An alternative construction of the Ewald sum |
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Authors: | Robert D. Skeel |
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Affiliation: | 1. Department of Computer Science, Purdue University, West Lafayette, IN, USArskeel@purdue.edu |
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Abstract: | Periodicity is a popular way to handle boundaries in atomistic simulations in the bulk. However, slowly decaying Coulomb interactions lead to ill-defined energies and forces. The Ewald sum is a common way of giving meaning to these terms, but its derivation, based on Fourier series, is not transparent. Described in this article is a derivation based on the limiting behaviour as the cutoff goes to infinity of a truncated and shifted Coulomb potential. This observation strengthens the case for the use of the original Ewald sum. And such a construction may offer advantages for computation and/or modelling. |
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Keywords: | Ewald sum periodic boundaries Coulomb interactions |
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