Emergence of molecular friction in liquids: bridging between the atomistic and hydrodynamic pictures

Abstract

Friction in liquids arises from conservative forces between molecules and atoms. Although the hydrodynamics at the nanoscale is subject of intense research and despite the enormous interest in the non-Markovian dynamics of single molecules and solutes, the onset of friction from the atomistic scale so far could not be demonstrated. Here, we fill this gap based on frequency-resolved friction data from high-precision simulations of three prototypical liquids, including water. Combining with rigorous theoretical arguments, we show that friction in liquids emerges abruptly at a characteristic frequency, beyond which viscous liquids appear as non-dissipative, elastic solids; as a consequence, its origin is non-local in time. Concomitantly, the molecules experience Brownian forces that display persistent correlations and long-lasting memory. A critical test of the generalised Stokes-Einstein relation, mapping the friction of single molecules to the viscoelastic response of the macroscopic sample, disproves the relation for Newtonian fluids, but substantiates it exemplarily for water and a moderately supercooled liquid. The employed approach is suitable to yield novel insights into vitrification mechanisms and the intriguing mechanical properties of soft materials.

References in corpus (10)

• Anomalous transport in the crowded world of biological cells
• Mean first-passage times of non-Markovian random walkers in confinement
• Iterative Reconstruction of Memory Kernels
• Crossover in the Slow Decay of Dynamic Correlations in the Lorentz Model
• On the "generalized Generalized Langevin Equation"
• Length scale dependence of the Stokes-Einstein and Adam-Gibbs relations in model glass formers
• Parametrizing linear generalized Langevin dynamics from explicit molecular dynamics simulations
• Space-resolved dynamics of a tracer in a disordered solid
• Persistent anti-correlations in Brownian dynamics simulations of dense colloidal suspensions revealed by noise suppression
• Long-time limit of correlation functions

Cited by in corpus (10)

• Open Systems out of Equilibrium: Theory and Simulation
• Finite-size corrections for the static structure factor of a liquid slab with open boundaries
• Molecular origin of driving-dependent friction in fluids
• Fluid flow inside slit-shaped nanopores: the role of surface morphology at the molecular scale
• Shear and bulk acceleration viscosities in simple fluids
• Jerky chiral active particles
• Nonequilibrium friction and free energy estimates for kinetic coarse-graining -- Driven particles in responsive media
• Response of fluorescent molecular rotors in ternary macromolecular mixtures
• Weak-Memory Dynamics in Discrete Time
• Subcritical Pitchfork Bifurcation Transition of a Single Nanoparticle in Strong Confinement