The enthalpy of formation of trioxy radicals ROOO (R = H, CH₃, C₂H₅). An ab initio study

Abstract

Enthalpies of formation of trioxy radicals, ROOO, with R = H, CH₃, and C₂H₅, are calculated, along with values for the corresponding species R, RO, RO₂, RO₂H, and RO₃H using the G2M(RCC) approach, a modified Gaussian-2 model extrapolating the RCCSD(T)/6-311 + G(3df,2p) level of theory. Where applicable, CBS-QCI/APNO calculations were performed. The enthalpy of formation ΔH_f⁰ (298K) of cis-HOOO (²A″) was determined to be 6.1 kcal/mol using the CBS-QCI/APNO model. The HO-OO bond dissociation energy was calculated using the G2M(RCC) formalism to be +1.31 kcal/mol for 0K which is very close to the result of +1.15 kcal/mol using the CBS-QCI/APNO model. The CH₃O-OO and C₂H₅O-OO bond energies were calculated to be −0.87 (G2M(RCC)) and −0.5 kcal/mol (G2M(RCC,MP2)).

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