High-Accuracy ExtrapolatedAb Initio Thermochemistryof the Vinyl, Allyl, and Vinoxy Radicals.

Enthalpies of formation at both 0 and 298 K were calculatedaccordingto the HEAT (High-accuracy Extrapolated Ab initio Thermochemistry)protocol for the title molecules, all of which play important rolesin combustion chemistry. At the HEAT345-(Q) level of theory, recommendedenthalpies of formation at 0 K are 301.5 ± 1.3, 180.3 ±1.8, and 23.4 ± 1.5 kJ mol–1for vinyl, allyl,and vinoxy, respectively. At 298 K, the corresponding values are 297.3,168.6, and 16.1 kJ mol–1, with the same uncertainties.The calculated values for the three radicals are in excellent agreementwith the corresponding experimental values, but the uncertaintiesassociated with the HEAT values for vinoxy are considerably smallerthan those based on experimental studies. [ABSTRACT FROM AUTHOR]