Kinetics of ozone photochemistry

Summary The photolysis of ozone in the u.v. Hartley Band produces metastable oxygen atoms and molecules. At wavelengths shorter than 3100 Å the primary quantum yield is probably unity but greater uncertainty exists about its value at longer wavelengths. At 2500 Å, O₂(¹_g) is produced with near unit efficiency and there is some evidence that singlet O₂ is also a primary prduct at the short wavelenght end of the Huggins band. O₂(¹ _g ⁺ ) is not a primary photolytic product at 2500 Å but is produced as a secondary product from the rapid reaction of O(¹D) with ground state O₂. O(¹D) reacts rapidly with O₃ although the nature of the products of this reaction has not been unequivocally established and there is now strong evidence against the occurrence of energy chains in dry ozone. The reaction of O(³P) atoms with O₃ has been found to have an activation energy of 4.4 kcal mole^–1.