R-BRANCH MICROWAVE SPECTRUM OF METHYLAMINE

Abstract

The a-type R-branch $J=1 \leftarrow 0$ and $J = 2\leftarrow 1$ multiplets of $CH_{3}NH_{2}$ have been investigated at 44 GHz and 88 GHz, respectively, in order to provide laboratory data for radio astronomy and to permit determination of certain of the a-type molecular constants. Identification of all torsion- inversion components of the $J= 2 \leftarrow 1$ multiplet has been made for the ground torsional state, and partial identification for the first and second excited torsional states, Further progress has also been made on the assignment of the $J = 1 \leftarrow 0$ $multiplet^{1}$, and on the resolution of some ambiguities in the spectrum. The fitting of the spectra to a model employing semiempirical torsion-rotation distortion parameters will be discussed, and the preliminary molecular constants presented.