Core-exciton–induced desorption from MgO

Core-exciton-induced desorption of ${\mathrm{O}}^{+}$ and ${\mathrm{H}}^{+}$ from MgO(100) and MgO(111) has been observed using photon excitation energies spanning the O K edge. Electron-yield data from partially oxidized Mg implies that these states are localized in the near-surface region. ${\mathrm{O}}^{+}$ and ${\mathrm{H}}^{+}$ desorption results from the decay of different O core-exciton states as well as the states produced by interband transitions. The O excitonic levels are interpreted in terms of their related atomic origin.