Visible absorption cross sections and integrated absorption intensities of molecular oxygen (O2 and O4)

Absorption spectra of gas-phase molecular oxygen and zero air at temperatures of 223 and 283 K have been measured in the laboratory using a coolable multipass-optics gas cell and Fourier transform spectroscopy in the wavelength range 455 to 830 nm (12,000-22,000 cm(-1)). Net absorption cross sections of the O-2 A-, B-, and gamma-bands at <0.002 nm spectral resolution, and pressures of 100 and 1000 hPa zero air have been determined. Binary absorption cross sections of the collision-induced O-4 bands at <0.18 nm spectral resolution and a pressure of 1000 hPa pure oxygen have been determined, with corrections for the O-2 gamma-band absorption. Calculated integrated absorption intensities and, for the O-2 A- and B-bands, "effective" Einstein A-coefficients are compared with previous literature values.