Cooperative Phenomena Associated with Electron and Proton Transfer in Quinhydrone Charge-Transfer Crystal

Studies of the IR vibrational spectroscopy of single crystals of the H-bonded quinhydrone chargetransfer complexes show that a new phase transition occurs upon application of hydrostatic pressure, associated with the proton transfer in the 2D proton lattice. The temperature- and pressure-induced changes in the O-H vibrational spectra are accounted for in terms of the melting of the proton lattice due to the proton tunneling effect.