Absolute intensities in the ν1, 2ν2, 2ν3 + ν4 band system of carbonyl fluoride

Abstract

The IR spectrum of carbonyl fluoride, COF ₂ , has been measured in the region 1880–1980 cm ⁻¹ using a Bomem Fourier transform spectrometer under 0.005 cm ⁻¹ resolution at a gas pressure of 3.2 Torr, 10 cm pathlength and at room- and stratospheric (ca. 200 K) temperatures. In this region the ν ₁ band at 1945 cm ⁻¹ dominates the spectrum and is in Fermi resonance with the weaker 2ν ₂ band at 1914 cm ⁻¹ , and in B-type Coriolis resonance with the 2ν ₃ + ν ₄ band at 1936 cm ⁻¹ . The absorption coefficients of this band system have been determined from the experimental spectra and the integrated intensity in this region is found to be 3.07 × 10 ⁻¹⁷ cm molecule ⁻¹ at room temperature and 3.26 × 10 ⁻¹⁷ cm molecule ⁻¹ at ca. 200 K. Using calculated spectra the integrated intensities were predicted to be 2.90 × 10 ⁻¹⁷ cm molecule ⁻¹ and 3.01 × 10 ⁻¹⁷ cm molecule ⁻¹ , respectively using transition dipole moments of 0.1592 D for ν ₁ and 0.1097 D for 2ν ₂ .† The small discrepancy in integrated intensity can be accounted for from thermally populated states, whose contribution was not calculated.