Post-Collision Interaction in the SeleniumL2M4,5M4,5Auger Spectrum Following Photoionization

The $L_{2,3}{M}_{4,5}{M}_{4,5}$ Auger spectrum of selenium in a variety of compounds has been measured following near-threshold photoionization of the $2p_{\frac{1}{2}}$ level by monochromatic Al $K{\alpha }_{1,2}$ radiation. The energy difference between the $L_2{M}_{4,5}{M}_{4,5}$ and the $L_3{M}_{4,5}{M}_{4,5}$ Auger peaks was observed to increase by as much as 1.1±0.1 eV as the $2p_{\frac{1}{2}}$ binding energy approached to within 1.1 eV of the ionization threshold. The energy shifts are compared with the predictions of a semiclassical analysis by Niehaus which takes into consideration the influence of the Coulomb field of the slow photoelectron on the Auger process.