A many-body theory of the electron-ion coincidence spectroscopy spectra of the O+ ion desorption from TiO2(1Â 1Â 0) surface upon the Ti or O core-electron photoemission

Using the charge transfer (CT) core-hole screening model we analyzed the photoelectron-photoion coincidence spectroscopy (PEPICS) spectra of the O+ ion desorption from TiO2(1 1 0) surface measured in coincidence with the Ti or O core-electron photoemission. The present theory predicts well the ratio of the PEPICS spectral intensity measured in coincidence with the Ti core photoelectron spectroscopy (PES) satellite to that with the Ti core PES main line. In contrast to the Knotek and Feibelman (KF) mechanism the three localized O 2p holes created by CT Ti core-hole screening outlast the desorption so that the O+ ion desorbs from TiO2(1 1 0) surface upon the Ti core-electron ionization. The O 1s PES satellite creates three localized O holes by the O KV-L1VV spectator Auger decay, while the O 1s PES main line creates three localized O holes by the O K-VVV and K-L1VV Auger shakeup decay. As the Auger shakeup decay is very small compared to the spectator Auger decay, the O+ ion desorption yield in coincidence with the O 1s PES shakeup satellite is much enhanced compared to that with the O 1s PES main line.