Photoelectron emission studies of cleaved and excimer laser irradiated single-crystal surfaces of NaNO3 and NaNO2

Inorganic nitrates are susceptible to radiation damage, including ultraviol et (UV) laser irradiation. We present a monochromatized X-ray photoelectron spectroscopy (XPS) and He II (40.8 eV) ultraviolet photoemission spectrosc opy (UPS) study of melt-grown single-crystal NaNO3 and NaNO2 cleaved and ex cimer laser irradiated surfaces. Our results show that the changes observed in the NaNO3 spectra due to both X-ray and UV excimer laser irradiation ar e consistent with decomposition initiated by the pi-->pi* transition in the NO3- anion. Furthermore, we find very similar decomposition products for b oth X-ray and UV excimer laser irradiated surfaces, which mainly include so dium nitrite and sodium peroxide. Finally, direct comparison of our experim ental UPS and XPS valence-band electron-energy distributions with the calcu lated total density of states shows good agreement between theory and exper iment for both NaNO3 and NaNO2. (C) 1999 Elsevier Science B.V. All rights r eserved.