Xe $1s$ photoelectron spectra were measured at SPring-8, Japan. The core-hole lifetime broadening was found to be 9.6 eV, yielding a lifetime of $\sim 68$ as. The amount of radiative versus nonradiative decay was assessed by recording Auger LMM spectra below and above the $K$ edge. Below the $K$ edge, $L$ vacancies are produced only by direct photoionization, while above the $K$ edge some of these vacancies are mainly produced by $KL$ emission following $1s$ photoionization. Due to the dipole selection rule for x-ray emission, the dominant role of the $KL$ relaxation process is rather directly observed.

• Received 15 February 2017

DOI:https://doi.org/10.1103/PhysRevA.95.061402