ABSOLUTE DETERMINATION OF THE CROSS-SECTIONS OF OZONE IN THE WAVELENGTH REGION 339-355 NM AT TEMPERATURES 220-293-K

Absolute measurements of the ozone absorption coefficient in the Huggins bands at different temperatures have been carried out. Ozone is produced by an electrical discharge and stored cryogenically; differential absorption measurements are subsequently obtained in a slowly evolving mixture of ozone and molecular oxygen. High resolution (to 0.012 nm) measurements cover a spectral range (339–355 nm) where the ozone absorption shows a strong dependance on temperature. Results at 293 and 220 K are reported; they are particularly interesting in view of the utilization of this spectral region as a low-absorption reference channel for the observation of atmospheric ozone profiles by active probing techniques. Coherent radiation at two wavelengths, around 355 and 353 nm, respectively, can be obtained as third harmonic of the fundamental output of a Nd:YAG laser and by H2 Raman shifting of a XeCl excimer laser output.