Ionization Potential and Absorption Coefficients of Nitrogen Dioxide

Abstract

Absorption coefficients of NO₂ were measured at a number of wavelengths in the spectral region 1080–2700 A with a resolution of 0.2 A by a photoelectric method. Several bands observed in the region 1080–1200 A fitted a Rydberg series, and its convergence limit at 11.62 ev was interpreted as the second ionization potential of NO₂. The first ionization potential was found to be 9.78 ev by the photoionization method. The ionization continuum showed a break at 10.83 ev which may be due to a probable dissociative‐ionization process. Several other electronic transitions corresponding to discrete and continuous absorption are discussed.