RESUMO
An attempt has been made to use modern quantum methods to codify the data base concerning bond dissociation energies in hydrocarbons. Calculations have been performed using two hybrid DFT methods, the well-known B3LYP formalism and a newly developed alternative named KMLYP. CBS-Q has also been employed where possible. The combination of experimental uncertainty and theoretical limitations is less than completely satisfactory. However, within uncertainties that translate to a factor of two at 1500 K, many transferable quantities are elucidated. A hybrid method has been developed for the correction of DFT calculations using group additivity. Given that the philosophy behind this work is the understanding that all data bases must be optimised for specific applications, so that avoidance of large errors is more important than absolute precision, the results appear to be quite useful. We are particularly encouraged by the performance of the KMLYP method, given its ease of application to molecules of practical interest.