Long Wavelength Thermal Density Fluctuations in Molecular and Polymer Glass-Forming Liquids: Experimental and Theoretical Analysis under Isobaric Conditions

2021 ◽  
Author(s):  
Baicheng Mei ◽  
Yuxing Zhou ◽  
Kenneth S. Schweizer
Keyword(s):  
Theoretical Analysis ◽  
Density Fluctuations ◽  
Long Wavelength ◽  
Glass Forming ◽  
Polymer Glass

scholarly journals Mermin–Wagner fluctuations in 2D amorphous solids

2017 ◽  
Vol 114 (8) ◽  
pp. 1856-1861 ◽  
Author(s):  
Bernd Illing ◽  
Sebastian Fritschi ◽  
Herbert Kaiser ◽  
Christian L. Klix ◽  
Georg Maret ◽  
...  
Keyword(s):  
Computer Simulations ◽  
System Size ◽  
Amorphous Solids ◽  
Two Dimensions ◽  
Density Fluctuations ◽  
Long Wavelength ◽  
Broken Symmetries ◽  
Lindemann Criterion ◽  
The Mean ◽  
2D Crystals

In a recent commentary, J. M. Kosterlitz described how D. Thouless and he got motivated to investigate melting and suprafluidity in two dimensions [Kosterlitz JM (2016)J Phys Condens Matter28:481001]. It was due to the lack of broken translational symmetry in two dimensions—doubting the existence of 2D crystals—and the first computer simulations foretelling 2D crystals (at least in tiny systems). The lack of broken symmetries proposed by D. Mermin and H. Wagner is caused by long wavelength density fluctuations. Those fluctuations do not only have structural impact, but additionally a dynamical one: They cause the Lindemann criterion to fail in 2D in the sense that the mean squared displacement of atoms is not limited. Comparing experimental data from 3D and 2D amorphous solids with 2D crystals, we disentangle Mermin–Wagner fluctuations from glassy structural relaxations. Furthermore, we demonstrate with computer simulations the logarithmic increase of displacements with system size: Periodicity is not a requirement for Mermin–Wagner fluctuations, which conserve the homogeneity of space on long scales.

Density fluctuations around the glass-transition of low molecular weight glass-forming liquids

1991 ◽  
Vol 131-133 ◽  
pp. 134-138 ◽  
Author(s):  
E.W Fischer ◽  
G Meier ◽  
T Rabenau ◽  
A Patkowski ◽  
W Steffen ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Glass Transition ◽  
Density Fluctuations ◽  
Low Molecular Weight ◽  
Glass Forming

scholarly journals Nonclassical Kinetics in Constrained Geometries: Initial Distribution Effects

1998 ◽  
Vol 08 (05) ◽  
pp. 853-868 ◽  
Author(s):  
K. Lindenberg ◽  
A. H. Romero ◽  
J. M. Sancho
Keyword(s):  
Initial Density ◽  
Reaction Diffusion ◽  
Initial Distribution ◽  
Density Fluctuations ◽  
Time Behavior ◽  
Numerical Work ◽  
Irreversible Reaction ◽  
Long Wavelength ◽  
Reaction Diffusion Model

We present a detailed study of the effects of the initial distribution on the kinetic evolution of the irreversible reaction A+B→0 in one dimension. Our analytic as well as numerical work is based on a reaction–diffusion model of this reaction. We focus on the role of initial density fluctuations in the creation of the macroscopic patterns that lead to the well-known kinetic anomalies in this system. In particular, we discuss the role of the long wavelength components of the initial fluctuations in determining the long-time behavior of the system. We note that the frequently studied random initial distribution is but one of a variety of possible distributions leading to interesting anomalous behavior. Our discussion includes an initial distribution with correlated A-B pairs and one in which the initial distribution forms a fractal pattern. The former is an example of a distribution whose long wavelength components are suppressed, while the latter exemplifies one whose long wavelength components are enhanced, relative to those of the random distribution.

Initial Distribution Effects on Diffusion-Limited Reactions in Constrained Geometries

1996 ◽  
Vol 464 ◽  
Author(s):  
Katja Lindenberg ◽  
A. H. Romero ◽  
J. M. Sancho
Keyword(s):  
Initial Density ◽  
Initial Distribution ◽  
Anomalous Behavior ◽  
Density Fluctuations ◽  
Low Dimensions ◽  
Long Wavelength ◽  
Diffusion Limited ◽  
The Creation ◽  
Initial Distributions

ABSTRACTWe present a study of the effects of the initial distribution on the kinetic evolution of irreversible binary reactions in low dimensions. We focus on the role of initial density fluctuations and, in particular, on the role of the long wavelength components of the initial fluctuations, in the creation of the macroscopic patterns that lead to the well-known kinetic anomalies in this system. The frequently studied random initial distribution is but one of a variety of possible distributions leading to interesting anomalous behavior. Our discussion includes initial distributions that suppress and ones that enhance the initial long wavelength components.

Dynamics of density fluctuations of a glass-forming epoxy resin revealed by Brillouin light scattering

1999 ◽  
Vol 59 (2) ◽  
pp. 1899-1907 ◽  
Author(s):  
D. Fioretto ◽  
L. Comez ◽  
G. Socino ◽  
L. Verdini ◽  
S. Corezzi ◽  
...  
Keyword(s):  
Light Scattering ◽  
Epoxy Resin ◽  
Density Fluctuations ◽  
Brillouin Light Scattering ◽  
Glass Forming
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