SPACE-TIME CORRELATED REACTION FIELD - A STOCHASTIC DYNAMICAL-APPROACH TO THE DIELECTRIC CONTINUUM

In molecular dynamics (MD) simulations, the continuum description of e lectrostatic interactions has been based in most cases on the static r esponse of the dielectric continuum. In this work, a time-dependent re action field expression including stochastic and friction terms is der ived in analogy to the generalized Langevin equation involving hydrody namic interactions. Simulations of water using the extended simple-poi nt charge model have been performed under different boundary condition s. The effects of a time-dependent treatment of the reaction field are demonstrated by comparing the results to those of MD simulations usin g a static, instantaneous reaction field and of MD simulations employi ng the Ewald sum. It is shown for the first time that the straight cut off approach not only leads to a disruption of the time, but also of t he spatial correlation of the dipole moment. (C) 1997 American Institu te of Physics.