Related Experiment Video
Updated: Mar 8, 2026
11:03
An Analog Macroscopic Technique for Studying Molecular Hydrodynamic Processes in Dense Gases and Liquids
Published on: December 4, 2017
9.1K
Probing heterogeneous dynamics from spatial density correlation in glass-forming liquids
Yan-Wei Li1, You-Liang Zhu1, Zhao-Yan Sun2
1State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Physical Review. E
|January 14, 2017
Summary
Spatial density correlations, specifically cluster size of densely packed particles (DPPs), reveal dynamical heterogeneity in glass-forming liquids. Particle mobility depends on repulsive interactions, influencing dynamics during relaxation.
Area of Science:
- Condensed Matter Physics
- Computational Materials Science
- Statistical Mechanics
Background:
- Dynamical heterogeneity is a key feature of glass-forming liquids.
- Understanding the link between structure and dynamics is crucial for glass science.
- Traditional pair correlation functions may not fully capture complex dynamics.
Purpose of the Study:
- To investigate the relationship between spatial density correlation and dynamical heterogeneity.
- To evaluate the efficacy of cluster size of densely packed particles (DPPs) versus pair correlation functions.
- To explore model-dependent dynamics in glass-forming liquids.
Main Methods:
- Numerical simulations of glass-forming liquids.
- Analysis of spatial density correlations using DPP cluster size.
- Comparison of particle mobility in Lennard-Jones and Weeks-Chandler-Andersen models.
- Investigation of particle hopping dynamics.
Main Results:
- DPP cluster size effectively differentiates dynamics between LJ and WCA models.
- High local density correlates with slow dynamics for hard repulsions and mobile dynamics for soft repulsions.
- Model-dependent dynamics are linked to DPP hopping motion during the caging stage.
Conclusions:
- DPP cluster size is a superior metric for dynamical heterogeneity compared to pair correlation functions.
- Repulsive interaction nature significantly impacts the relationship between local density and particle mobility.
- Hopping dynamics of DPPs, influenced by particle compressibility, govern relaxation behavior in different models.
Related Concept Videos
01:18First Law: Particles in Two-dimensional Equilibrium
16.9K
Recall that a particle in equilibrium is one for which the external forces are balanced. Static equilibrium involves objects at rest, and dynamic equilibrium involves objects in motion without acceleration; but it is important to remember that these conditions are relative. For instance, an object may be at rest when viewed from one frame of reference, but that same object would appear to be in motion when viewed by someone moving at a constant velocity.
Newton's first law tells us about...
Newton's first law tells us about...
16.9K
01:17Viscosity
7.7K
When water is poured into a glass, it falls freely and quickly, whereas if honey or maple syrup is poured over a pancake, it flows slowly and sticks to the surface of the container. This difference in the flow of different kinds of liquids arises due to the fluid friction between the liquid layers and the liquid and the surrounding material. This property of fluids is called fluid viscosity. In this example, water has a lower viscosity than honey and maple syrup.
The SI unit of viscosity is...
The SI unit of viscosity is...
7.7K
01:29Nonideal Two-Component Liquid Solutions
26
Nonideal liquid solutions, also known as real solutions, do not strictly follow Raoult's law. Raoult's law is a rule of thumb in physical chemistry. However, not all mixtures adhere to this law due to varying molecular interactions. For example, in an acetone/chloroform solution, the individual vapor pressures of the components are lower than expected, resulting in a total vapor pressure below that predicted by Raoult's law, causing a negative deviation.On the other hand, in an ethanol/water...
26
01:19Viscosity of Fluid
1.6K
Viscosity measures the resistance a fluid offers to flow and deformation. It results from internal friction between layers of fluid moving relative to one another. Dynamic viscosity, denoted by the Greek letter mu (μ), quantifies the force needed to move one fluid layer over another. For Newtonian fluids like water and air, the relationship between the shearing stress and the rate of shearing strain is linear, meaning their viscosity remains constant regardless of the applied stress.
1.6K
01:10First Law: Particles in One-dimensional Equilibrium
8.3K
Newton's first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a net external force. It also states that there must be a cause for any change in velocity (a change in either magnitude or direction) to occur. This cause is a net external force. For example, consider what happens to an object sliding along a rough horizontal surface. The object quickly grinds to a halt, due to the net force of friction. If...
8.3K
00:56Density
20.3K
Density is an important characteristic of substances, crucial in determining whether an object sinks or floats in a fluid. Its SI unit is kg/m3, and its cgs unit is g/cm3. The density of an object helps in identifying its composition, and also reveals information about the phase of the matter and its substructure. The densities of liquids and solids are roughly comparable, consistent with the fact that their atoms are in close contact. However, gases have much lower densities than liquids and...
20.3K