Effect of self-interaction correction

Twenty-four different local and gradient-corrected density functional methods were used in a study of the reaction H + Hz-+ H2 + H. Barrier heights were calculated with a large basis set. The results were compared to those obtained by ab initio methods and experiment. It was found that conventional Kohn-Sham methods consistently and significantly underestimate the reaction barrier. In particular, the local spin-density approximation (LSDA) in unmodified form completely fails, predicting Hs to be a stable species. However, the inclusion of a self-interaction correction restores the correct qualitative features of the potential surface, and generally leads to reasonable results when pairing a gradient-corrected exchange functional with a correlation functional.