The degree of proton transfer for XH⋯NH3 (X = F, Br, HS, and HCOO) heterodimers upon attachment of an excess electron

Abstract

A DFT method is employed to elucidate the degree of proton transfer (PT) for XH⋯NH3 (X=F, Br, HS, and HCOO) heterodimers upon an excess electron attachment. Only the anionic complex of (BrH⋯NH3)− has an intermolecular barrier-free proton transfer (BFPT) with a larger vertical detachment energy (VDE) of 16.60kcal/mol. The anionic complexes without BFPT have only one (F–H⋯NH3- and HCOO–H⋯NH3-) or two minima (HS–H⋯NH3- and HS–NH4+) in the potential energy surfaces (PESs). In the latter case, there is a transition state with an energy barrier of 1.76kcal/mol. When solvent is considered as the environmental conditions, intermolecular PT occurs for anionic complexes of (H2O)n(FH⋯NH3)− and (H2O)n(HCOOH⋯NH3)−. The minimum number of water molecules is three for the former and two for the latter respectively.