Nuclear quantum effect and H/D isotope effect on F + (HO) → FH + (HO)OH (n = 1-3) reactions.

Potential energy profiles for F + (HO) → FH + (HO)OH (n = 1-3) reactions, which are widely relevant to solvent effects on chemical reactions, have been investigated using the conventional quantum mechanical (QM) methods and our multicomponent QM (MC_QM) methods, which can take account of nuclear quantum effect of light nucleus, such as proton and deuteron. For these reactions, Li and co-workers [G. Li et al., J. Phys. Chem. A 117, 11979 (2013)] reported that (i) for F + HO → FH + OH reaction, MPW1K density functional gave the best barrier among 49 kinds of density functionals and (ii) the energy of transition state of F + (HO) → FH + (HO)OH reaction is lower than that of the separated reactant molecules by the contribution of the second water molecule using high-accuracy CCSD(T)/cc-pVQZ calculations. We have found that ω B97XD density functional reasonably reproduces the CCSD(T) geometries well, whereas MPW1K was not suited for analyzing F + (HO) → FH + (HO)OH reaction. Our MC_QM calculations reveal that nuclear quantum nature of hydrogen nucleus lowers the activation barrier of the reactions. The H/D isotope effect on F + (HO) → FH + (HO)OH (n = 1-3) reactions was also investigated.