A set of standard enthalpies of formation for benchmarking, calibration, and parametrization of electronic structure methods

A comprehensive set of 600 experimental standard enthalpies of formation (ΔHf0) is presented. With its diverse species, many possessing less usual geometries and bonding situations, this compilation is capable of uncovering deficiencies in approaches of quantum chemistry that are not detectable with smaller sets of ΔHf0 values. Its usefulness in benchmarking, calibration, and parametrization of new electronic structure methods is illustrated with the development of the B3LYP/6-311++G** bond density functional scheme. This scheme, which is sufficiently inexpensive in terms of computer time and memory to allow predictions even for molecules as large as the C60 fullerene, requires only single point calculations at optimized geometries. It yields values of ΔHf0 with the average absolute error of 3.3 kcal/mol, rivaling more expensive methods in accuracy (especially for larger systems). A list of species that are poorly handled by a typical hybrid density functional used in conjunction with a moderate-size basis set is given. This list is intended for rigorous testing of new density functionals.