High-temperature, high-resolution cross sections of O-2 in the 83.4 nm region

The high-resolution absorption cross-section measurements of O-2 in the 83. 0 - 83.5 nm spectral region have carried out with a resolution of 0.0008 nm and at temperatures of 295 K and 535 K, These are apparently the first suc h high-temperature cross-section measurements of O-2 in this wavelength ban d. The absorption features of the O-2 I-X (4,0) band systems are observed t o be quite diffuse with a line width of full width at half maximum (FWHM) e qual to 0.03 nm. Therefore the cross-section values of O-2 in this spectral region will not critically depend upon the resolution as long as it is bet ter than 0.03 nm, as is evident in the reported data. As the temperature in creases from 295 K to 535 K we observed an increase of 30 % in the cross-se ction values on both sides of the triplet features of the I-X (4,0) band, w hereas a 20 % decrease occurs over the peak region.