Collisional deactivation of the electronically excited atoms, S(31D2) and S(31S0), by the noble gases

Abstract

Rate data for the relaxation of S(3¹D₂) and S(3¹S₀) by Xe, Ar and He have been obtained using kinetic absorption spectroscopy in the vacuum ultra-violet. The results are discussed, together with data for O(2¹D₂) and O(2¹S₀), in terms of potential curves resulting from the collision between the optically metastable, electronically excited atoms and the noble gases. These considerations are successful in accounting for the relatively high quenching efficiency observed for the ¹D₂ state, the increase in efficiency with atomic weight of the noble gas and the low efficiencies for quenching of the ¹S₀ state. A new lower limit is presented for the rate of reaction between S(3¹D₂) and H₂. This result is discussed in terms of the potential surfaces available for chemical reaction; the difference in reactivity between S(3¹D₂) and S(3¹S₀) with H₂ is accounted for.