Beyond the shake process

A new theoretical model for electron transition probability accompanying inner-shell vacancy production is presented. In this model, both the existence of the inner-shell vacancy and the Coulomb interaction between the ejected electron and atomic electrons are taken into consideration. The electron transition probability is expressed as the sum of the conventional shake process and multipole transitions due to the Coulomb interaction between electrons. The excitation probabilities for 2p electrons in Ne accompanying 1s-shell photoionization are calculated and the contribution of the Coulomb interaction terms is discussed