Torsional Line Splittings in the (ν4+ν8)−ν4 Hot Transitions of C2H6 between 1400 and 1510 cm−1
✍ Scribed by F. Lattanzi; C. di Lauro; M. Herman; J.Vander Auwera
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 139 KB
- Volume
- 216
- Category
- Article
- ISSN
- 0022-2852
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✦ Synopsis
A detailed investigation of the high-resolution infrared spectrum of ethane revealed the occurrence of features belonging to the hot perpendicular system (ν 4 + ν 8 ) -ν 4 between 1400 and 1510 cm -1 . Transition lines of the subbranches with K K from -7 to 4, exhibiting torsional splittings of several tenths of a cm -1 , were observed and measured in this region. The observed line splittings are strongly influenced by the interaction between the ν 4 + ν 8 and 2ν 4 + ν 12 states and change with the values of K K , depending on the zero-order energy separation of the interacting levels. We found by numerical extrapolation that splittings still occur far from resonance, showing that the intrinsic torsional splittings of the combining states ν 4 + ν 8 and ν 4 are quite different. We determined the intrinsic torsional splitting of ν 4 + ν 8 to be less than 0.083 cm -1 , compared with 0.236 cm -1 estimated for the ν 4 state. This result is in agreement with the expected effects of torsional Coriolis and head-tail coupling and is consistent with previous observations on vibrationally degenerate states of ethane-like molecules.