A qualitative analysis method for multi-component gas mixtures via terahertz rotational spectroscopy.

Terahertz rotational spectroscopy is one of the most effective methods of gas sensing. However, the rich and dense spectral peaks of multi-component gas mixtures in the terahertz band increase the difficulty of gas identification. A novel qualitative analysis method is proposed based on the collision broadening mechanism coupled with terahertz spectroscopy technology. First of all, a broadening coefficients database of acetonitrile, formic acid, and formaldehyde colliding with nitrogen was established by experimental measurements and a spectral peak fitting technique. Then the broadening coefficients of the isolated peaks in binary and ternary mixtures perturbed by nitrogen were derived. Finally, the components were identified by matching the broadening coefficients of these isolated peaks with the established database. The proposed qualitative analysis method based on the collision broadening mechanism would be a new approach for identifying multi-component gas mixtures in analytical chemistry.