Valence Auger and X-ray participator and spectator processes for neon and argon atoms

The rates of decay, both radiative and non-radiative, have been calculated for the valence shake-up states (vs, vp)nl of Ne(v = 2) and Ar(v = 3) for the five lowest n values. The various decay channels are discussed and trends for large n are examined. The calculations are performed at the single-configuration non-relativistic Hartree-Fock level. Inner-valence and valence-multiplet Auger channels are shown to be completely dominant, with maximum fluorescence yields of 2.7% in Ne and 0.2% in Ar. The total decay rates can be larger than the corresponding atomic K-shell rates for certain states, an extreme example being the Ar (3s, 3p)(¹P)3d(²P) rate of 0.148 au. The calculated widths are shown to be consistent with the experimental results of Svensson et al (1988). The valence-multiplet participator Auger transition is a mode of decay involving a change of multiplet state for the same initial and final two-hole valence configuration, and has been shown to account for the difference in width between certain photoelectron satellites in Ne. The experimental spectrum of Becker et al (1989) is discussed in the light of present results. The valence decay mechanisms identified are expected to have general applicability to light atoms and to molecules containing first or second row atoms.