The infrared spectrum and molecular constants of CO₂ in the 2 μm region

Abstract

The spectrum of CO2 has been recorded in the 2 μm region using high resolution Fourier transform spectroscopy. The effective constants have been determined with good accuracy for the (2001, 0401) and (211l, 0511) triads and the 0112–0000 transition. In addition, the vibrational energy of the (3001, 0601)1V level, previously given, has been corrected. The Coriolis resonance, strongly perturbing the (211e1, 051e1)m and (4000, 0800)n levels, has been studied.

Near infrared spectroscopy of carbon dioxide I. 16O12C16O line positions

“…The spectroscopic constants determined in the present study are compared with those from previous studies in Table 6. The G v values from the Arcas et al fits [19], and thus the R92 values, are systematically 2 Â 10 À4 cm À1 higher than the present values, and the difference is most likely due to changes in the calibration standards, given the good overall agreement between the rotational and distortion constants. However, the direct comparison of 20011 00001 line positions given in Fig.…”

“…3, the spectrum between 4700 and 5200 cm À1 is dominated by the Table 6 shows that Arcas et al obtained RMS errors of 9.9 Â 10 À5 , 10.9 Â 10 À5 , and 5.0 Â 10 À5 cm À1 for fits to these same bands [19]. The constants presented in Table 2 also predict accurate line positions for higher J transitions.…”

“…The hot band vibrational energies are compared in Table 7. The G v values reported for Arcas et al [19] are calculated from G 0 À Bl 2 for consistent comparison. We note that Arcas et al fit the vibrational origins for the e and f components of each upper state independently.…”

“…Fits to the hot bands yielded RMS errors <2 Â 10 À4 cm À1 for all of the e-and f -components with the exception of 21113e. The perturbation of this state is known and has been discussed by Arcas et al [19] and Bailly et al [36]. Since it is not possible to provide an accurate description of the 21113e 01101e line positions using the simple spectroscopic parameters G v , B v , D v , and H v , detailed reinvestigation of this problem is deferred for the future.…”

“…The carbon dioxide line parameters were predicted via the direct numerical diagonalization (DND) method [17], and then bands were recomputed if good experimental data were available. Line positions for the NIR bands were determined from the laboratory measurements of Maillard et al [18] and Arcas et al [19] recorded in the early 1980s. Many weaker bands were not observed in the laboratory, and the recommended spectroscopic parameters were taken from MandinÕs spectra of Venus recorded in 1977 [20].…”