Dr. Gianni De Fabritiis
Department of Chemistry
University College of London
London, UK

Monday, November 21, 2005
3:00 pm (CT)
3269 Beckman Institute

Abstract

Large scale molecular simulations are an invaluable computational tool provided an accurate force field is used. However, collective properties emerging at the mesoscale still cannot be studied by MD for many molecular systems. The problem is due to the separation between the time and length scales of the microscopic atomistic description compared to the mesoscopic scales of interest. Many mesoscale modeling techniques have been proposed which attempt to cover these scales by reducing the degrees of freedom of the system coarse-graining the molecular system. This procedure reproduces qualitatively correct mesoscale behavior at the cost of molecular specificity. We propose a computational technique based on a domain decomposition of the molecular system such that the full molecular nature is kept where it is of interest but is coarse-grained anywhere else. We use classical molecular dynamics and a coarse-grained continuum model based on fluctuating hydrodynamics equations which is thermodynamically consistent. For the phenomena to which this decomposition can be applied, such as interfaces, membranes, microfluidics, etc, the procedure provides an efficient computational tool with full molecular specificity. A set of applications is presented and the difficulties in coupling molecular and fluctuating hydrodynamics codes are described. In particular, the lecture will provide some insight into the problem of no slip boundary conditions at hydrophobic, hydrophilic interfaces, represented in our case by a lipid monolayer.