Ultraviolet Absorption Spectrum of Carbonyl Sulfide

The absorption coefficients of gaseous carbonyl sulfide have been measured in the spectral region 2000 to 2650 Å. Band structure has been observed superimposed on apparently continuous absorption. The bands can be arranged into four progressions, one of which arises from population of an excited vibrational level of the ground electronic state. It is concluded from the temperature dependence of the long wavelength portion of the spectrum that the “continuous” absorption is due to a transition to a bent upper state of OCS, namely (1Δ)1A′ or (1Σ−)1A″.