Reconsidering
Dispersion Potentials: Reduced Cutoffs
in Mesh-Based Ewald Solvers Can Be Faster Than Truncation
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Abstract
Long-range dispersion interactions
have a critical influence on
physical quantities in simulations of inhomogeneous systems. However,
the perceived computational overhead of long-range solvers has until
recently discouraged their implementation in molecular dynamics packages.
Here, we demonstrate that reducing the cutoff radius for local interactions
in the recently introduced particle–particle particle−mesh
(PPPM) method for dispersion [Isele-Holder et al., <i>J. Chem.
Phys.</i>, <b>2012</b>, <i>137</i>, 174107] can
actually often be faster than truncating dispersion interactions.
In addition, because all long-range dispersion interactions are incorporated,
physical inaccuracies that arise from truncating the potential can
be avoided. Simulations using PPPM or other mesh Ewald solvers for
dispersion can provide results more accurately and more efficiently
than simulations that truncate dispersion interactions. The use of
mesh-based approaches for dispersion is now a viable alternative for
all simulations containing dispersion interactions and not merely
those where inhomogeneities were motivating factors for their use.
We provide a set of parameters for the dispersion PPPM method using
either <i>i</i><b>k</b> or analytic differentiation
that we recommend for future use and demonstrate increased simulation
efficiency by using the long-range dispersion solver in a series of
performance tests on massively parallel computers