Mozurkewich, M.Benson, S.W.2010-06-222010-06-221985Int. J. Chem. Kin., 17, 787-807.http://hdl.handle.net/10315/4266The negative temperature dependence, pressure dependence, and isotope effects of the self-reaction of HO2 are modeled, using RRKM theory, by assuming that the reaction proceeds via a cyclic, hydrogen-bonded intermediate. The negative temperature dependence is due to a tight transition state, with a negative threshold energy relative to reactants, for decomposition of the intermediate to products. A symmetric structure for this transition state reproduces the observed isotope effect. The weak pressure dependence for DO2 self-reaction is due to the approach to the high-pressure limit. Addition of a polar collision partner, such as ammonia or water vapor, enhances the rate by forming an adduct that reacts to produce deexcited intermediate. A detailed model is presented to fit the data for these effects. Large ammonia concentrations should make it possible to reach the high-pressure limit of the self-reaction of HO2.enThe definitive version is available at www3.interscience.wiley.comArticlehttp://www3.interscience.wiley.com/journal/5000443/home?CRETRY=1&SRETRY=0http://www3.interscience.wiley.com/cgi-bin/fulltext/109607466/PDFSTART