Anomalous Lγ2,3x-ray emission spectrum of Xe

The L${\gamma }_2$,3(2${\mathrm{s}}^{\mathrm{-}1}$→4${\mathrm{p}}^{\mathrm{-}1}$) x-ray emission spectrum of gaseous xenon was measured in fluorescence with a high-resolution vacuum double-crystal spectrometer. The spectrum was also calculated by the Green’s-function method. The agreement is excellent. It is shown that the spectrum can be interpreted essentially in terms of the spectral function of the 4p hole. The effects of the initial 2s-hole state on the final 4p-hole state are small. The spectrum shows that the quasiparticle picture of a 4p hole in xenon breaks down because of strong 4$p^{\mathrm{-}1}$⇆4$d^{\mathrm{-}2}$4(n,ɛ)f super-Coster-Kronig processes.