Inter-shell correlations in the formation of singly charged ions near the Ar L-shell ionisation threshold

The yield of singly charged ions is considered for inelastic fast-electron scattering. The densities of the generalised oscillator strengths are calculated in the single-electron approximation, taking account of the many-electron inter-shell correlations in the RPAE framework and out of it. It is demonstrated that a special type of inter-shell interaction of the electrons is responsible for this effect. This interaction arises as a consequence of the rearrangement of the core self-consistent field due to Auger-decay of the 2p 6 vacancy. Such interactions may be considered as a type of the so-called post-collision interaction and this permits us to achieve reasonable agreement with the existing experimental data.