title: Extension of adaptive tree code and fast multipole methods to high angular momentum particle charge densities.
abstract: The development and implementation of a tree code (TC) and fast multipole method (FMM) for the efficient, linear-scaling calculation of long-range electrostatic interactions of particle distributions with variable shape and multipole character are described. The target application of these methods are stochastic boundary molecular simulations with polarizable force fields and/or combined quantum mechanical/molecular mechanical potentials. Linear-scaling is accomplished through the adaptive decomposition of the system into a hierarchy of interacting particle sets. Two methods for effecting this decomposition are evaluated: fluc-splitting and box-splitting, for which the latter is demonstrated to be generally more accurate. In addition, a generalized termination criterion is developed that delivers optimal performance at fixed error tolerance that, in the case of quadrupole-represented Drude water, effects a speed-up by a factor of 2-3 relative to a multipole-independent termination criteria. The FMM is shown to be approximately 2-3 times faster than the TC, independent of the system size and multipole order of the particles. The TC and FMM are tested for a variety of static and polarizable water systems, and for the the 70S ribosome functional complex containing an assembly of transfer and messenger RNAs.
authors.affiliation: Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, USA.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Giese
authors.forename: Darrin M
authors.initials: DM
authors.lastname: York
mesh_terms: D019295:Computational Biology; D046911:Macromolecular Substances / Q000737:chemistry*; D008962:Models, Theoretical; D010316:Particle Size; D012270:Ribosomes / Q000737:chemistry; D055672:Static Electricity
chemical_list: D046911:Macromolecular Substances