produced by ionization processes may decay by either a radiative or non-radiative transition. In addition to the vacancy filling processes, there is an electron shake off process due to the change of core potential of the atom. In the calculation of vacancy cascades, the radiative (x-ray) and non-radiative (Auger and Coster-Kronig) branching ratios give valuable information on the de-excitation dynamics of an atom with inner-shell vacancy. The production of multi-charged ions yield by the Auger cascades following inner shell ionization of an atom has been studied both experimentally and theoretically. Multi-charged Xe ions following de-excitation of K-, L(1-), L(2,3-), M(1-), M(2,3-) and M(4,5) subshell vacancies are calculated using Monte-Carlo algorithm to simulate the vacancy cascade development. Fluorescence yield (radiative) and Auger, Coster- Kronig yield (non- radiative) are evaluated. The decay of K hole state through radiative transitions is found to be more probable than non-radiative transitions in the first step of de-excitation. On the other hand, the decay of L, M vacancies through non-radiative transitions are more probable. The K shell ionization in Xe atom mainly yields Xe(7+), Xe(8+), Xe(9+) and Xe(10+) ions, and the charged X(8+) ions are the highest. The main product from the L(1-) shell ionization is found to be Xe(8+) Xe(9+) ions, while the charged Xe(8+) ions predominate at L(2,3) hole states. The charged Xe(6+), Xe(7+) and Xe(8+) ions mainly yield from 3s(1/2) and 3p(1/2, 3/2) ionization, while Xe in 3d(3/2, 5/2) hole states mainly turns into Xe(4+) and Xe(5+) ions. The present results are found to agree well with the experimental data.