Integration Schemes for Dissipative Particle Dynamics Simulations: From Softly Interacting Systems Towards Hybrid Models

TL;DR

This paper evaluates the performance of various integration schemes in dissipative particle dynamics simulations, highlighting artifacts in physical observables especially in systems dominated by random and dissipative forces.

Contribution

It provides a systematic comparison of integration schemes in hybrid models combining microscopic and meso-scale descriptions, revealing their limitations and artifacts.

Findings

Common integrators can produce artifacts in physical observables.

Artifacts are more pronounced in systems with soft, dissipative interactions.

Integration scheme quality is crucial in models with significant random and dissipative forces.

Abstract

We examine the performance of various commonly used integration schemes in dissipative particle dynamics simulations. We consider this issue using three different model systems, which characterize a variety of different conditions often studied in simulations. Specifically we clarify the performance of integration schemes in hybrid models, which combine microscopic and meso-scale descriptions of different particles using both soft and hard interactions. We find that in all three model systems many commonly used integrators may give rise to surprisingly pronounced artifacts in physical observables such as the radial distribution function, the compressibility, and the tracer diffusion coefficient. The artifacts are found to be strongest in systems, where interparticle interactions are soft and predominated by random and dissipative forces, while in systems governed by conservative interactions the artifacts are weaker. Our results suggest that the quality of any integration scheme employed is crucial in all cases where the role of random and dissipative forces is important, including hybrid models where the solvent is described in terms of soft potentials.