The band of ethane: A global frequency analysis of data from the four lowest vibrational states

High resolution infrared spectrum and global analysis of ν5, ν12, and ν12+ν6−ν6 in CH3SiH3

“…Similar behaviour was observed for CH 3 CH 3 [7,8], both with respect to the number and the magnitude of the molecular parameters. For example, for methyl silane, a total of 33 parameters were used here to characterize the m 12 diagonal terms, as compared to 25 for the lowest lying degenerate mode in ethane [8]. These numbers are closer together than might appear at first glance, because 5 of the CH 3 SiH 3 parameters are forbidden in CH 3 CH 3 by symmetry.…”

“…A four state analysis was carried out [7,8], involving the gs and one non-degenerate mode m 3 , as well as two degenerate modes m 9 and m 12 . Four resonant interactions between torsional stacks in the different skeletal modes were identified, including two that involve levels in m 9 with one quantum of torsion m 4 excited.…”

Toward the understanding of the high resolution infrared spectrum of C2H6 near 3.3μm

“…Numerical rotational analyses of the degenerate m 9 fundamental occurring in the first region near 822 cm À1 , including torsional splittings caused by the interaction with the torsional system 3m 4 (m 4 near 289 cm À1 is the torsional mode of vibration), became available early in the 1980s [1][2][3]. However, a very accurate analysis of this region has been performed only recently [4]: it included the m 9 band, the associated hot transitions (m 4 + m 9 ) À m 4 , the infrared inactive C-C stretching fundamental m 3 (near 995 cm À1 , activated by perturbations at resonance), the m 12 -m 9 difference band near 385 cm À1 (m 12 is the symmetric CH 3 rock, near 1195 cm À1 ), and the torsional bands m 4 , 2m 4 -m 4 and 3m 4 . The second region is probably the most studied infrared region of ethane.…”

The ν4, ν9, ν10 and ν6+ν11 bands of 12CH313CH3 between 1345 and 1557cm−1

“…(6) shows that the torsional shifts versus k À ' follow three sinusoidal patterns, for the three values of r. If the two internal rotors are identical, then q = 1/2, see Eq.…”