Double Auger decay in atoms: Probability and angular distribution

Within many-body perturbation theory (MBPT), the correlated decay of an inner-shell vacancy, namely, the double Auger effect, is considered. Expressions for the amplitude and probabilities are obtained in the lowest order of MBPT. The approximate formulas, in particular the ‘‘shakeoff’’ model, are discussed. The calculations are performed for the 1${\mathit{s}}^{\mathrm{-}1}$→2${\mathit{s}}^{\mathrm{-}2}$2${\mathit{p}}^{\mathrm{-}1}$+${\mathit{q}}_1$+${\mathit{q}}_2$ transition in Ne. It is shown that the angular distribution of electrons ejected in the double Auger decay of an s hole is asymmetric, depending strongly on the angle of their relative motion.