Measurement of O2 and O3 absorption cross-sections in the 180-270 nm by controlling the conversion of O2 to O3 in the linear-absorption region

Oxygen (O2) and ozone (O3) are of crucial importance to human health and environmental sustainability. Concentrations of O2 and O3 can be measured by UV absorption spectroscopy, in which the absorption crosssection (ACS) is a very critical physical parameter for calculating concentrations. However, the existing ACS of O2 and O3 are biased because the conversion of O2 to O3 and nonlinear effects in absorption are ignored in the measurement of ACS. In this study, the ACS for O2 and O3 are obtained by considering the conversion of O2 to O3 and the nonlinear effects. First, the conversion of O2 to O3 is inhibited by controlling gas flow rate and light intensity in the measurement of O2 and O3 ACS. Then the concentration of O3 is indirectly calculated by controlling conversion of O2 to O3 during the measurement of ACS of O3. Next, the linear-absorption regions for O2 and O3 are determined by constructing the relationship between absorption intensities and concentrations to eliminate the influence of nonlinear effect. The maximum ACS for oxygen and ozone are 7.84 x 10-20 cm2/ molecule (7 = 180.51 nm) and 1.32 x 10-17 cm2/molecule (7 = 255.39 nm) by controlling conversion of O2 to O3 in the linear-absorption region, respectively.