THE MICROWAVE SPECTRUM OF TRIFLUORONITROMETHANE

Abstract

Several series of $\Delta J = + 1$ transitions have been observed in the rotational spectrum of $CF_{3}NO_{2}$. The spectrum has the same qualitative features as that of $CH_{3}NO_{2}$, but is more complicated. Because the moment of inertia of the $CF_{3}$ group is large, many internal rotation states are populated. In addition, the low asymmetry of the molecule results in a close spacing of the lines over a relatively narrow frequency range so that the Stark effect of most lines is not resolvable and many of the lines themselves cannot be resolved. A number of lines have, however, been assigned and the rotational constants $A(NO_{2})$, B, and C have been determined. The barrier to internal rotation will be evaluated.