Measurements of self-broadening and self-pressure-induced shift parameters of the methane spectral lines in the 5556-6166 cm−1 range

The absorption spectra of methane at different path lengths and different pressures for three temperatures 180, 240 and 296 K have been recorded in the 5556-6166 cm−1 region using the Bruker IFS 120 HR and 125 HR high-resolution Fourier transform spectrometers. The multispectrum fitting procedure has been applied to these spectra to recover the spectral line parameters. The main goal of this procedure was the determination of self-broadening and self-pressure-induced shift coefficients and the exponents of their temperature dependences. These parameters have been derived for 406 assigned lines with good values of the signal to noise ratio. The rotational dependence of these parameters is discussed.

Research highlights► Broadening and shift parameters of CH4 in tetradecad vary greatly from line to line. ► Self-broadening parameters of CH4 in tetradecad decrease with increase of |m|. ► Average value of self-shift in tetradecad of CH4 is larger than in octad. ► Temperature exponents of self-broadening parameters depend on temperature range.