M4,5N4,5XAuger electron spectra of iodine and xenon. Many-body effects

High-resolution $M_{4,5}{N}_{2,3}{N}_{4,5}$, $M_{4,5}{N}_{4,5}{N}_{4,5}$, and $M_{4,5}{N}_{4,5}O$ Auger spectra from ${\mathrm{I}}_2$ vapor and from Xe gas have been measured using electron-beam excitation. In order to reduce satellite backgrounds, the $M_{4,5}{N}_{4,5}{N}_{4,5}$ spectra were also taken using primary-beam energies just below the core-ionization energy of the $M_3$ levels of iodine and xenon. The relative line energies and intensities for all of the xenon spectra and for iodine $M_{4,5}{N}_{4,5}{N}_{4,5}$ spectra have been calculated in the mixed-coupling scheme. The agreement between theory and experiment is excellent for the $M_{4,5}{N}_{4,5}{N}_{4,5}$ spectra of both xenon and iodine. The agreement for the xenon $M_{4,5}{N}_{2,3}{N}_{4,5}$ spectrum is less good, but is close enough to indicate the approximate validity of the independent-electron model. This result is in contrast to that for one-hole states involving the $N_{2,3}$ shell; such a model fails completely to account for the xenon $4p$ photoemission spectrum. The independent-electron model will not account for the $M_{4,5}{N}_{2,3}{N}_{4,5}$ spectrum of iodine. Reasons for the success of this model for xenon and its failure for iodine are presented. The observed inherent linewidths of the Auger lines are considerably broader in molecular iodine than in xenon. The photoelectron spectra and core-ionization energies of the $3d$, $4s$, $4p$, $4d$, $5s$, and $5p$ levels of ${\mathrm{I}}_2$ have been measured. The role of extra-atomic relaxation in the observed Auger energies is discussed.