Softened electrostatic molecular potentials

Electrostatic molecular potentials (EMPs) are studied from two points of view. First, a softened EMP (SEMP) approach is proposed, consisting in the substitution of a positive point charge as the entity with which an electronic density function (DF) interacts electrostatically to generate a classical EMP for a Gaussian charge distribution. Second, the performance of this SEMP approach under the Atomic Shell Approximation (ASA) is described and compared with classical EMP at the same ASA level. Several sample applications are presented to describe the general features of this new method of studying electrostatic interactions in molecules. The net result is a family of SEMPs that encompass EMPs as special cases but do not possess their infinite discontinuities. The features of SEMPs are quite similar to those of EMPs distant from nuclei, and the absence of infinity values makes them good candidates to be employed in molecular similarity calculations.

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► A method to override systematic poles is described.
► It constitutes a method to simplify EMP visualizations.
► Within the ASA, the calculations are simple and only require the evaluation of the error function.
► The molecular surface can be easily treated a posteriori with other methods and purposes (for visualization, gridding, integration, similarity comparisons, etc.).