Photon-stimulated desorption of O(P-3) and NO((2)Pi) from NaNO3 single crystals

The 193-nm photon-stimulated desorption (PSD) of O(P-3) and NO((II)-I-2) from NaNO3 crystals was detected via state-resolved laser ionization spectroscopy. Yields of these dissociation fragments show a one-photon dependence upon the 193-nm laser fluence, with no observable thresholds, down to similar to 1 mu J/cm(2). The O(P-3) J-state distribution is nonthermal, and the O(P-3) and NO((II)-I-2) velocity distributions are bimodal, with thermal and nonthermal components, consistent with near-surface dissociation events. We discuss the results in terms of exciton creation and fragment production via dissociative anionic pathways. We also discuss the similarities between our experimental results and those of alkali halide PSD studies, and suggest that the exciton-mediated PSD mechanism developed for alkali halides may be extended to apply generally to insulators with polyatomic anions.