Line strengths of 12C16O2: 4550–7000cm−1

Line positions and strengths of 12 C 16 O 2 were measured between 4550 and 7000 cm −1 using near infrared absorption spectra recorded at 0.01–0.013 cm −1 resolution with the McMath-Pierce Fourier transform spectrometer located at the National Solar Observatory at Kitt Peak, Arizona. These were retrieved from 42 laboratory spectra obtained at room temperature with five absorption cells having various optical path lengths (from 0.1 to 409 m) filled with natural and enriched samples of CO 2 at pressures ranging from 2 to 581 Torr. In all, band strengths and Herman–Wallis-like F -factor coefficients were determined for 58 vibration–rotation bands from the least-squares fits of over 2100 unblended line strengths; strengths of 34 of these bands had not been previously reported. Band strengths in natural abundance generally ranged from 3.30 × 10 −20 to 2.8 × 10 −25 cm −1 /molecule cm −2 at 296 K. It was found that the high J transitions ( J ′ ⩾ 61) of the 20012 ← 00001 band centered at 4977.8347 cm −1 are perturbed, affecting both measured positions and strengths. Two other interacting bands, 21113e ← 01101e and 40002e ← 01101e, were also analyzed using degenerate perturbation theory. Comparisons with corresponding values from the literature indicate that absolute accuracies better than 1% and precisions of 0.5% were achieved for the strongest bands.