Abstract
Post collision interaction (PCI), usually considered as a threshold effect, is shown to persist at any non-relativistic impact energy in non-coincident particle impact experiments. As a result Auger lines obtained from these experiments are generally shifted in energy by an amount of the order of Gamma /(EB/R)12/, where Gamma and EB are the level width and binding energy, respectively, of the initial inner-shell hole. This effect has been neglected in the past; its implications are discussed.