#Classical or quantum calculator software#

The development of the series is based on the cluster-expansion formalism applied to the Abe form for p/sup( n/) expressed as a product of the generalized Kirkwood superposition approximation P/sup( n/)/sub K/ and a correction factor exp(A/sup( n/)(1,2.,n)). « lessĪ study is made of a series-expansion procedure which gives the leading terms of the n-particle distribution function p/sup( n/)(1,2.,n) as explicit functionals in the radial distribution function g(r).

#Classical or quantum calculator software#

The associated software is available online. We also demonstrate that the jointly parallelized implementation of the DFT and PMM-MD parts of the computation enables the efficient use of high-performance computing systems. 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.

Adopting recent progress of this FMM technique, 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 electrostatic interactions are efficiently described by a hierarchical fast multipole method (FMM). 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 10 molecules as negative gradients of a DFT/PMM hybrid Hamiltonian. Recently, a novel approach to hybrid quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations has been suggested.