Comparative Study of the Reactions of ¹⁶OH and ¹⁸OH with H¹⁶O₂.

Abstract

The gas phase reactions 18 OH + H 16 O 2 → H 2 18 O + 16 O 2 (1a) 18 OH + H 16 O 2 → 16 OH + H 18 O 16 O (1b) were studied at room temperature in a discharge flow reactor with far infrared laser magnetic resonance (LMR) detection of 16 OH, 18 OH and H 16 O 16 O. The formation of 16 OH in the course of the reaction was observed. The absolute rate constant for the overall removal of 18 OH in excess of H 16 O 16 O was determined. Each run was accompanied by a control experiment replacing the initial 18 OH by the same amount of 16 OH. From these experiments a branching ratio is obtained of k 1a /( k 1a + k 1b ) = 0.52 ± 0.08