A refined ring polymer contraction scheme for systems with electrostatic interactions

We have recently shown how path integral simulations can be streamlined by decomposing the potential into a sum of rapidly-varying short-range and slowly-varying long-range contributions. Here, we introduce an efficient way to perform this decomposition for systems with electrostatic interactions and illustrate the method with an application to a flexible water model. In the limit of large system size, where the calculation of long-range forces dominates, the present method enables path integral simulations of liquid water to be performed with less than twice the computational effort of classical molecular dynamics simulations. (C) 2008 Elsevier B. V. All rights reserved.