H + H2 quantum dynamics using potential energy surfaces from density functional theory

Density functional theory (DFT) potential energy surfaces are determined for the collinear H + H2 reaction, using the standard B3LYP, B97-1, and B97-2 hybrid exchange-correlation energy functionals. The surfaces are used to calculate state-to-state reaction probabilities. B3LYP is wholly inadequate, whereas B97-1 and B97-2 yield a realistic description of the reaction dynamics, reproducing the widths and spacings of the resonances. Further improvements in functional quality are required, particularly with regard to the height and width of the DFT barrier.