title: TINKTEP: A fully self-consistent, mutually polarizable QM/MM approach based on the AMOEBA force field.
abstract: We present a novel quantum mechanical/molecular mechanics (QM/MM) approach in which a quantum subsystem is coupled to a classical subsystem described by the AMOEBA polarizable force field. Our approach permits mutual polarization between the QM and MM subsystems, effected through multipolar electrostatics. Self-consistency is achieved for both the QM and MM subsystems through a total energy minimization scheme. We provide an expression for the Hamiltonian of the coupled QM/MM system, which we minimize using gradient methods. The QM subsystem is described by the onetep linear-scaling DFT approach, which makes use of strictly localized orbitals expressed in a set of periodic sinc basis functions equivalent to plane waves. The MM subsystem is described by the multipolar, polarizable force field AMOEBA, as implemented in tinker. Distributed multipole analysis is used to obtain, on the fly, a classical representation of the QM subsystem in terms of atom-centered multipoles. This auxiliary representation is used for all polarization interactions between QM and MM, allowing us to treat them on the same footing as in AMOEBA. We validate our method in tests of solute-solvent interaction energies, for neutral and charged molecules, demonstrating the simultaneous optimization of the quantum and classical degrees of freedom. Encouragingly, we find that the inclusion of explicit polarization in the MM part of QM/MM improves the agreement with fully QM calculations.
authors: School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom.
authors: Jacek
authors: J
authors: Dziedzic
authors: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors: Yuezhi
authors: Y
authors: Mao
authors: Q-Chem Inc., 6601 Owens Drive, Suite 105, Pleasanton, California 94588, USA.
authors: Yihan
authors: Y
authors: Shao
authors: Department of Chemistry, Washington University in St. Louis, St. Louis, Missouri 63130, USA.
authors: Jay
authors: J
authors: Ponder
authors: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors: Teresa
authors: T
authors: Head-Gordon
authors: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors: Martin
authors: M
authors: Head-Gordon
authors: School of Chemistry, University of Southampton, Highfield, Southampton SO17 1BJ, United Kingdom.
authors: Chris-Kriton
authors: CK
authors: Skylaris