Ultrahigh-resolution spectroscopy for methyl mercaptan at the ν2-band by a distributed feedback interband cascade laser

- Ultrahigh-resolution absorption spectroscopy of the ν2 band of methyl mercaptan at room temperature.
- Air-broadened line positions, intensities and for 39 transitions.
- Validation of spectroscopic data.
- Comparison to the PNNL is discussed.

The ultrahigh-resolution mid-infrared absorption spectrum of methyl mercaptan (CH3SH) was recorded and analyzed in the region of 2945-2953 cm-1, where the strong ν2-band is located. Benefitting from the high-resolution of tunable laser absorption spectrometry (TLAS) with a distributed feedback interband cascade laser (DFB-ICL), 12-strong and 27-weak air-broadened absorption peaks belonging to the ν2-band of CH3SH were assigned with resolution of better than 2.24×10-5 cm-1(~26 fm/670 kHz) and absorption cross section precision of 2.0%, at temperature of 298.15 K and pressure of 1 atm. For further description of the assigned transitions, the spectral line parameters and cross sections of these absorption peaks versus pressure were investigated. These ultrahigh resolution air-broadened spectra can be used as reference data for CH3SH remote sensing and absolute spectral measurement applications.