Document Type
Article
Publication Date
2008
Publication Title
The Journal of Chemical Physics
Abstract
We present an ab initio polarizable representation of classical molecular mechanics (MM) atoms by employing an angular momentum-based expansion scheme of the point charges into partial wave orbitals. The charge density represented by these orbitals can be fully polarized, and for hybrid quantum-mechanical-molecular-mechanical (QM/MM) calculations, mutual polarization within the QM/MM Hamiltonian can be obtained. We present the mathematical formulation and the analytical expressions for the energy and forces pertaining to the method. We further develop a variational scheme to appropriately determine the expansion coefficients and then validate the method by considering polarizations of ions by the QM system employing the hybrid GROMACS-CPMD QM/MM program. Finally, we present a simpler prescription for adding isotropic polarizability to MM atoms in a QM/MM simulation. Employing this simpler scheme, we present QM/MM energy minimization results for the classic case of a water dimer and a hydrogen sulfide dimer. Also, we present single-point QM/MM results with and without the polarization to study the change in the ionization potential of tetrahydrobiopterin (BH(4)) in water and the change in the interaction energy of solvated BH(4) (described by MM) with the P(450) heme described by QM. The model can be employed for the development of an extensive classical polarizable force-field.
Recommended Citation
Biswas, P. K. and Gogonea, Valentin, "A Polarizable Force-Field Model for Quantum-Mechanical-Molecular-Mechanical Hamiltonian Using Expansion of Point Charges Into Orbitals" (2008). Chemistry Faculty Publications. 299.
https://engagedscholarship.csuohio.edu/scichem_facpub/299
DOI
10.1063/1.2992527
Version
Publisher's PDF
Volume
129
Issue
15
Comments
The authors acknowledge the financial support from the Department of Energy Grant No. DE-FG02-03ER15462, the National Institutes of Health Grant No. 1R15GM070469-01, and the National Center on Minority Health and Health Disparities Grant No. P20MD002725, and Computational support from the National Center for Supercomputer Applications NCSA at University of Illinois and Ohio Supercomputer Center, OH.