We report photon-stimulated desorption (PSD) of ions by the same core-hole Auger-decay mechanism observed in electron-stimulated desorption (ESD). Ions desorbed by synchrotron radiation were identified by time-of-flight mass spectroscopy. The thresholds for the PSD and ESD of ${\mathrm{H}}^{+}$, O${\mathrm{H}}^{+}$, and ${\mathrm{F}}^{+}$ from Ti${\mathrm{O}}_2$ are identical. The PSD excitation spectra consists of sharp peaks, compared to broad steps in ESD. PSD is shown to be a powerful surface probe with the potential of providing unique information on bonding sites.

• Received 9 February 1979

DOI:https://doi.org/10.1103/PhysRevLett.43.300