Knowledge Bank

The microwave spectrum of the form of fluoroacetyl fluoride in which the heavy atoms are in a plane and the fluorine atoms are mutually trans has been assigned. The rotational constants in the ground vibrational state are: $A=10,508.92Mc.,B=3,855.06Mc.,C=2,870.72Mc$. In addition, spectra due to molecules in the first and second excited states of the C-C torsion and in the first excited state of the skeletal bending vibration have been assigned. None of the observed lines of these spectra are split, and the low J lines fit very well to rigid rotor patterns. The energies of the excited torsional states and the dipole moment of the trans form of the molecule will be discussed. Evidence for the existence of a second rotational isomer will be given. $\mathrm{<mrow\; data-mjx-texclass="ORD">\ast </mrow>}$ This research was made possible by support extended Harvard University by the Office of Naval Research.