THE SUBMILLIMETER-WAVE SPECTRUM OF PROPIONITRILE (C2H5CN)

The laboratory millimeter-wave and submillimeter-wave rotational spect rum of propionitrile (ethyl cyanide, C2H5CN) in its ground vibrational state has been extended through J = 70 and K(a) = 36. Transitions mea sured in this study are in the frequency range 250-610 GHz. A fit of 9 52 transitions including 732 new measurements to a Watson A-reduced Ha miltonian has yielded a complete set of quartic and sextic distortion constants, in addition to six octic distortion constants. Internal rot ation and hyperfine splittings have not been resolved, so they are not included in the analysis. Predicted transition frequencies for a larg e number of additional transitions of interest to radioastronomers are provided.