VIBRATION AND ROTATION SPECTRA OF ETHYL ISOCYANIDE

The molecular structure of ethyl isocyanide has been investigated through studies of the vibration and pure rotation spectra. Most of the absorption peaks in the vibrational spectrum of the gaseous and liquid states between 4000 and 200 cm-1 have been assigned to group vibrations, and, from an absorption at 203 cm-1 which is tentatively assigned to the CH3 torsion, the potential barrier to internal rotation of the methyl group is calculated to be 2800 ± 100 cal mole. The pure rotation spectrum has been assigned to a molecule having the following rotational constants: A = 27,739.8 Mc s, B = 5117.4 Mc s, C = 4662.0 Mc s. Values for the centrifugal distortion constants are also included. © 1969.