Bruenig et al Nat Comm_fig1a

Schematic trajectory of an excess proton

Schematic trajectory of an excess proton that transfers between two water molecules, together with a schematic free energy profile F(d) that exhibits a barrier and is representative of a relatively large oxygen-oxygen separation ROO. Three time scales characterize the proton trajectory, the normal-mode vibrational period of the solvated transient H3O+, τNM, the transfer-path time, τTP and the transfer-waiting time, τTW, where τTW > τTP > τNM.