Abstract
Semiclassical formulae are derived which describe the influence of the slowly receding photoelectron on the Auger decay of an inner-shell ionized atom. The usefulness of the formulae is demonstrated by their successful application to the quantitative analysis of two different 'post-collision interaction' phenomena. It is predicted that under certain conditions the 'post-collision interaction' will lead to observable interference effects which can then be analysed by the derived semiclassical formulae.