Transferability and Nonbond Functional Form of Coarse
Grained Force Field – Tested on Linear Alkanes
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Abstract
Whether
or not a coarse grained force field (CGFF) can be made
to be transferrable is an important question to be addressed. By comparing
potential energy with potential of mean force (PMF) of a molecular
dimer, we proposed to use a free energy function (FE-12-6) with the
parameters in entropic and energetic terms explicitly to represent
the nonbond interactions in CGFF. Although the FE-12-6 function cannot
accurately describe the PMF curves, a cancelation of short radii and
strong repulsion makes the function a good approximation. For nonpolar
molecules represented by linear alkanes, FE-12-6 is demonstrated to
be highly effective in representing the nonbond interactions in CGFF.
The force field parameters are well transferrable among different
alkane molecules, in different thermodynamic states and for predicting
various thermodynamic properties including heats of vaporization,
vapor–liquid-equilibrium coexistence curves, surface tensions,
and liquid densities