Recently, Bove et al. (Phys. Rev. Lett. 103 165901) have found a supporting evidence for the existence of concerted proton tunneling along hydrogen bonds of six-membered rings in ice Ih using neutron incoherent quasi-elastic scattering measurement. Since the height of the potential barrier can be controlled by the distance between the nearest oxygen atoms or by the external pressure, study of pressure effect on tunneling is interesting and important to understand hydrogen bonds under high pressure. In this study, the pressure effect, its physical consequences, and experimental measurement are discussed.
In ice phases with random hydrogen bonds, water molecules are dancing the dance of concerted quantum tunneling, hand in hand, in a circle of six members. We study theoretically how the rhythm of the dance changes with pressure and suggest how to observe the dance experimentally.