| The reaction of peroxy radicals with hydroperoxy radicals represents an important chemical sink for reactive intermediates generated during the formation of air pollution. Recent experimental work has shown that the reaction of acetyl peroxy radicals is more complex than previously thought, and proceeds via three reaction pathways: CH3CO O2+HO2CH3C OOOH+O2 R20a CH3CO O2+HO2CH3C OOH+O3 R20b CH3COO 2+HO2CH3C OO+OH+O2 R20c with branching ratios of 0.4, 0.2, and 0.4 for R20a, R20b, and R20c, respectively. In this work, a plausible reaction mechanism to explain these reaction yields is proposed. To develop this reaction mechanism, master equation calculations and kinetic simulations were performed using results from quantum calculations on reactant intermediates and transition states. The calculations show that the mechanism is consistent with experimental yields, and suggest that reaction R20c may occur for a number of peroxy radicals generated during smog formation. |
