MS21-P06 New models of electron density for electrostatic interaction energy estimation Slawomir Bojarowski (University of Warsaw, Faculty of Chemistry, Warsaw, Poland) Paulina M. Dominiak (University of Warsaw, Faculty of Chemistry, Warsaw, Poland) Prashant Kumar (University of Warsaw, Faculty of Chemistry, Warsaw, Poland) Claudia M. Wandtke (Institut fur Anorganische Chemie Georg-August-Universitat, Goetingen, Germany) Birger Dittrich (Anorganische Chemie und Strukturchemie, Heinrich-Heine Universitat, Dusseldorf, Germany)email: sbojarowski@chem.uw.edu.plThe accurate estimation of electrostatic interaction energies in a reasonable time is a still challenging task. The simple summation of multipole moments is fast, but it does not account the penetration energy (Epen). The Epen can be up to 50% of total electrostatic interaction energy (Ees) at the equilibrium distance.

Our concept is taken from the theoretical crystallography. We applied aspherical pseudoatom databank (University at Buffalo DataBank - UBDB)  which can easily reproduce the averaged electron density and calculate the Ees. We also tested reproduced electron densities from a new algorithm of refinement procedure, which differs from this commonly used in the databanks. However, the best performance is achieved when the promolecule model of an electron density is augmented by point charges fitted to electrostatic potential (RESP). It enables estimation of the exact electrostatic interaction energy and, by its simplicity, it allows to omit computational-costly integration procedure. Our recent researches show that the RESP charges can be successfully replaced by the point charges from other - easy attainable - sources: from database or from semiempirical methods. 
 
We would like to acknowledge the National Science Centre for PRELUDIUM-UMO/2015/19/N/ST4/00010 grant.
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Keywords: electrostatic interaction energy, penetration effects