Document Type
Article
Publication Date
2005
Publication Title
The Journal of Chemical Physics
Abstract
We describe a regularized and renormalized electrostatic coupling Hamiltonian for hybrid quantum-mechanical (QM)–molecular-mechanical (MM) calculations. To remedy the nonphysical QM/MM Coulomb interaction at short distances arising from a point electrostatic potential (ESP) charge of the MM atom and also to accommodate the effect of polarized MM atom in the coupling Hamiltonian, we propose a partial-wave expansion of the ESP charge and describe the effect of a s-wave expansion, extended over the covalent radius rc, of the MM atom. The resulting potential describes that, at short distances, large scale cancellation of Coulomb interaction arises intrinsically from the localized expansion of the MM point charge and the potential self-consistently reduces to 1∕rc at zero distance providing a renormalization to the Coulomb energy near interatomic separations. Employing this renormalized Hamiltonian, we developed an interface between the Car-Parrinello molecular-dynamics program and the classical molecular-dynamics simulation program Groningen machine for chemical simulations. With this hybrid code we performed QM/MM calculations on water dimer, imidazole carbon monoxide (CO) complex, and imidazole-heme-CO complex with CO interacting with another imidazole. The QM/MM results are in excellent agreement with experimental data for the geometry of these complexes and other computational data found in literature.
Recommended Citation
Biswas, Pradip K. and Gogonea, Valentin, "A Regularized and Renormalized Electrostatic Coupling Hamiltonian for hybrid Quantum-Mechanical–Molecular-Mechanical Calculations" (2005). Chemistry Faculty Publications. 300.
https://engagedscholarship.csuohio.edu/scichem_facpub/300
DOI
10.1063/1.2064907
Version
Publisher's PDF
Publisher's Statement
© 2005 American Institute of Physics.
Volume
123
Issue
16
Comments
This work was financially supported by the Department of Energy (Grant No. DE-FG02-03ER15462) and the National Institutes of Health (Grant No. 1R15GM070469-01).