Theoretical Evidence for Reassignment of Two Fundamental Vibrational Modes of Tetrafluorooxirane-\u3csup\u3e16\u3c/sup\u3eO and -\u3csup\u3e18\u3c/sup\u3eO

Ab initio and density functional theory calculations confirm Craig\u27s assignment of the fundamental vibrational modes of tetrafluorooxirane with the exception that assignments of the C-F stretching modes v9 (b1) and v13 (b2) should be exchanged. The calculated structural parameters are in good agreement with results of microwave studies except for the C-C bond length for which all the calculated results are slightly too long