High-resolution spectra and analysis of the hot bands of the v₂vibration of CF₃Cl (v₂+ v_n- v_n,n= 3, 5, 6)

Abstract

A detailed analysis is reported of high resolution I.R. spectra of CF3C1 (Freon 13, chlorotrifluoromethane) in the 750-800cm -1 range obtained by Fourier transform and diode laser spectroscopy. A comparison is made between hot-band transitions starting from a non-degenerate vibrational level (V 2 "~ ' i~ 3 --lP3) and those from two-fold degenerate levels (v 2 + v 5 -v 5 and v2 + v6 -v6). For the latter the effect of vibrational excitation on the Coriolis constant A( has been observed. The rotational analysis of the v2 + v6 -v6 band of CF33SC1 has been performed in the P-and R-branches up to J = 32 and 34 respectively. Rotational/-doubling in both v 6 and v 2 + v 6 state causes a splitting of the kl = 1 transitions and observable shifts in transitions with other (low) kl. A least-squares fit of more than 500 lines yielded molecular constants for the v 2 + v 6 state.

Supersonic free-jet quantum cascade laser measurements of ν4 for CF335Cl and CF337Cl and FTS measurements from 400 to 1260cm−1

“…Because the data were much better and more extensive for the CF 3 35 Cl species, the values of DD J , DD JK , and DD K were assumed to be the same for the two isotopomers as well as for the hot band. The resulting constants are given in Table 8 and agree with the earlier work of Nencini et al [28] and Bürger et al [19]. The analysis of the hot band m 2 + m 3 -m 3 was combined with the analysis of the difference band m 1 -m 3 because they both have the same lower state and contribute to the determination of the constants for m 3 .…”

“…The measurements given by Baldacchini et al [26] and by Nencini et al [28] were useful for verifying the assignments we found for both isotopic species. The present work used a gas sample that contained the natural abundance of isotopes and so allowed us to determine an accurate value for the isotopic shift for m 2 .…”

“…The m 2 band of CF 3 35 Cl was studied along with several associated hot bands [19,26,28]. The m 5 band of CF 3 35 Cl was first measured with low resolution [12] although somewhat improved measurements were later made [21].…”