Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8039079 | Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms | 2018 | 8 Pages |
Abstract
The Li (iâ¯=â¯1-3) subshell integral X-ray fluorescence (XRF) cross sections have been measured for 17 elements with 33â¯â¤â¯Zâ¯â¤â¯51 following photoionization by the Mn K X-rays (EKαβâ¯=â¯5.96â¯keV). The Li (iâ¯=â¯1-3) subshell X-rays were measured using a low-energy Ge (LEGe) detector at an emission angle, Ïâ¯=â¯125°, where angle-dependent emission effects, if any, are nullified as P2(cosâ¯Ï)â¯â¼â¯0. The XRF cross sections were interpreted in terms of available sets of theoretical Li (iâ¯=â¯1-3) subshell photoionization cross sections, radiative transition probabilities, and the atomic vacancy decay parameters, namely, fluorescence (Ïi) and Coster-Kronig (fij) yields. A set of L1 subshell fluorescence (Ï1) yields was deduced for the elements with 37â¯â¤â¯Zâ¯â¤â¯51 from the present measured Lγ2,3,(4) [L1-N2,3(O2,3)] XRF cross sections. The Ï1 values exhibit jumps at Zâ¯=â¯40 and 49, which are identified to be due to cut-off of the L1L2M4,5 and L1L3M4,5 Coster-Kronig (CK) transitions predicted by calculations based on relativistic Dirac-Hartree-Slater (RDHS) model. However, the measured Ï1 values are found to differ considerably from those based on the RDHS model calculations for the elements below Zâ¯=â¯50. The pronounced discrepancies between measured and theoretical Ï1 values are likely to be due to overestimation of the L1-L2,3M4,5 CK transition rates by a factor ofâ¯â¼2-3. Our experiential results demand consideration of extra-atomic relaxation from the solid-state effects and exchange splitting in many-body theoretical calculations of the low-energy CK transitions.
Keywords
Related Topics
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Authors
Heena Duggal, Veena Sharma, H.S. Kainth, Sanjeev Kumar, J.S. Shahi, D. Mehta,