Absorption cross-sections and pressure broadening of rotational lines in the 3ν3 band of N2O determined by diode laser cavity ring-down spectroscopy

Diode laser cavity ring-down spectroscopy (CRDS) has been used to measure rotational line intensities and air pressure broadening coefficients for the 3ν3 (N–N stretching) vibrational overtone band of N2O. The line intensity measurements are in quantitative agreement with previously reported Fourier transform spectroscopy results [J. Mol. Spectrosc. 197 (1999) 158]. The air pressure broadening coefficients increase from 0.086 ± 0.015 cm−1 atm−1 for the P(34) line to 0.139 ± 0.010 cm−1 atm−1 for the P(3) line, and are greater than values reported for other ro-vibrational bands of N2O observed at lower frequencies. The effects of pressure broadening on line-centre absorption cross-sections, and thus for the sensitivity of CRDS detection of N2O using narrow bandwidth near-IR lasers are quantified.