Direct observation of S(31S0) atoms in the vacuum ultra-violet photolysis of COS

Abstract

Direct observations on the specific quantum states formed in the primary process following vacuum ultra-violet photolysis of COS are reported. The optically metastable S(3¹S₀) atom has been observed in absorption and the kinetics of its decay in the presence of COS, H₂, Ar, and Xe have been monitored. Rate constants which represent the sum of reaction and collisional relaxation are given for COS and H₂ as 1.0 ± 0.2 × 10^–11 and 4.0 ± 1 × 10^–15 cm³ molecules^–1 sec^–1 respectively. S(3¹S₀) is relatively less reactive towards H₂ than S(3¹D₂) despite the greater exothermicity for reaction. Indirect evidence for the rapid removal of S(3¹D₂) from these systems is also discussed.