Knowledge Bank

The far-infrared spectrum of $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}$CH$\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$$\mathrm{<mrow\; data-mjx-texclass="ORD">13</mrow>}$CH$\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$ is studied between $220-350$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ at an effective resolution of $0.004-0.005$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ using a Bruker IFS-120 HR . Observation of the torsional fundamental $\nu 6$ ($289$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$) and the torsional hot band $2\nu 6-\nu 6$ ($255$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$), together with the lowest frequency vibrational fundamental $\nu 12$ ($821.5$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$), also obtained with the same spectrometer at an effective resolution of $0.0025$ cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$, gives information on the torsional stack of the ground vibrational state and that for $v12=1$ state. The frequencies are analysed in terms of a 2-state fit to determine the torsion mediated Coriolis interactions between the torsional stacks. A comparison is made with a 2-state fit of similar data for $\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}$CH$\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}$$\mathrm{<mrow\; data-mjx-texclass="ORD">12</mrow>}$CH$\mathrm{<mrow\; data-mjx-texclass="ORD">3</mrow>}.$