%0 Journal Article %@ 0031-9007 %A Ranea, VA %A Michaelides, A %A Ramirez, R %A de Andres, PL %A Verges, JA %A King, DA %D 2004 %F discovery:91473 %I AMERICAN PHYSICAL SOC %J PHYS REV LETT %K SURFACES, RU(0001) %N 13 %T Water dimer diffusion on Pd{111} assisted by an H-bond donor-acceptor tunneling exchange %U https://discovery.ucl.ac.uk/id/eprint/91473/ %V 92 %X Based on the results of density functional theory calculations, a novel mechanism for the diffusion of water dimers on metal surfaces is proposed, which relies on the ability of H bonds to rearrange through quantum tunneling. The mechanism involves quasifree rotation of the dimer and exchange of H-bond donor and acceptor molecules. At appropriate temperatures, water dimers diffuse more rapidly than water monomers, thus providing a physical explanation for the experimentally measured high diffusivity of water dimers on Pd{111} [Mitsui et al., Science 297, 1850 (2002)]. %Z © 2004 The American Physical Society