  In recent years, molecular dynamics (MD) simulations have emerged as a
pivotal tool for understanding the structure, dynamics, and phase behavior in
charged soft matter systems. To explore phenomena across greater length and
time scales in MD simulations, molecules are often coarse-grained for better
computational performance. However, commonly-used force fields represent
particles as hard-core interaction centers with point charges, which often
overemphasizes the packing effect and short-range electrostatics, especially in
systems with bulky deformable organic molecules and systems with strong
coarse-graining. This underscores the need for an efficient soft-core model to
physically capture the effective interactions between coarse-grained particles.
To this end, we implement a soft-core model uniting the Gaussian core model
with smeared electrostatic interactions that is phenomenologically equivalent
to recent theoretical models. We first parameterize it generically using water
as the model solvent. Then, we benchmark its performance in the OpenMM toolkit
for different boundary conditions to highlight a computational speedup of up to
$34\times$ compared to commonly used force fields and existing implementations.
Finally, we demonstrate its utility by investigating how boundary
polarizability affects the adsorption behavior of a polyelectrolyte solution on
perfectly conducting and nonmetal electrodes.
