Electrostatic potentials and free energies of solvation of polar and charged molecules

Gerhard Hummer; Lawrence R. Pratt; Angel E. Garcia; Bruce J. Berne; Steven W. Rick

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arXiv · physics/9704020

Electrostatic potentials and free energies of solvation of polar and charged molecules

Gerhard Hummer·Lawrence R. Pratt·Angel E. Garcia·Bruce J. Berne·Steven W. Rick

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Abstract

Theories of solvation free energies often involve electrostatic potentials at the position of a solute charge. Simulation calculations that apply cutoffs and periodic boundary conditions based on molecular centers result in center-dependent contributions to electrostatic energies due to a systematic sorting of charges in radial shells. This sorting of charges induces a surface-charge density at the cutoff sphere or simulation-box boundary that depends on the choice of molecular centers. We identify a simple solution that gives correct, center-independent results, namely the radial integration of charge densities. Our conclusions are illustrated for a Lennard-Jones solute in water. The present results can affect the parameterization of force fields.

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Gerhard Hummer, Lawrence R. Pratt, Angel E. Garcia, Bruce J. Berne, Steven W. Rick. 1997-04-16. Electrostatic potentials and free energies of solvation of polar and charged molecules. https://arxiv.org/abs/physics/9704020

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