Infrared line intensity measurements in the v = 0–1 band of the ClO radical

Abstract

Line intensities of the ClO radical in the fundamental vibrational band, v = 0–1, have been measured using a high‐resolution Fourier transform spectrometer coupled to a long path length absorption cell. The ClO infrared absorption spectra were recorded at 0.004 cm−1 unapodized resolution in 50 coadded scans at total pressures less than or equal to 0.4 torr, He buffer gas. Spectra were recorded at calibrated [ClO] over the range 4 × 1012 to 1.4 × 1013 molecule cm−3, using two different chemical sources of ClO: Cl + O3 and NO + OClO. The band intensity was measured as S = 9.68 ± 1.45 cm−2 atm−1 (95% confidence level) at 296 K, which is in agreement with a recent ClO band intensity determination using the concentration independent Herman‐Wallis method of band intensity analysis (Burkholder et al, 1987a). This value of the ClO band intensity is a factor of 2 greater than the value recently reported by Kostiuk et al. (1986). A N2 collisional broadening coefficient of γ0 = 0.093 ± 0.018 cm−1 atm−1 (95% confidence level) was determined from spectra recorded with 10 torr N2 added. A source of systematic error in the use of the Cl + O3 reaction as a quantitative source of ClO radicals is discussed.