Line-by-line spectroscopic parameters of HFC-32 ro-vibrational transitions within the atmospheric window around 8.2 micron

Difluoromethane (CH2F2,HFC-32) presents strong ro-vibrational bands within the 8-12 μm atmospheric window and hence it represents a greenhouse gas able of contributing to global warming. Numerous spectroscopic studies have been devoted to this molecule, however, much information on line-by-line parameters, like line intensities and broadening parameters, is still lacking. In this work, line-by-line spectroscopic parameters are retrieved for several CH2F2ro-vibrational transitions belonging to the ν7band located around 8.5 μm. Self-broadening as well N2- and O2- broadening experiments are carried out at room temperature by using a tunable diode laser (TDL) spectrometer. The line shape analysis of CH2F2self-broadened spectra leads to the determination of resonant frequencies, integrated absorption coefficients and self-broadening parameters, while CH2F2-N2and CH2F2-O2broadening coefficients are obtained from foreign-broadening measurements. In addition, the broadening parameters of CH2F2in air are derived from the N2- and O2- broadening coefficients. The results of the present work provide fundamental information to measure the concentration profiles of this molecule in the atmosphere through remote sensing spectroscopic techniques.