Temperature-dependent photoabsorption cross section measurements of O2 at the NI airglow and auroral emission lines

In this Letter, we report the first temperature-dependent measurements (at 295, 373, 473 and 573 K) of the O2 photoabsorption cross sections at the aeronomically important NI airglow and auroral emission lines (at 1200, 1492 and 1742 إ) in the far ultraviolet spectral region. A high-current low-voltage argon mini-arc source was used as the light source in the present measurements. The measurements were carried out at a spectral resolution of 0.30 إ at full-width-at-half-maximum (FWHM). Direct application of the Beer-Lambert absorption equation yielded the absolute photoabsorption cross sections for O2 at each NI emission lines of interest.