Unsaturated Radicals ROO, RO and

The enthalpy of reaction, is an important parameter in the kinetics related to 

It is difficult to determine these thermochemical parameters from experiment, because it is hard to monitor the precursor hydrocarbon radical and the formed peroxy radical. The experiment is further complicated by the presence of reactions to new products by the energized peroxy radicals which can prevent the monitoring of equilibrium. Experiments on ion methods using proton affinity or basicity, often with mass spectrometric analysis, are also utilized to determine enthalpies of formation of radicals. Our methods rely heavily on experimentally determined thermochemical data and we would like to point out that this data is very valuable to validate the computational methods. 

An alternate method is the use of computational chemistry to estimate these values from the enthalpy of formation of the alkyl radical, and the respective peroxy radical. 

As with the stable hydroperoxide molecules above, the isodesmic reactions for the unsaturated alkoxy and peroxy radicals resulting from C—OOH, CO—OH and COO—H bond cleavage reveal that enthalpies on a number of vinyl and ethynyl, alkoxy and peroxy radicals are needed for use as reference species. Limited data are available for these radical species enthalpies [47] and this data is listed Appendix A. 

The peroxy radicals listed in Table 3.8 are calculated with DFT and use of the following isodesmic reactions  

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