An electron-ion coincidence spectroscopy study of ion desorption induced by core-electron transitions of surfaces

Ion desorption induced by core-electron transitions is studied for various surfaces by electron-ion coincidence spectroscopy combined with synchrotron radiation. In a study of F+ desorption from Si(100) terminated by fluorine using photoelectron photoion coincidence spectroscopy, the site-selective F+ desorption is directly verified; that is, F+ desorption is induced by Si 2p photoionizations at the =SiF, =SiF2, and -SiF3 sites. An Auger electron photoion coincidence study of a CaF2(111) film epitaxially grown on a Si(l ll) surface also presents direct evidence of F+ desorption, in this case in duced by F Is surface core exciton. These investigations demonstrate that e lectron-ion coincidence spectroscopy combined with synchrotron radiation is a powerful tool for studying ion desorption induced by core-electron excit ations.