The reaction potential in anisotropic dense fluids

Abstract

In Monte Carlo or molecular dynamics calculations for anisotropic dipolar fluids the long-range electrostatic interaction potential poses a serious problem because of the microscopic dimensions of the simulation cells. As in homogeneous bulk fluids these small system sizes necessitate a separation of the entire electrostatic potential into short- and long-range parts. Interactions due to the former are evaluated explicitly while the net effect of the latter can be taken into account via the reaction potential approach. Since short-range interactions are evaluated explicitly the range of these interactions is commonly associated with a cavity characterized by a dielectric constant ϵ = 1 which is embedded in a homogeneous dielectric of ϵ = ϵL. The total electrostatic potential Φ(r) caused by an assembly of molecular dipoles inside the cavity can be split formally into a ‘direct’ part Φ0(r) and a much smaller ‘reaction’ part R(r) due to the polarization of the surrounding dielectric by the molecular dipoles....