关键词: 径向分布函数, 介电常数, 平均场模型, 诱导电场, 偶极矩

Abstract:

A series of molecular dynamics simulations with or without external electric field have been carried out for a bulk water with periodic boundary condition. The difference in radial distribution function of interatomic O…O distance is subtle, with and without external electric field, except for the orientation of dipole moments of water molecules. Without the applied external electric field, distribution of the orientation angle of dipole moments is rather broad. The induced local electric field is analyzed as a function of altitude in direction of electric field. The variation of the local induced electric field is increased as the increase of the external electric field. The local induced electrostatic energy is mainly originated from the increase in the ordering of dipole orientation under the external electric field. Dielectric constant is evaluated according to the fluctuation of total dipole moment of the whole system. The change of relative dielectric constant under the different external electric fields can be described in an exponential decay equation as the increase of the strength of electric field. This simple rule can be applied to understand the electrostatic interaction and local induced electric field under various electrochemical environments.