Analytical First Derivatives of the RE-squared Interaction Potential

TL;DR

This paper derives exact force and torque expressions for biaxial molecules with the RE-squared potential, improving simulation efficiency and enabling faster molecular dynamics simulations compared to finite difference methods.

Contribution

It provides exact analytical derivatives for the RE-squared potential and efficient routines that significantly speed up rigid body MD simulations.

Findings

1.6 times speedup over finite difference methods

MD simulation time comparable to MC simulation

Exact expressions improve simulation accuracy

Abstract

We derive exact expressions for the forces and torques between biaxial molecules interacting via the RE-squared potential, a recent variant of the Gay-Berne potential. Moreover, efficient routines have been provided for rigid body MD simulations, resulting in 1.6 times speedup compared to the two-point finite difference approach. It has also been shown that the time cost of a MD simulation will be almost equal to a similar MC simulation, making use of the provided routines.