l-Resonance Intensity Effects and Pressure Broadening of N2O at 17 μm

Abstract Absolute intensities of PR branch transitions in the three hotbands 2ν 2 f 2 ← ν 1 f 2 2ν 2 e 2 ← ν 1 e 2 and 2ν 0 e 2 ← ν 1 e 2 have been measured using high resolution spectra recorded with the McMath FTS at the National Solar Observatory in Kitt Peak, Arizona. The two latter bands show intensity perturbations mostly due to rotational l -type doubling while the hot band ending in the (02 2 f 0) state remains unperturbed. Based on mixing coefficients calculated from effective molecular constants, intensity perturbation factors were calculated which are shown to be equivalent to a quadratic term used in the Herman–Wallis factor expression. As part of the intensity retrieval, self-, N 2 -, and He-broadening coefficients of N 2 O were determined in the ν 2 fundamental and the three hot bands. The linewidths reported in this study have been combined with the best available literature data from other bands to retrieve temperature dependent relaxation rates due to rotationally inelastic collision based on a scaling law.