Molecular Hydrodynamics from Memory Kernels.
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.
École Normale Supérieure, PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Université Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France.
Dominika
D
Lesnicki
École Normale Supérieure, PSL Research University, Département de Chimie, Sorbonne Universités-UPMC Université Paris 06, CNRS UMR 8640 PASTEUR, 24 rue Lhomond, 75005 Paris, France.
Rodolphe
R
Vuilleumier
Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire PHENIX, Case 51, 4 Place Jussieu, F-75005 Paris, France.
Antoine
A
Carof
Sorbonne Universités, UPMC Université Paris 06, CNRS, Laboratoire PHENIX, Case 51, 4 Place Jussieu, F-75005 Paris, France.
Benjamin
B
Rotenberg