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"Utilizing Fast Multipole Expansions for Efficient and Accurate Quantum-Classical Molecular Dynamics Simulations" Magnus Schwörer, Konstantin Lorenzen, Gerald Mathias, and Paul Tavan J. Chem. Phys. 142, 104108 (2015) Abstract: Recently, a novel approach to quantum-classical molecular dynamics (MD) simulations has been suggested [Schwörer et al. J. Chem. Phys. 138, 244103 (2013)]. Here, the forces acting on the atoms are calculated by grid-based density functional theory (DFT) for a solute molecule and by a polarizable molecular mechanics (PMM) force field for a large solvent environment composed of several 103-10 molecules as negative gradients of a DFT/PMM hybrid Hamiltonian. The electrostatic interactions are efficiently described by a hierarchical fast multipole method (FMM). Adopting recent progress of this FMM technique [Lorenzen et al. J. Chem. Theory Comput. 10, 3244 (2014)], which particularly entails a strictly linear scaling of the computational effort with the system size, and adapting this revised FMM approach to the computation of the interactions between the DFT and PMM fragments of a simulation system, here we show how one can further enhance the efficiency and accuracy of such DFT/PMM-MD simulations. The resulting gain of total performance, as measured for alanine dipeptide (DFT) embedded in water (PMM) by the product of the gains in efficiency and accuracy, amounts to about one order of magnitude. We also demonstrate that the jointly parallelized implementation of the DFT and PMM-MD parts of the computation enables the ecient use of high-performance computing systems. The associated software is available online. BMO authors (in alphabetic order): Konstantin Lorenzen Gerald Mathias Magnus Schwörer Paul Tavan  WWW-Version |