The absorption coefficient of SO2 under atmospheric conditions was measured at twenty DF laser lines. Weak absorption (α* ≲ 0.003 cm-1 atm-1) was found for a few wavelengths around 3.7 µm. Only the P4(6) line at 3.9843 µm (ν = 2509.86 cm-1) is strongly absorbed [α* =(0.44 ± 0.01) cm-1 atm-1]. The pressure dependence of the P4(6) cross section was measured. Self-broadening and foreign-gas broadening coefficients are between 1.5 and 5 MHz/Torr, and the distance from the P4(6) DF line to the center of the nearest SO2 line is (0.0043 ± 0.0004) cm-1.
© 1980 Optical Society of America
J. Altmann and P. Pokrowsky, "Sulfur dioxide absorption at DF laser wavelengths," Appl. Opt. 19, 3449-3452 (1980)