Measurement of L subshell yields of La by means of coincidence and critical absorption

The L subshell yields ω 2 , ω 3 , and f 23 have been measured for Z = 57 by observation of the X rays of 139 Ce employing a method combining coincidence and critical absorption. The results for ω 2 (0.112 ± 0.009) and ω 3 (0.092 ± 0.008) are in fairly satisfactory agreement with theory but f 23 (0.21 ± 0.02), as has been shown to be the case at other Z values, exceeds theoretical predictions.