EXPERIMENTAL-DETERMINATION OF SO2, C2H2, AND O-2 UV ABSORPTION CROSS-SECTIONS AT ELEVATED-TEMPERATURES AND PRESSURES

A heated and pressurized quartz cell with 150.5-mm pathlength was used to experimentally determine UV absorption spectra and further absorpt ion cross sections of SO2, C2H2 and O-2 in the wavelength range betwee n 200 and 400 nm. Spectra were recorded at room temperature, and at 60 0 and 800 degrees C and at absolute pressures between 1 and 6 bar. A 3 0-W deuterium lamp was used as a light source, and the light was detec ted with a photomultiplier tube through a 0.4-m Czerny-Turner monochro mator. Slit widths of the monochromator were adjusted to achieve a 5 A ngstrom measurement bandwidth, and the scan through the wavelength ran ge was made in 5 Angstrom steps, For each individual temperature and p ressure level, a reference spectrum was first recorded with the cell f illed with nitrogen, After this, the cell was filled with the selected species mixed with nitrogen, and the absorption spectra were recorded in similar conditions, The studied gas mixtures were calibrated to 3% accuracy.