Conjugate shake-up process of neon due toK-shell photoionization

Many-body perturbation theory is applied to the process of $K$-shell photoionization of Ne with the $2p\to 3s$ excitation. Absolute cross section of the process as well as the conjugate shake-up probability, i.e., the ratio to the simple $K$-shell photoionization cross section, are calculated as functions of the photon energy. The latter agrees very well with the available experimental data. The calculated probability is large (about 5%) near the threshold. The angular distribution of the ejected electron with respect to the photon polarization axis is also obtained in the case of the linearly polarized photon.