Structure of the floating water bridge and water in an electric field

摘要

The floating water bridge phenomenon is a freestanding rope-shaped connection of pure liquid water, formed under the influence of a high potential difference (approximately 15 kV). Several recent spectroscopic, optical, and neutron scattering studies have suggested that the origin of the bridge is associated with the formation of anisotropic chains of water molecules in the liquid. In this work, high energy X-ray diffraction experiments have been performed on a series of floating water bridges as a function of applied voltage, bridge length, and position within the bridge. The two-dimensional X-ray scattering data showed no direction-dependence, indicating that the bulk water molecules do not exhibit any significant preferred orientation along the electric field. The only structural changes observed were those due to heating, and these effects were found to be the same as for bulk water. These X-ray scattering measurements are supported by molecular dynamics (MD) simulations which were performed under electric fields of 10⁶ V/m and 10⁹ V/m. Directional structure factor calculations were made from these simulations parallel and perpendicular to the E-field. The 10⁶ V/m model showed no significant directional-dependence (anisotropy) in the structure factors. The 10⁹ V/m model however, contained molecules aligned by the E-field, and had significant structural anisotropy.