The temperature dependence of the rate constant for the reaction of hydroxyl radicals With nitric acid

The flash photolysis resonance fluorescence technique has been used to measure the rate constant for the reaction products over the temperature range 225–443 K. The data below room temperature can be fit to the expression k1 = (1.05±0.40) × 1014 exp [(759±100)/T] cm3 molec−1 S−1. This equation, however, markedly underestimates the values of k1 above 300 K. An interpretation of the behavior is presented, and implications of these values for k1 on stratospheric reaction cycles are discussed.