Critical assessment of density functional methods for study of proton transfer processes. (FHF)−

Most variants of density functional theory (DFT) yield a proton transfer barrier in (F…H…F)− which is considerably smaller than the best correlated conventional ab initio results, with a large polarized basis set. The agreement is best for DFT methods with nonlocal exchange and correlation functionals, especially hybrid approaches which mix Hartree-Fock and optimized r(FH).