Phys. Rev. Lett – 2016 : Molecular Hydrodynamics from Memory Kernels

Published on : 19/07/2016

Molecular Hydrodynamics from Memory Kernels

by Dominika Lesnicki, Rodolphe Vuilleumier, Antoine Carof and Benjamin Rotenberg

Contact PHENIX : Benjamin Rotenberg

The memory kernel for a tagged particle in a fluid, computed from molecular dynamics simulations, decays algebraically as t−3/2. We show how the hydrodynamic Basset-Boussinesq force naturally emerges from this long-time tail and generalize the concept of hydrodynamic added mass. This mass term is negative in the present case of a molecular solute, which is at odds with incompressible hydrodynamics predictions. Lastly, we discuss the various contributions to the friction, the associated time scales, and the crossover between the molecular and hydrodynamic regimes upon increasing the solute radius.