15min:

L. BORVAYEH, N. MOAZZEN-AHMADI, Department of Physics and Astronomy, University of Calgary, Calgary, AB T2N 1N4, CANADA; V.-M. HORNEMAN, Department of Physical Sciences, University of Oulu, PO Box 3000, Fin-90014, Oulu, Finland.

The far-infrared spectrum of ¹²CH₃¹³CH₃ is studied between 220-350 cm^-1 at an effective resolution of 0.004-0.005 cm^-1 using a Bruker IFS-120 HR . Observation of the torsional fundamental ₆ (289 cm^-1) and the torsional hot band 2 ₆- ₆ (255 cm^-1), together with the lowest frequency vibrational fundamental ₁₂ (821.5 cm^-1), also obtained with the same spectrometer at an effective resolution of 0.0025 cm^-1, gives information on the torsional stack of the ground vibrational state and that for v₁₂=1 state. The frequencies are analysed in terms of a 2-state fit to determine the torsion mediated Coriolis interactions between the torsional stacks. A comparison is made with a 2-state fit of similar data for ¹²CH₃¹²CH₃.