Ab initio quantum chemical studies of the reactions of CF3CFHO2 with HO2

The potential energy surface (PES) for the CF3CFHO2+HO2 reaction has been theoretically investigated using the DFT [B3LYP/6-311G(d,p)] and B3LYP/6-311++G(3df,3pd)//B3LYP/6-311G(d,p) levels of theory. Both singlet and triplet PESs are investigated. The reaction mechanism on the triplet surface is simple. It is revealed that the formation of CF3CFHOOH+O-3(2) is the dominant channel on the triplet surface. On the basis of the ab initio data, the total rate constants for the reaction CF3CFHO2+HO2 in the T = 210-500 K range have been computed using conventional transition state theory with Wigner's tunneling correction and have been fitted by a rate constant expression as k = 1.04 X 10(-12)(cm(3) molecule(-1) s(-1)) exp (700.33/T). Calculated transition state rate constants with Wigner's tunneling correction for the reaction CF3CFHO2+HO2 are in good agreement with the available experimental values. (C) 2006 Wiley Periodicals, Inc.