Accuracy of density functional theory methods for weakly bonded systems: The case of dihydrogen binding on metal centers

Abstract

Accurately calculating nonclassical metal-H(2) (dihydrogen) binding is crucial to the modeling of hydrogen sorbents as an important part of the hydrogen-based vehicle programs. We have performed highly accurate calculations using the Moller-Plesset second-order perturbation theory and coupled cluster theory with single, double, and perturbative triple excitations for the dihydrogen binding on four representative systems that cover a wide range of sorbent materials previously proposed for high-capacity room-temperature storage. Comparison with nine widely used density functional theory exchange-correlation functionals reveals that the Perdew-Burke-Ernzerhof and PW91 results are accurate to within a few hundredths of an eV/H(2). This validates the predictions using these methods.