Related Experiment Video
Updated: Jun 16, 2026

An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
Fragility, Stokes-Einstein violation, and correlated local excitations in a coarse-grained model of an ionic liquid
Daun Jeong1, M Y Choi, Hyung J Kim
1Department of Chemistry, Seoul National University, Seoul 151-747, Korea.
Abstract:
Dynamics of a coarse-grained model for the room-temperature ionic liquid, 1-ethyl-3-methylimidazolium hexafluorophosphate, couched in the united-atom site representation are studied via molecular dynamics simulations. The dynamically heterogeneous behavior of the model resembles that of fragile supercooled liquids. At or close to room temperature, the model ionic liquid exhibits slow dynamics, characterized by nonexponential structural relaxation and subdiffusive behavior. The structural relaxation time, closely related to the viscosity, shows a super-Arrhenius behavior. Local excitations, defined as the displacement of an ion exceeding a threshold distance, are found to be mainly responsible for structural relaxation in the alternating structure of cations and anions. As the temperature is lowered, excitations become progressively more correlated. This results in the decoupling of exchange and persistence times, reflecting a violation of the Stokes-Einstein relation.
More Related Videos
Related Concept Videos
Imperfections in Crystal Structure: Stoichiometric Point Defects
Theories of Dissolution: The Danckwerts' Model and Interfacial Barrier Model
Molecular and Ionic Solids
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Entropy and Solvation
Fluid Mosaic Model
Fluid Mosaic Model

