CF4 combination band absorption spectroscopy

Absorption and linewidth measurements of the R+ (29) (ν2 + ν4) A14 + E9 + F114 transition in CF4 are reported as a function of gas pressure and temperature. From these a value for the Einstein A coefficient (0.0185 ± 0.0010 sec−1) is deduced. A model for low temperature absorption and a detailed analysis of additional absorption lines are given. The Doppler width reported by Eckhardt et al. (J. Mol. Spectrosc.90, 321–326 (1981)) at 150 K is confirmed, while the homogeneous linewidth is found to be 10% smaller. The frequency displacement of the absorption feature from the CO2 9R(12) emission line center is found to be (34 ± 2) MHz independent of temperature and pressure as may be expected. The room temperature absorption measurements of Radziemski et al. (Opt. Lett.3, 241–243 (1978)) at three different pressures are confirmed but the absorption is not due to a single line and therefore the corresponding dipole moment calculated from those data (Proc. Soc. Photo-Opt. Instrum. Eng.288, 209–216 (1981)) is too large.