E. Essebbar, A. Farooq
Journal of Quantitative Spectroscopy and Radiative Transfer, 149, pp. 241-252, (2014)
Methane, Line intensities, Collisional broadening, Collisional narrowing, Difference-frequency-generation laser
The P-branch of methane׳s ν3 band is probed to carry out an extensive study of the 2905–2908 cm−1 infrared spectral region. Absolute line intensities as well as N2-, O2-, H2-, He-, Ar- and CO2-broadening
coefficients are determined for nine transitions at room temperature.
Narrowing parameters due to the Dicke effect have also been
investigated. A narrow emission line-width (~0.0001 cm−1) difference-frequency-generation (DFG) laser system is used as the tunable light source. To retrieve the CH4
spectroscopic parameters, Voigt and Galatry profiles were used to
simulate the measured line shape of the individual transitions.