The research context is SI (système international)-referenced high resolution molecular spectroscopy using mid-infrared optical frequency synthesis. This research domain is developped to improve molecular spectroscopy with outcomes in atmosphere physics, astrophysics and fundamental constant determination.

The data correspond to 1440 recordings of the nu6 (J’ = 21, Ka’ = 2, Kc’ = 20) ← (J” =21, Ka” = 3, Kc” = 19) vibrational transition at 9.17 µm in HCOOH taken under various experimental conditions given in the 5 first rows. The first column, from line 6 to the last one gives the laser frequency in Hz with respect to the center of the line. Columns 2 to 1441 lines 6 to the last one give the saturated absorption signal in arbitrary unit. The signal is obtained using third harmonic phase-sensitive detection. The detailled structure of the data file is explained in the readme file.

The data can be used to plot 1440 saturated absorption lines. They can be fitted using saturated absorption line profiles to determine the line center and the linewidth.

python, 3.6