Absolute OH Quantum Yields in the Laser Photolysis of Aqueous Solutions of Nitrate, Nitrite and H₂O₂AT 308 and 351 NM

Summary

Absolute quantum yields for the formation of OH radicals in the laser photolysis of aqueous solutions of NO ^-₃ , NO ^-₂ and H₂O₂ at 308 and 351 nm and as a function of pH and temperature have been measured. A scavenging technique involving the reaction between OH and SCN- ions and the time resolved detection by visible absorption of the (SCN)? radical ion was used to determine the absolute OH yields. The following results were obtained:

$${\Phi _{OH}}\left( {N{O_3}\overline {} } \right) = 0.017\exp \left[ {1800\left( {\frac{1}{{298}} - \frac{1}{T}} \right)} \right]at308and351nm$$

$${\Phi _{OH}}\left( {N{O_2}\overline {} } \right) = 0.07\exp \left[ {1560\left( {\frac{1}{{298}} - \frac{1}{T}} \right)} \right]at308nm$$

$${\Phi _{OH}}\left( {N{O_2}\overline {} } \right) = 0.046\exp \left[ {1800\left( {\frac{1}{{298}} - \frac{1}{T}} \right)} \right]at351nm$$

$${\Phi _{OH}}\left( {{H_2}{O_2}} \right) = 0.98\exp \left[ {660\left( {\frac{1}{{298}} - \frac{1}{T}} \right)} \right]at308nm$$

$${\Phi _{OH}}\left( {{H_2}{O_2}} \right) = 0.96\exp \left[ {580\left( {\frac{1}{{298}} - \frac{1}{T}} \right)} \right]at351nm$$