Resonant electron emission in Ti and TiO2

A direct electronic recombination process is observed following $3p$ excitation in both Ti and Ti${\mathrm{O}}_2$. In Ti this leads to resonant photoemission from the $3d$ valence levels at a photon energy 14 eV above the $3p$ threshold. In Ti${\mathrm{O}}_2$ the oxide valence-band emission is enhanced at the $3p$ resonance energy. This is the first observation of interatomic resonant photoemission in an oxide. The resonant electron emission is also observed in electronically excited Auger spectra.