Dresden 2003 – wissenschaftliches Programm
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M: Metallphysik
M 15: Symposium: Phasenumwandlungen in Schmelzen V
M 15.3: Vortrag
Dienstag, 25. März 2003, 10:45–11:00, IFW A
Phase Behavior and Dynamics of a Symmetrical Lennard–Jones Mixture: Computer Simulations — •Jürgen Horbach, Subir Das, and Kurt Binder — Institut für Physik, Johannes Gutenberg–Universität, Staudinger Weg 7, D–55099 Mainz
A combination of Monte Carlo (MC) and Molecular Dynamics (MD) computer simulation techniques is used to study the structure and dynamics of a symmetrical, binary Lennard–Jones mixture (єAA=єBB=1.0, єAB=0.5, σAA=σBB=σAB=1.0). The simulations are done at constant density ρ=1.0 where the system is in the liquid state and does not show any tendencies to crystallize at the temperatures under consideration (T ≥ 1.0). The idea is to start with MC simulations in the semigrand canonical ensemble in order to calculate the T–xA phase diagram (xA: concentration of A particles), i.e. the fluid–fluid coexistence curve. As a “byproduct” fully equilibrated configurations at coexistence are obtained which are the starting point for microcanonical MD simulations to calculate structural quantities such as different static structure factors, transport coefficients such as the self and interdiffusion constants, the shear and the bulk viscosity and time dependent correlation functions such as the intermediate scattering functions. For the determination of transport properties also Non–Equilibrium MD techniques are applied. We show that the dynamics exhibits nontrivial features close to and at coexistence that can be described by a subtle interplay of density and concentration fluctuations.