THE MICROWAVE SPECTRUM OF trans-2,3-$EPOXYBUTANE^{\ast}$

Author Institution: Department of Chemistry, Harvard UniversityThe microwave spectrum of $trans-CH_{3}CHCHCH_{3}$ has been studied from 8--40 Gc. The rotational constants and dipole moment $(\mu = \mu_{b})$ of the main isotopic species in the ground torsional state were found to be $A = 12,237.38 Mc., B = 3,423.02, C = 3,072.52 (\kappa = -0.9235122)$ and $2.02\pm 0.04$ debyes. The Pierce theory of internal rotation in two-top molecules was extended to fourth order to obtain the barrier to internal rotation from those lines which showed splitting; the resulting barrier is $2217 \pm 200$ cal/mole. These results will be discussed in terms of steric hindrance in this molecule and the analogous cis-isomer studied by Sage. $^{\ast}$ This research was made possible by support extended Harvard University by the Office of Naval Research