Dynamic density functional theory versus kinetic theory of simple fluids

Abstract

By combining methods of kinetic and density functional theory, we present a description ofmolecular fluids which accounts for their microscopic structure and thermodynamicproperties as well as their hydrodynamic behavior. We focus on the evolution ofthe one-particle phase space distribution, rather than on the evolution of theaverage particle density which features in dynamic density functional theory. Theresulting equation can be studied in two different physical limits: diffusive dynamics,typical of colloidal fluids without hydrodynamic interaction where particles aresubject to overdamped motion resulting from coupling with a solvent at rest, andinertial dynamics, typical of molecular fluids. Finally, we propose an algorithmto solve numerically and efficiently the resulting kinetic equation by employinga discretization procedure analogous to the one used in the lattice Boltzmannmethod.