O(3P) Atom Formation by the Photolysis of Hydrogen Peroxide in Alkaline Aqueous Solutions

Article abstract of DOI:10.1021/j150651a033

The quantum yield of O(3P) atom scavengeable by cyclopentene, Φ₀(O(3P)), in the photolysis of H2O2 and HO2^- with 248-nm light was determined over the pH range 3-12.9. Φ₀(O(3P)) from H2O2, determined at pH 3, is (2.6 +/- 0.6) X 1E-4.At pH 8.7-12.9, Φ₀(O(3P))from HO2^- is essentially constant, within experimental error, at 0.08 +/- 0.015.All of the observations on the effects of pH and the concentrations of cyclopentene, H2O2, and HO2^- are consistent with the formation of O(3P) and OH^- in a primary photochemical event, with 0.08 O(3P) per photon absorbed by HO2^- escaping the cage and undergoing homogeneous reactions with cyclopentene, OH^-, HO2^-, and H2O2.The rate constants derived relative to reaction with cyclopentene are k_OH- = 0.040 +/- 0.007, k_HO2- = 0.5 +/- 0.2, and k_H2O2 = 0.15 +/- 0.03.