It was noted that the use of pulsed neutron sources and time-of-flight spectrometers had raised incoherent inelastic neutron scattering to the level of a major technique in vibrational spectroscopy. This had yielded new information on proton dynamics in solids, and new entities such as free protons, tetrahedral (H+)4 and H3O+ had been characterized. Quantum proton transfer along H bonds was revealed.

F.Fillaux: Physica B, 1995, 213-214, 619-24