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DY: Fachverband Dynamik und Statistische Physik
DY 22: Poster: Statistical Physics
DY 22.5: Poster
Mittwoch, 19. März 2025, 10:00–12:00, P3
Diffusion and order in mixed lattice gas of hard squares — •Piotr Nowakowski1, Niklas Raake2, and Ana-Sunčana Smith2,1 — 1Institut Ruđer Bošković, Zagreb, Croatia — 2Friedrich–Alexander–Universität Erlangen–Nürnberg, Erlangen, Germany
We study the diffusion in a crowded environment using a model system of a lattice gas composed of hard square particles of 1× 1 and 2× 2 size (measured in lattice constant units) undergoing a Brownian motion on a two-dimensional square lattice. For the whole range of concentrations of both types of particles, we numerically test the accuracy and efficiency of an approximation of the motion by a persistent random walk with one or two step memory. A good agreement is observed for very low and very high concentrations of particles.
Additionally, we look at the second order phase transition from a gas phase for low densities of 2× 2 particles to a columnar phase. Surprisingly, it seems that the density of large particles at which the transition occurs is not affected by the presence of smaller particles. Moreover, in columnar phase the diffusion constant can be approximated by studying a one-dimensional system.
Keywords: diffusion; random walk; lattice gas; kinetic Monte Carlo; two-dimensional system