Weak Combination Bands in the 3-μm Region of Ethane

Laboratory Studies on the Irradiation of Methane in Interstellar, Cometary, and Solar System Ices

“…b Not the major contributing species to the band (see text for details). c Assignment supported by work from Nakamoto (1997) as well as Hepp & Herman (1999). d Assignment based on calculated band positions of these species (see Appendix).…”

“…As most of these features have been previously identified in irradiation experiments on methane ice, we shall only discuss those that are reported for the first time. In regards to ethane (X 1 A 1g ), the bands at 2941 and 2915 cm À1 are tentatively assigned to the infrared active combination bands arising from the combination of the v 8 þ v 11 modes (E u E g ¼ A 1u È A 2u È E u ) allowing two infrared active bands ( Nakamoto 1997;Hepp & Herman 1999); the relative intensities of these bands of about 4 : 1 is the same as in pure ethane samples from our laboratory data ( Fig. 3c).…”

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

“…Its effects are clearly seen in Fig. 3: the relative positions of the J-pairs (19,20) and (21,22) are inverted.…”

“…3 for r Q 5 and r Q 6 . We explain this perturbation as resulting from a l-type interaction with Dl = ±2 and Dk = Ç1 [l(2, À1) interaction] between the m 7 state and the degenerate component of the combination state m 8 + m 11 , identified by Hepp and Herman [19] using a slit jet cooled Fourier transform spectrum. Indeed, the vibrational frequency and Coriolis coefficient of that state are such that the l(2, À1)-resonance with m 7 can be predicted to occur precisely where observed, that is for K 00 DK between 5 and 6.…”

Titan at 3 microns: Newly identified spectral features and an improved analysis of haze opacity

“…Ethane, having twelve fundamentals (seven of which are not infrared active), gives rise to complex spectra that can take years to characterize, as demonstrated by the recent work of Lattanzi et al (2008) at 14 μm. For the band of C 2 H 6 near 3.07 μm (3258 cm −1 ) identified as ν 4 + ν 10 by Hepp and Herman (1999), we directly adopted the line list of Kim et al (2006). Note that the band designation, ν 3 + ν 9 + ν 11 , used by Kim et al (2006) should be replaced by ν 4 + ν 10 .…”