Regensburg 2016 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 24: Complex Fluids and Colloids IV (joint session BP/CPP/DY, organized by DY)

CPP 24.5: Talk

Tuesday, March 8, 2016, 15:00–15:15, H46

Size matters: can we use a Hamiltonian adaptive resolution scheme to simulate an open system? — •Robinson Cortes-Huerto, Maziar Heidari, and Raffaello Potestio — Max Planck Institute for Polymer Research, Mainz, Germany

Finite size effects are ubiquitous in molecular dynamics simulations. Apart from the obvious implicit size effects due to periodic boundary conditions, explicit size effects are consequence of simulating a fixed and relatively small number of particles. In particular, measurements of density fluctuations within a sub-domain of a periodic simulation box are strongly dependent on the sub-domain size. These effects can be neglected by carrying out computer simulations for extremely large systems. An alternative solution is to use the Hamiltonian adaptive resolution scheme (H-AdResS), where the computational cost reduces substantially by embedding a relatively small high resolution portion of the system in a larger region at low resolution. Our main goal is to explore the viability to perform grand canonical simulations using this dual-resolution approach. In particular, we propose to use H-AdResS to calculate thermodynamic properties of prototypical molecular liquids in an effective open boundary simulation framework. To this end, we calculate Kirkwood-Buff integrals that connect radial distribution functions, available from molecular dynamics simulations, to thermodynamic properties such as the isothermal compressibility. We compare these results with measurements performed in the fully atomistic case and assess whether an adaptive resolution simulation reproduces the behaviour expected from an open simulation setup.