It is the object of vibrational spectroscopists to determine the poten
tial surfaces controlling atomic motion. In the case of H-bonds these
surfaces control the process of hydrogen transfer and inelastic neutro
n scattering is an ideal tool in this work. Recent neutron vibrational
spectra of several H-bonded systems have shown that the proton vibrat
ions are independent of the heavy atom motions. From studies of model
polypeptide systems proton transfer is shown to be dominated by quantu
m tunnelling effects.