The nu(1), 2 nu(2), and 2 nu(3)+nu(4) band system of carbonyl fluoride

The infrared spectrum of carbonyl fluoride, COF2, has been measured in the region from 1880 to 1980 cm(-1) using a Bruker Fourier transform spectrometer at 0.003 cm(-1) resolution and diode laser spectroscopy al Doppler-limited resolution. In this region the nu(1) band at 1945 cm(-1) dominates the spectrum and is in Fermi resonance with the 2 nu(2) band at 1914 cm(-1) and in B-type Coriolis resonance with the 2 nu(3) + nu(4) band at 1936 cm(-1). From the nu(1) band, 820 lines wen successfully fitted using an S-type Watson Hamiltonian in the IIIl representation, yielding rotational and fourth order centrifugal distortion constants, a Coriolis parameter of 0.00339(24) cm(-1), and an obs-calc RMS or 0.0006 cm(-1). Only 400 lines from 2 nu(2) could be successfully fitted, with an obs-calc RMS of 0.0005 cm(-1), because of interference from nu(1) over much of the 2 nu(2) R branch. (C) 1997 Academic Press.