C2H2 Overtones Near 12300 cm1 Revisited with a Very Sensitive Cavity Ring-down Spectrometer

• Published in: Chinese journal of chemical physics Vol. 22; no. 6; pp. 663 - 667
• Main Authors: Gao, Bo, Liu, An-wen, Wu, Rui-xue, Ning, Wei, Hu, Shui-ming
• Format: Journal Article
• Language: English
• Published: 01.12.2009
• Subjects: Cavity ring-down; Overtone spectrum; Near-IR; C2H2
• ISSN: 1674-0068; 2327-2244
• DOI: 10.1088/1674-0068/22/06/663-667

A cavity ring-down spectrometer (CRDS) is constructed with a single-mode continuous-wave Ti: Sapphire laser. It allows attaining a minimum detectable absorption of 1.8 1010 cm1. The spectrometer is applied to record the overtone spectrum of 12C2H2 in the 1224012350 cm1. Compared with the previous CRDS and intra-cavity laser absorption spectroscopy studies in the same region, the present measurement achieved better sensitivity and better precision as well. As a result, the ro-vibrational parameters of the high overtone bands of acetylene at 12290.12, 12311.82, and 12350.61 cm1 have been refined. The advantages of the present CRD spectrometer is also demonstrated by the newly observed and well characterized perturbation on the f component of the very weak band near 12289 cm1. The quantitative measurement capability of the spectrometer is verified with the measurement of the water lines and employed to give the absolute band intensities of those three acetylene bands.