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CPP: Chemische Physik und Polymerphysik

CPP 5: SYMPOSIUM: Dynamics of multi-component fluids POSTER

CPP 5.25: Poster

Friday, March 4, 2005, 17:15–19:00, Poster TU D

Coarse-Graining of non-bonded molecules? — •Sabine H.L. Klapp¹, Henry Bock², and Keith E Gubbins² — ¹Stranski-Laboratorium für Physikalische und Theoretische Chemie, Sekr. TC7, Technische Universität Berlin, Strasse des 17. Juni 124, 10623 Berlin, Germany — ²Department of Chemical Engineering, North Carolina State University, 113 Riddick Labs, Raleigh, NC 27695-7905, USA

In coarse–grained ("mesoscale") computer simulations of complex mixtures, such as surfactants in aqueous solution, two routes are generally followed: the first route consists of considering only the motion of the surfactant molecules and integrating out the water completely. The water is then treated only implicitly via the effective potential between surfactants. The other possibility, which is the one commonly used in Dissipative particle dynamics (DPD) simulations, is to keep explicit "beads" containing several non–bonded water molecules. In this contribution we demonstrate, based on exact expressions for effective potentials, that coarse–graining of non–bonded molecules such as water does not work in the sense that the corresponding effective potential vanishes.