Knowledge Bank

“The microwave spectra of acetyl cyanide, $CH3COCN$, and the completely deuterated species, $CD3COCN$, have been studied in the region of 10,000 to 34,000 megacycles. Transitions up to $J=12$ have been assigned and the moments of inertia of the two isotopic species have been determined, allowing a partial determination of the structure to be made. Splittings due to hindered internal rotation of the methyl group have been observed for lines of the ground torsional state. These splittings are found to be in good agreement with the theory of Wilson and co-workers for a barrier to internal rotation, $V(\alpha )=V3(1-cos3\alpha )/2$ of $V3=1250$ cal/mole ($437cm-1$).”