N. MOAZZEN-AHMADI, J. NOROOZ OLIAEE, Department of Physics and Astronomy, University of Calgary, 2500 University Dr., N.W., Calgary, Alberta T2N 1N4, Canada; V.-M. HORNEMAN, Department of Physical Sciences, University of Oulu, P.O. Box 3000, Fin-90014 Oulu, Finland.
High-resolution infrared spectra of the 12+ 6- 6 (around 820 cm-1) and 11- 12 (around 370 cm-1) bands of 12CH313CH3 are assigned. Frequencies from these bands together with data from the 12 and 5 fundamentals and the torsional bands were analysed in a 4-state fit to determine the torsion mediated Coriolis and Fermi interactions. As compared to normal ethane this lower symmetry isotopologue shows more complicated vibrational couplings. The combined data set includes more than 6800 frequencies and was fitted to within experimental accuracy using a 77-parameter Hamiltonian. The first determination of molecular parameters for the 11 state of 12CH313CH3 has been made and using this Hamiltonian we have provided lower state energies and partition functions between 100 and 330 K in increment of 10 K for planetary data analysis. A comparison with a 4-state fit of similar data for 12CH312CH3 will be made.