Ab initio simulations of water and water ions

Ab initio studies of H+ and OH- in water reveal a variety of interesting structures. In the case of the OH-, an H 9O5- structure is observed in which the four hydrogen bonds with the ligands lie in a plane that also contains the oxygen atom of the anion. In the case of H+, there is strong evidence for the existence of the H9O4+ structure originally postulated by Eigen and coworkers. Proton migration in this system is relatively fast and is observed to occur via the Grotthus mechanism.