The microwave spectrum,structure, and dipole moment of propiolyl fluoride

The microwave spectrum of propiolyl fluoride has been observed in the frequency region 12.5–40 GHz. Rotational transitions have been assigned for the ground and two excited vibrational states of the normal isotopic species and for the ground vibrational state of the deuterated species. In each case, values for the rotational constants and centrifugal distortion constants have been obtained. The molecule has been shown to be planar and structural calculations suggest no anomalies in any of the internuclear parameters. Stark effect measurements have yielded a value of 2.98 ± 0.02 Debyes for the dipole moment.