Dissipative particle dynamics: Dissipative forces from atomistic simulation

TL;DR

This paper introduces a new method to derive dissipative particle dynamics parameters directly from atomistic simulations, linking microscopic details to mesoscopic models for better accuracy.

Contribution

It presents a geometric approach to map atomistic simulations onto DPD, enabling direct extraction of interaction parameters from molecular data.

Findings

Good agreement in thermodynamic properties between atomistic and DPD models

Method provides a molecular basis for DPD parameterization

Applicable to simple supercritical fluids

Abstract

We present a novel approach of mapping dissipative particle dynamics (DPD) into classical molecular dynamics. By introducing the invariant volume element representing the swarm of atoms we show that the interactions between the emerging Brownian quasiparticles arise naturally from its geometric definition and include both conservative repulsion and dissipative drag forces. The quasiparticles, which are composed of atomistic host solvent rather than being simply immersed in it, provide a link between the atomistic and DPD levels and a practical route to extract the DPD parameters as direct statistical averages over the atomistic host system. The method thus provides the molecular foundations for the mesoscopic DPD. It is illustrated on the example of simple monatomic supercritical fluid demonstrating good agreement in thermodynamic and transport properties calculated for the atomistic system and DPD using the obtained parameters.