Coarse-graining strategy for molecular pair interactions: A reaction coordinate study for two- and three-dimensional systems

TL;DR

This paper develops optimal reaction coordinates for molecular pair interactions in 2D and 3D, enabling minimal, symmetry-aware tables for efficient simulation of complex molecular systems.

Contribution

It introduces a non-redundant, symmetry-involving set of reaction coordinates and a methodology for deriving effective pair potentials using Boltzmann inversion.

Findings

Optimal reaction coordinates are identified for various molecular symmetries.

Tabulated pair interactions are minimal and memory-efficient.

A step-by-step computational recipe for effective potential derivation is provided.

Abstract

We investigate and provide optimal sets of reaction coordinates for mixed pairs of molecules displaying polar, uniaxial, or spherical symmetry in two and three dimensions. These coordinates are non-redundant, i.e., they implicitly involve the molecules' symmetries. By tabulating pair interactions in these coordinates, resulting tables are thus minimal in length and require a minimal memory space. The intended fields of application are computer simulations of large ensembles of molecules or colloids with rather complex interactions in a fluid or liquid crystalline phase at low densities. Using effective interactions directly in the form of tables can help bridging the time and length scales without introducing errors stemming from any modeling procedure. Finally, we outline an exemplary computational methodology for gaining an effective pair potential in these coordinates, based on the Boltzmann inversion principle, by providing a step-by-step recipe.