Small representative benchmarks for thermochemical calculations

We propose a small set of atomization energies and a small set of barrier heights as benchmarks for comparing and developing theoretical methods. We chose the data sets to be subsets of the Database/3 collection of atomization energies and barrier heights. We show that these data sets, consisting of six barriers and @@@ atomization energies, are very representative of all the atomization energies and barrier heights in @@@ 3, and we call them the AE6 and BH6 benchmarks, respectively. Benchmark values are tabulated for SO standard methods, including Hartree-Fock, Møller-Plesset perturbation theory, quadratic configuration interaction, coupled cluster theory, hybrid density functional theory, and multicoefficient correlation methods.