MICROWAVE SPECTRUM OF N---METHYL---ETHYLIDENEIMINE

Author Institution: Laboratory for Physical Chemistry, Swiss Federal Institute of TechnologyN-Methyl-Ethylideneinine is the simplest example of a molecule with two inequivalent methyl groups. The microwave spectrum of the trans isomer was recorded between S and 40 GHz. It showed the effects of the internal rotations of both methyl tops. Each rotational transition was split into five components according to the different irreducible representations of the symmetry group. The intensity ratios were consistent with the spin-statistical weights of the methyl protons. In addition to the internal rotors splittings, the spectrum was further complicated by the nuclear quadrupole multiplets of the nitrogen. The IAM for two inequivalent tops was used in the high barrier approximation for the analysis of the appropriate splittings. The rotational constants, quadrupole coupling constants, and the torsional barriers for both methyl groups could be determined