Microwave spectra of phosphoryl trifluoride in vibrationally excited states

The ground-state rotational spectra of ¹⁶OPF₃ and ¹⁸OPF₃ have been recorded and analysed to yield a structure and accurate centrifugal distortion constants.

The pure rotational spectrum of ¹⁶OPF₃ has been recorded and analysed for five of the molecule's vibrationally excited states. The analysis of the ν₅ = 1 and ν₆ = 1 states is discussed in detail and values of ζ₅₅ ^z and ζ₆₆ ^z have been obtained. In addition, information is obtained about the elusive A rotational constant for ν₆ = 1 due to an accidental near degeneracy which yields the value A _ν=4797·86 MHz.

Some of the information obtained is used to derive the harmonic force field for the OPF₃ molecule. The use of ground-state distortion constants instead of their equilibrium values is discussed.