The Thermodynamics of the Elusive HO 3 Radical

Abstract

The Weakness of HO 3 OH radicals play a critical role in the chemistry of Earth's atmosphere. Understanding atmospheric reaction networks thus requires an accurate knowledge of OH sources and sinks. One vexing question has been whether or not a significant pool of OH binds temporarily with oxygen to form HO 3 . Le Picard et al. (p. 1258 ) have succeeded in measuring the equilibrium constant for this reaction using sensitive fluorescent tracking of OH in a laboratory apparatus. This measurement was then used to quantify the strength of the O 2 –OH bond, which was found to be too weak for the complexation to play a major role in the atmosphere.