L1−L3Coster-Kronig yield for elements with70⩽Z⩽81

Abstract

The ${L}_{1}\text{\ensuremath{-}}{L}_{3}$ Coster-Kronig (CK) yield ${f}_{13}$ for the $_{70}\mathrm{Yb}$, $_{71}\mathrm{Lu}$, $_{74}\mathrm{W}$, $_{75}\mathrm{Re}$, $_{79}\mathrm{Au}$, $_{80}\mathrm{Hg}$, and $_{81}\mathrm{Tl}$ elements was deduced using measured intensities of the $L\ensuremath{\alpha}$ x rays emitted following decay of the ${L}_{i}$-subshell $(i=1,2,3)$ vacancies produced in widely different proportions by the $59.54\phantom{\rule{0.3em}{0ex}}\text{keV}$ $\ensuremath{\gamma}$ rays $({B}_{{L}_{1}}l{E}_{inc}l{B}_{K})$ and the $\text{Ge}∕\text{Se}∕\text{Rb}$ $K$ x rays $({B}_{{L}_{3}}l{E}_{K\ensuremath{\alpha}}l{B}_{{L}_{2}},{B}_{{L}_{1}∕{L}_{2}}l{E}_{K\ensuremath{\beta}}l{B}_{K})$; where ${\mathrm{B}}_{K∕Li}$ is the $K$-shell∕${L}_{i}$-subshell binding energy of the target element. An energy-dispersive x-ray fluorescence set up, involving photon sources consisting of a $^{241}\mathrm{Am}$ annular source in the direct and secondary excitation modes along with the $\text{Ge}∕\text{Se}∕\text{RbCl}$ secondary exciter and a $\text{Si}(\text{Li})$ detector, was used for the measurements. The measured ${f}_{13}$ yields for $_{70}\mathrm{Yb}$, $_{71}\mathrm{Lu}$, and $_{74}\mathrm{W}$ are found to agree with the values based on the relativistic Dirac-Hartree-Slater (RDHS) calculations, while those for $_{79}\mathrm{Au}$, $_{80}\mathrm{Hg}$, and $_{81}\mathrm{Tl}$ are lower by $\ensuremath{\sim}20%$. The measured ${f}_{13}$ yields exhibit a jump from 0.354(24) for $_{74}\mathrm{W}$ to 0.450(27) for $_{75}\mathrm{Re}$ compared to that from 0.352 to 0.640 as predicted by the RDHS calculations due to onset of the intense ${L}_{1}\text{\ensuremath{-}}{L}_{3}{M}_{5}$ CK transition.