Berlin 2012 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 19: Computational Materials Modelling IV - Finite Temperature

MM 19.5: Vortrag

Dienstag, 27. März 2012, 11:15–11:30, TC 006

Wall-liquid and wall-crystal interfacial excess free energies via thermodynamic integration: A molecular dynamics simulation study — •Ronald Benjamin and Juergen Horbach — Institut für Theoretische Physik II, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany

A method is proposed to compute the wall-liquid and wall-crystal interfacial excess free energy by molecular dynamics simulation. Our approach is based on a thermodynamic integration scheme, where the wall-liquid (or wall-crystal) interaction potential is gradually modified so that we move from a reference state of known interfacial energy to the state of interest and then computing the difference in the Gibbs excess free energy. We test our method by applying it to a Lennard Jones (LJ) system in contact with a wall, which is either flat or structured. The flat wall is modeled by a WCA potential and the structured wall consists of a few layers of particles rigidly fixed at the sites of an ideal fcc crystal lattice and interacting with the liquid (crystal) via the LJ potential. The interfacial excess energy is also determined from the stress anisotropy and we find good agreement between the two approaches.