Knowledge Bank

The infrared spectrum of the $\nu 9$ band of ethane has been recorded with a resolution of $0.004cm-1$ using a Fourier transform spectrometer. In addition, twelve Q-branches ranging from have been measured with a diode laser spectrometer capable of Doppler limited resolution ($0.002cm-1$). The line splittings reported by Flicker et $al.1$, in the Q-branches of this band have been verified and observed in the P- and R-branches as well. Quantum number assignments have been made with the aid of combination differences calculated from well determined ground state $constants.2$ Nuclear spin statistics clearly show that the individual transitions are split into their two torsional components even though torsional splitting for this band would be expected to be un-resolvable. The observed splitting is J dependent and varies from K to K. The large splitting observed probably results from an interaction of the $\nu 9$ state with the components of the v - 3 level of the torsional vibration. Preliminary results will be reported. The most recent theoretical work on this molecule was presented by Hougen $\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$ and some of the above studies were undertaken as a sequel to the recommendations in his paper.