15min:

JOHN M. HERBERT, Department of Chemistry, University of California, Berkeley, CA 94720; ANNE B. MCCOY, Department of Chemistry, The Ohio State University, Columbus, OH 43210; AND JOHN F. STANTON, Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712.

We investigate a nonadiabatic two-state mechanism for reaction of alkylperoxyl radicals (ROO) with nitric oxide, an important step in the tropospheric ozone cycle. In our proposal, which is supported by high-level ab initio\/ electronic structure calculations for R = CH₃, the pernitrite adduct ROONO propagates initially on a diabatic potential surface that correlates asymptotically with the A~²\!B₂ state of NO₂. This potential intersects a second diabatic potential corresponding to the stable nitrate species RNO₂, which correlates with ground-state (X~²\!A₁) NO₂. Near the intersection of these two surfaces, ROONO exhibits substantial diradical character. Diabatic potentials for the model system FONO have been developed based on CCSD(T)/cc-pVTZ electronic structure calculations. Here we report the results of classical and quantum dynamics simulations for FO + NO FONO FNO₂.