High resolution absorption cross-section measurements of ozone at 195 K in the wavelength region 240–350 nm

Cross-sections of the Hartley-Huggins bands of 03 at the temperature 195 K have been obtained from photoabsorption measurements at column densities in the range 2 × 10¹⁷?1 × 10²¹ cm^?2 throughout the wavelength region 240–350 nm with a 6.65 m photoelectric scanning spectrometer equipped with a 2400 lines mm^?1 grating and operated at an instrumental width (FWHM) of 0.003 nm. The assumptions made in putting the measured relative cross-sections on an absolute basis are discussed. Fine structure in the cross-section observed in the Huggins bands is illustrated in the region 323–327 nm where shallow features of width 0.01–0.02 nm occur superposed on a stronger apparent continuum exhibiting broader wavy structure.