Hyperfine-resolved high-resolution laser spectroscopy of 14NO2 radical in the 15885 cm−1 energy region

Abstract

Hyperfine-resolved high-resolution fluorescence excitation spectrum of the A˜2B2 ← X˜2A1 transition of 14NO2 radical in the 15870–15900 cm−1 energy region was observed, by crossing a jet-cooled molecular beam and an output of a single-mode dye laser at the right angles. We obtained the rotational assignments up to N′ = 11 for the Ka = 0 series and those up to N′ = 7 for the Ka = 1 series by analyzing the observed hyperfine structures and employing the combination differences, and determined the molecular constants of the upper vibronic level. Most of the Fermi contact interaction constants of the rotational levels of the upper vibronic level were found to range from 0.002 cm−1 to 0.004 cm−1. The (Ka′ = 0, N′ = 3, J′ = 3.5) level was found to be strongly perturbed, and we recognized some perturbers in the vicinity of the main rotational level. We concluded that the most plausible candidate of the perturbers in this region is the vibronic levels having almost pure A˜2B2 electronic state character.