Effect of solvent fluctuations on proton transfer dynamics: a hybrid AM1/MM molecular dynamics simulation on the [H3N–H–NH3]+ system Original Research Article

Combined AM1/TIP3P Molecular Dynamics simulations have been carried out to investigate proton transfer dynamics in aqueous solution for the proton-bound ammonia dimer model system. The distance between nitrogen atoms has been fixed to 2.62 Å so that proton transfer events occur every 10–20 ps in average. The chemical reaction is clearly shown to be preceded by a solvent fluctuation which starts about 700 fs before reaching the transition structure.