Quantum yields for the production of Se(1S) from OCSe (1100–2000 Å)

The quantum yield of Se(4 1S0) production from OCSe has been measured over the wavelength interval 1100–2000 Å. A large yield (≳0.75) is observed between 1640 and 1800 Å, which supports the assignment 1Σ+←1Σ+ to the strong absorption observed in this region. The major emission observed is the B (3Σ−u) →X (3Σ−g) band system of Se2, the upper state being produced by the reaction of Se(1S) with OCSe. This reaction has a rate coefficient of (1.6±0.2) ×10−10 cm3 molecule−1⋅sec−1 but ? (17±3) % of the reaction produces Se2B (3Σ−u). From the short wavelength threshold of the molecular emission, a value of (2.69±0.05) eV was obtained for the dissociation energy of the OC–Se bond.