High‐resolution stimulated Raman spectrum of ethane (¹²C₂H₆) in the region of the CH symmetric stretching

Abstract

The high-resolution (ca. 0.008 cm-') stimulated Raman spectrum of the strongly perturbed C-H symmetric stretching region of 12C2H, at room temperature and at a rotational temperature of ca. 30 K, achieved in a free supersonic jet expansion chamber, is reported. The spectrum is tentatively analysed and assigned in terms of a simplified vihratiow-torsiornotation Hamiltonian. Besides the already known strong Fermi resonance, several Coriolis torsional interactions are identified as the major perturbations in this spectral region.

Weak Combination Bands in the 3-μm Region of Ethane

“…It, however, disagrees with the result of Lepard et al, 12 ϭ ϩ0.23 (18). The latter value, which was used in the recent literature (10,11), is different enough from the other one to significantly influence the present as well as our previous (21) vibrational assignments. Experimental evidence supports our choice.…”

Infrared Reflection−Absorption Spectra of C2H4 and C2H6 on Cu: Effect of Surface Roughness

“…For C 2 H 4 , the conditions are apparently good. The occurrence of E bands of the b 2g CH 2 wagging mode and the a g CH 2 -scissor and CC-stretch modes is explained by s-wave and d-wave 18 For the free molecule, the IR and the Raman activity of a mode is indicated by "IR" or "R", respectively; p and s denote directions of the IR dipole parallel and perpendicular to the CC axis, respectively. "pol."…”

“…Torsions a 1u are inactive; see also ref . “FR” indicates the Fermi-resonance effect that gives two lines . For the free molecule, the IR and the Raman activity of a mode is indicated by “IR” or “R”, respectively; p and s denote directions of the IR dipole parallel and perpendicular to the CC axis, respectively.…”

A simple model to simulate the Raman spectrum of methane in the range of 2800–3040 cm−1

“…The greatest difference was localized in the vicinity of the ν 1 peak of methane and was about 4% relative to its height (see Figure S4). It was found that the extracted ethane bands (Fermi‐coupled cluster of the ν 1 , 2ν 2 , 2ν 6 , 2ν 8 , 2ν 11 , and 2ν 12 vibrations 71,72 ) were narrower compared with the spectrum of pure ethane at the same pressure (see Figure S4). We suppose that the collisional broadening effect for the rotational–vibrational lines of C 2 H 6 perturbed by CH 4 is less than the effect of C 2 H 6 –C 2 H 6 collisions.…”