Collisional deactivation of O(2 1D2) by the atmospheric gases

Abstract

The thermal rate constants for collisional deactivation of electronically excited oxygen atoms, O(2 ¹D₂), by N₂, O₂, N₂O, CO₂, CH₄, and H₂O have been measured at 295 K. The optically metastable atoms were produced by pulsed photolysis of O₃ at 248 nm using a KrF excimer laser and monitored by following the increase in O(2 ³P_J) concentration following quenching of O(2 ¹D₂) through the use of time‐resolved atomic resonance spectroscopy. This method of analysis obviated difficulties associated with the evaluation of the curve‐of‐growth law which were encountered in previous attempts to measure the removal of O(2 ¹D₂) using a similar technique. Rate constants reported here are in excellent agreement with those measured by observation of the weak O(2 ¹D₂) →O(2 ³P_J) emission at 630 nm. In addition, it was possible to determine the extent of physical quenching in the deactivation of O(2 ¹D₂) by H₂O, CO₂, CH₄, and N₂O.