The rotational spectrum of methyl cyanide-d3: Analysis of the isotopic species and the low-lying excited states

Abstract The rotational spectrum of methyl cyanide- d 3 has been measured up to 400 GHz. The ground state spectra of the 13 C and 15 N isotopomers have been analyzed. These data have been used to notably improve the accuracy of the rotational and centrifugal distortion constants. The rotational spectra of the degenerate vibrational states v 8 = 1 and v 8 = 2 have also been analyzed. Accurate rotational, centrifugal distortion, and vibration-rotation interaction constants have been determined.