Intracavity Laser Absorption Spectroscopy of 13C16O2 near 734 nm

International audienceWe report the first intensity measurements for the very weak 20052-00001 band of the 2ν1 + 5ν3 triad of 13C16O2 near 734 nm by high sensitivity Intracavity Laser Absorption Spectroscopy. A noise equivalent absorption αmin ˜ 2 × 10‑10 cm‑1 was achieved with an absorption pathlength equivalent to 50.3 km. The derived intensity values (on the order of 10‑28 cm/molecule) are found in good agreement with recent ab initio calculations. The dominant term of the effective dipole moment of the 2ν1 + 5ν3 triad was obtained from a fit of the measured line intensity values and used to generate the line list of the 2ν1 + 5ν3 triad of 13C16O2 and 12C16O2