Investigation of the Spectral Line Intensities of the ν9 Band of the Trans-Conformer of Ethylene

The intensities of 740 vibrational-rotational lines of the ν9 fundamental band in the IR spectrum of the trans-C2H2D2 molecule are first analyzed. The Hartmann–Tran profile is used to fit the line contour. More than 2700 spectral transitions are assigned using the ground state combination difference method and the isotopic substitution theory. The special features of the spectral line broadening and the influence of the parameters of the Hartmann–Tran line profile on the accuracy of line contour reconstruction are considered.