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Author Takahashi, Hideaki ♦ Umino, Satoru ♦ Morita, Akihiro
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ DIAGRAMS ♦ DIMERS ♦ ELECTRON DENSITY ♦ ELECTRONS ♦ HOLES ♦ HYDROGEN ♦ MOLECULES ♦ OXONIUM IONS ♦ POTENTIAL ENERGY ♦ POTENTIALS ♦ QUANTUM MECHANICS ♦ SOLUTES ♦ WATER ♦ WAVE FUNCTIONS
Abstract We developed a simple method to calculate exchange repulsion between a quantum mechanical (QM) solute and a molecular mechanical (MM) molecule in the QM/MM approach. In our method, the size parameter in the Buckingham type potential for the QM solute is directly determined in terms of the one-electron wave functions of the solute. The point of the method lies in the introduction of the exchange core function (ECF) defined as a Slater function which mimics the behavior of the exterior electron density at the QM/MM boundary region. In the present paper, the ECF was constructed in terms of the Becke-Roussel (BR) exchange hole function. It was demonstrated that the ECF yielded by the BR procedure can faithfully reproduce the radial behavior of the electron density of a QM solute. The size parameter of the solute as well as the exchange repulsion are, then, obtained using the overlap model without any fitting procedure. To examine the efficiency of the method, it was applied to calculation of the exchange repulsions for minimal QM/MM systems, hydrogen-bonded water dimer, and H{sub 3}O{sup +}–H{sub 2}O. We found that our approach is able to reproduce the potential energy curves for these systems showing reasonable agreements with those given by accurate full quantum chemical calculations.
ISSN 00219606
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-08-28
Publisher Place United States
Journal Journal of Chemical Physics
Volume Number 143
Issue Number 8


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