Diode-laser spectroscopy: Pressure dependence of N2-broadening coefficients of lines in the ν4+ν5 band of C2H2

In this work, we have measured the N2-broadening coefficients of 12 absorption lines in the ν4+ν5 band of acetylene at room temperature, using a tunable diode-laser spectrometer. For each line under study, we have recorded spectra at 4-16 pressures of nitrogen ranging from 4.03 to 179.5 mbar. The line profiles were individually fitted, at each pressure, with different line shape models including fine effects as Dicke narrowing or/and speed dependence effect. From these fits, we have obtained the collisional half-widths at each pressure and then determined accurately the N2-broadening coefficients of 12 lines. After that, we have studied the pressure dependence of the collisional broadening and narrowing coefficients following the considered line profile model. Finally, our results are compared with the previous studies realized in various absorption bands.