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MM: Fachverband Metall- und Materialphysik

MM 7: Computational Materials Modelling - Methods

MM 7.2: Vortrag

Montag, 11. März 2013, 12:00–12:15, H24

An Approach to Coarse-Grained Molecular Dynamics — •David Edmunds, Paul Tangney, Dimitri Vvedensky, and Matthew Foulkes — Imperial College London, London, UK

Traditional molecular dynamics (MD) simulations provide an effective method for simulating the evolution of a system at the atomic level, without the associated computational cost of ab-initio methods such as density-functional theory. However, many physical and biological processes occur on length scales of millimetres and time scales of seconds, which remain out of reach to fully atomistic simulations on even the most powerful modern supercomputers.

Fortunately, a family of techniques known as coarse-grained molecular dynamics (CGMD) exists, which can bridge the gap between atomistic simulation and the mesoscale. These approaches allow for a larger time step to be used, as the fast degrees of freedom in the system have effectively been integrated out. They can also produce CG potentials which are much less computationally intensive than their all-atom counterparts. This results in CG simulations which are several orders of magnitude faster than all-atom MD, allowing the simulation of billion atom systems on standard desktop computers.

We present two strategies for deriving a coarse-grained pairwise interaction potential, based on the internal energy and free energy of a pair of constrained molecules. We benchmark these methods against a fully atomistic MD simulation of interacting C60 buckyballs, chosen since they are trivially represented by a single CG site located at their centre of mass.