Microwave Spectrum of Cyclohexene

The microwave spectrum of cyclohexene has been investigated in the frequency region from 7.3 to 27 Gc/sec with a conventional Stark modulation spectrometer, and the spectrum in the ground vibrational state has been assigned. The dipole moment lies entirely along the b-principal axis; its value, as obtained from the Stark displacements, is 0.332±0.012D. From the rotational constants and the orientation of the dipole moment, it can be concluded that the equilibrium conformation is a “half-chair” form. Its most probable structure has been determined.