title: Ab initio molecular dynamics study of dissociation of water under an electric field.
abstract: The behavior of liquid water under an electric field is a crucial phenomenon in science and engineering. However, its detailed description at a microscopic level is difficult to achieve experimentally. Here we report on the first ab initio molecular-dynamics study on water under an electric field. We observe that the hydrogen-bond length and the molecular orientation are significantly modified at low-to-moderate field intensities. Fields beyond a threshold of about 0.35  V/Å are able to dissociate molecules and sustain an ionic current via a series of correlated proton jumps. Upon applying even more intense fields (∼1.0  V/Å), a 15%-20% fraction of molecules are instantaneously dissociated and the resulting ionic flow yields a conductance of about 7.8  Ω-1 cm-1, in good agreement with experimental values. This result paves the way to quantum-accurate microscopic studies of the effect of electric fields on aqueous solutions and, thus, to massive applications of ab initio molecular dynamics in neurobiology, electrochemistry, and hydrogen economy.
authors.affiliation: IMPMC, CNRS-UMR 7590, Université P & M Curie, 75252 Paris, France. marco.saitta@impmc.upmc.fr
authors.forename: A Marco
authors.initials: AM
authors.lastname: Saitta
authors.forename: Franz
authors.initials: F
authors.lastname: Saija
authors.forename: Paolo V
authors.initials: PV
authors.lastname: Giaquinta
mesh_terms: D004574:Electromagnetic Fields; D008956:Models, Chemical; D062105:Molecular Docking Simulation; D011789:Quantum Theory; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water