Method to evaluate empirical photoionisation cross-sections for L3 magnetic sub-states

A method to evaluate empirical values of L3 magnetic sub-state photoionisat ion cross-sections has been reported. Preliminarily, the method requires sc anning of the existing experimental data on L X-ray fluorescence (XRF) cros s-sections for energy dependence of L alpha /Ll cross-section ratio. After assuring the energy dependence of L alpha /Ll cross-section ratio, the rati o is used for the determination of the alignment parameter A2. Thus, the de termined A2 value, along with the available data on the sub-shell photoioni sation cross-sections sigma (Li) and the Coster-Kronig transition probabili ties fy, is used to evaluate magnetic sub-state photoionisation cross-secti ons sigma (Li)(m) for m = 3/2 and 1/2. The method has been used to evaluate L3 magnetic sub-state photoionisation cross-sections for four elements wit h Z greater than or equal to 82, from the measured L XRF cross-sections. To the best of our knowledge, until this date neither theoretical nor semiemp irical data on magnetic sub-state photoionisation cross-sections for these elements has been available, for comparison with such cross-section values and to establish the superiority of one data set over the others. (C) 2001 Elsevier Science Ltd. All rights reserved.