High resolution absorption coefficients for freon‐12

Abstract

Ultra high resolution absoprtion coefficients of the Q‐branch of Freon‐12 (CCℓ₂F₂) have been obtained using tunable diode laser spectroscopy. Continuous spectra are presented from 1155 cm⁻¹ to 1163 cm⁻¹ with a spectral resolution ∼ .001 cm⁻¹. Absolute wavelength calibration was obtained using SO₂ spectra as a standard and a 5 cm Ge etalon for relative calibration between SO₂ lines. The relative accuracy of the Freon‐12 line positions was ∼ .0005 cm⁻¹. The Freon‐12 dataobtained at a pressure of .05 Torrexhibited a rich and highly structured spectra. Howeverwith the exception of three isolated features at 1158.21159and 1161 cm⁻¹ collisional broadening reduces the spectra to a structureless continuum for nitrogen pressures greater than 20 Torr. The spectra at 1161 cm⁻¹ continue to exhibit structure at atmospheric pressure.