AN IMPROVED TECHNIQUE FOR THE OBSERVATION OF INFRARED CHEMILUMINESCENCE: RESOLVED INFRARED EMISSION OF OH ARISING FROM THE SYSTEM H + O 2

A multiple reflection apparatus for the observation of infrared chemiluminescence is described. By means of this apparatus infrared emission from the system H + O 2 has been identified as being due to vibrationally excited OH radicals in levels v = 1, 2, and 3 of the ground electronic state. The resolved infrared spectrum of the OH fundamental has been observed for the first time without interference from other emission. The most likely source of excited OH is the reaction H + HO 2 → OH† + OH. The vibrational 'temperature' of OH† (vibrationally excited OH in its ground electronic state) in our system is in the region of T V = 2240 °K. These findings are discussed in relation to Krassovsky's suggestion that reaction between H and O 2 could account for the Meinel hydroxyl bands in the night sky.