ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
The far-infrared spectrum of gaseous CD3CD3 has been measured in the region of the torsional fundamental under relatively large pressure-path length conditions. The observations were made using a modified Bomem spectrometer at a resolution of 0.016 cm−1, an absorption path of 20 m, and a gas temperature and pressure of 168 K and 80 Torr, respectively. The prominent features of the spectrum are the P, Q, and R branches of the torsional fundamental (v4=1←0) and the Q branch of the first torsional overtone (v4=2←1). The P and R branches of the fundamental consist of peaks about 0.2 cm−1 wide due to unresolved structure. In addition, a very high resolution (0.0014 cm−1) spectrum of the lowest lying degenerate fundamental ν9 of CD3CD3 was obtained. From the combined intensity and frequency analyses of the far-infrared spectrum and 442 lower state combination differences in ν9 and its associated hot band ν9+ν4−ν4, the effective leading coefficients V˜3=989.10(68) cm−1 and V˜6=9.47(29) cm−1 in the Fourier expansion of the hindering potential were determined. The rotational constant B was found to be 13 802.658(39) MHz and four distortion parameters were obtained. The torsional dipole constants μ⊥ and μ(parallel)−μ⊥ were determined to be 7.41(74) and −19.9(2.0) μD, respectively. The experimental values of μ⊥ and μ(parallel)−μ⊥ are shown to be in good agreement with values calculated from theoretical expressions. The shape of the torsional bands can be reproduced in detail with the model adopted here.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.459862
