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Energy decomposition in molecular complexes: Implications for the treatment of polarization in molecular simulations

Posted September 5th, 2013 by ccurutchet
TitleEnergy decomposition in molecular complexes: Implications for the treatment of polarization in molecular simulations
Publication TypeJournal Article
Year of Publication2003
AuthorsCurutchet, C, Bofill JM, Hernandez B, Orozco M, Luque FJ
JournalJournal of Computational Chemistry
Volume24
Issue10
Pagination1263 - 1275
Date Published2003
ISBN Number0192-8651
Keywordsab-initio, aqueous-solution, atomic charges, cation-pi interactions, chloroform/water partition-coefficients, electrostatic potentials, energy decomposition, fluctuating charge, force field, force-fields, induction energies, molecular simulation, nucleic-acid bases, polarization
AbstractThis study examines the contribution of electrostatic and polarization to the interaction energy in a variety of molecular complexes. The results obtained from the Kitaura-Morokuma (KM) energy decomposition analysis at the HF/6-31G(d) level indicate that, for intermolecular distances around the equilibrium geometries, the polarization energy can be determined as the addition of the polarization energies of interacting blocks, as the mixed polarization term is typically negligible. Comparison of KM and QM/MM results shows that the electrostatic energy determined in the KM method is underestimated (in absolute value) by QM/MM methods. The reason of such underestimation can be attributed to the simplified representation of treating the interaction between overlapping charge distribution by the interaction of a QM molecule with a set of point charges. Nevertheless, the polarization energies, calculated by KM and QM/MM methods are in close agreement. Finally, a consistent, automated strategy to derive charge distributions that include implicitly polarization effects in pairwise, additive force fields is presented. The strategy relies in the simultaneous fitting of electrostatic and polarization energies computed by placing a suitable perturbing particle at selected points around the molecule.. The suitability of these charges to describe molecular interactions is discussed. (C) 2003 Wiley Periodicals, Inc.