The Phase Stacking Diagram of Colloidal Mixtures and the Relation Between Grand Canonical and Canonical Ensembles in Density Functional Theory

When: Thursday, 4th September (2014), 12:00h
Place: Departamento de Física Teórica de la Materia Condensada, Facultad Ciencias, Módulo 5, Aula de Seminarios (5ª Planta).
Speaker: Daniel de las Heras, Universitat Bayreuth, Department of Physics, Germany.

In this talk I will discuss two topics. First I will present the stacking diagram of colloidal mixtures. The observation of stacks of distinct layers in a colloidal mixture in the sedimentation–diffusion equilibrium is a consequence of bulk phase separation. We introduce the Legendre transform of the chemical potential representation of the bulk phase diagram to obtain a unique stacking diagram of all possible stacks under gravity. Simple bulk phase diagrams generically lead to complex stacking diagrams. We extend the Gibbs phase rule to account for the maximum number of stacks that can appear under gravity. The second part of the talk will focus on the relation between grand canonical and canonical ensembles in density functional theory. I will present a general method to obtain the canonical one-body density distributions and the canonical partition functions for a given grand canonical density functional.