Using a Si(Li) x-ray spectrometer, we have measured the respective fractions of $L_1,$ $L_2,$ and $L_3$ x rays in the L x-ray spectrum emitted in the ${}^{157}{\mathrm{T}\mathrm{b}-}^{157}\mathrm{Gd}$ electron-capture decay. Using, in addition, our previously measured value for the ratio of L and K x rays, we deduce values for the fluorescence and Coster-Kronig yields of the $L_1$ subshell. These are ${\omega }_1=0.101\mathrm{}\pm 0.005,$ $f_{12}=0.166\mathrm{}\pm 0.020,$ and $f_{13}=0.287\mathrm{}\pm \mathrm{0.014.}$ The $f_{12}$ and $f_{13}$ values are significantly below the predictions of the independent-particle model (IPM). The deduced $L_1$ level width of 3.7 eV is also significantly below the IPM width of 4.6 eV.

• Received 6 May 1998

DOI:https://doi.org/10.1103/PhysRevA.58.3537