Temperature-dependence of ultraviolet absorption cross-sections of alternative chlorofluoroethanes

The absorption cross-sections of HCFC-123 (CF3-CHCl2), HCFC-141b (CH3-CFCl(2) and HCFC-142b (CH3-CF2Cl) are measured between 170 and 250 nm for temperatures ranging from 295 to 210 K with uncertainties between 2 and 4 percent. They are compared with other available determinations. Temperature effects are discussed, and parametrical formulas are proposed to compute the absorption cross-section for wavelengths and temperatures useful in atmospheric modeling calculations. Photodissociation coefficients are presented, and their temperature-dependence is discussed.