The purpose of this study is to give reliable and accurate thermochemical data for HO2, HO2+, and HO2-. Their heats of formation were determined using quantum chemical calculations with the aid of high-accuracy coupled-cluster methods taking account of zero-point vibrational energies, scalar-relativistic effects, and the deficiencies of the Born-Oppenheimer approximation. Furthermore, a thermochemical network, containing 14 experimental and 7 theoretical reaction enthalpies, was set up to determine even more accurate heats of formation. The iteratively reweighted least-squares solution of the network yielded the best heat of formation estimates, which are δfH0°(HO2) = 14.85 ± 0.22, δfH298°(HO2) = 11.92 ± 0.22, δfH0°(HO2+) = 1110.56 ± 0.40, δfH298°(HO2+) = 1107.64 ± 0.40, δfH0°(HO2-) = -89.04 ± 0. 39, and δfH298°(HO2-) = -91.75 ± 0.39 kJ/mol. In addition, in line with previous accurate data δfH0°(OH) = 37.25 ± 0.03, δfH0°(OH+) = 1293.20 ± 0.03, and δfH0°(H2O2) = 129.48 ± 0.06 kJ/mol were also delivered by our network.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry