Subnatural linewidths in the Kr M5N2,3N2,3 and Xe N5O2,3O2,3 resonant Auger spectra

The line sharpening effect, one of the characteristics of the Auger resonant Raman effect when the bandwidth of exciting photons is smaller than the lifetime widths of the corresponding core levels, has been observed with clarity for the first time. The kinetic energies of the resonant Auger lines following the 3d->5p and 4d->6p excitations in Kr and Xe, respectively, display also linear dispersion when photon energy is scanned over the resonances.