High sensitivity cavity ring down spectroscopy of CO2 overtone bands near 790 nm

The dyad bands of C12O216 near 790 nm have been recorded with a continuous-wave cavity ring-down spectrometer. Two cold bands and the two associated hot bands are observed in this region. High sensitivity of the 1×10−10/cm level allows one to detect weak transitions with satisfied accuracy. The absolute line intensities have also been retrieved with an estimated accuracy of 2% for majority of the unblended lines. The vibrational transition dipole moment squared values and the empirical Herman-Wallis coefficients are presented for two cold bands. The comparison of the retrieved line positions and intensities with those given in the Carbon Dioxide Spectroscopic Databank shows clear deviation and indicates the empirical calculation can be further improved using the present spectroscopy data.

Research Highlights► Four overtone bands of CO2 near 790 nm were studied by CW-CRDS. ► High accuracy line parameters were obtained for the dyad bands of CO2. ► CO2 data near 790 nm in HITRAN database need to be improved.