Unexpectedly small intrashell L1-L3 vacancy transition rate in 62Sm

The individual decay channels of samarium L-subshell vacancy states were experimentally investigated by the synchrotron photoionization method. For the Coster-Kronig yield f₁₃, i.e., the relative contribution of the nonradiative L_1-L₃ channel to the total decay of L₁-vacancy states, the value f₁₃=0.19+/-0.03 was obtained. This is a surprisingly small value regarding both prediction from theory (e.g., f₁₃=0.32 according to Chen, Craseman, and Mark [Phys. Rev. A 24, 177 (1981)]) and extrapolation from neighboring elements (f₁₃~=0.32 for the elements with Z=72-74 according to our previous work [U. Werner and W. Jitschin, Phys. Rev. A 38, 4009 (1988)]).