Representative Benchmark Suites for Barrier Heights of Diverse Reaction Types and Assessment of Electronic Structure Methods for Thermochemical Kinetics

We propose three small sets of barrier heights for heavy-atom transfer, nucleophilic\nsubstitution, and unimolecular and association reactions as benchmarks for comparing and\ndeveloping theoretical methods. We chose the data sets to be statistically representative subsets\nof the NHTBH38/04 database. Each data set consists of 6 barrier heights; we call these small\nbenchmark suites HATBH6, NSBH6, and UABH6. Benchmark values are tabulated for 205\ncombinations of theory level and basis set. The theory levels studied include single-level wave\nfunction theory like Hartree−Fock, Møller−Plesset perturbation theory, quadratic configuration\ninteraction, and coupled cluster theory; they also include multicoefficient correlation methods,\nlocal and hybrid density functional theory, and semiempirical molecular orbital methods. The\nthree new representative data sets are combined with a previous representative data set for\nhydrogen-transfer reactions to form a new compact but diverse and representative data set\ncalled DBH24. Comparison of a large number of methods for their performance on DBH24 leads\nus to recommend the following methods for barrier height calculations, in order of decreasing\ncost: G3SX, BMC-CCSD, PWB6K, BB1K, M06-L, MPW1K, HF/MIDI!, and PM3.