Luminescence of Solids Excited by Surface Recombination of Atoms. V. Quantitative Dependence of Luminescence Response on Oxygen- and Nitrogen-Atom Densities

Abstract

The quantitative relationship between luminescence response and atom density was investigated for the lumophor CaO:Sb:Cl excited by surface recombination of nitrogen or oxygen atoms. Atom densities were determined by electron spin resonance employing molecular oxygen as a standard of spin density. Luminescence response is essentially linearly proportional to nitrogen-atom density for total nitrogen pressures of 0.007 to 0.29 Torr. Luminescence response to oxygen atoms, determined at a total oxygen pressure of 0.016 Torr, is linearly proportional to oxygen-atom density when account is taken of the decreased response caused by oxygen-atom exposure. However, for certain operating conditions of the discharge, enhanced luminescence response occurred at oxygen-atom densities less than 3×1013 atom/cc; also, no significant decrease of response occurred with exposure to oxygen atoms at densities less than 0.4×1013 atom/cc. The enhanced response and the absence of a decreased response upon continued exposure are attributed to electronically excited oxygen species, probably O(1D) or O(1S). Equal densities of nitrogen and oxygen atoms produced about the same luminescence response.