scholarly journals Effect of physical aging on the low-frequency vibrational density of states of a glassy polymer

2003 ◽  
Vol 63 (5) ◽  
pp. 778-784 ◽  
Author(s):  
E Duval ◽  
L Saviot ◽  
L David ◽  
S Etienne ◽  
J. F Jal
Keyword(s):  
Density Of States ◽  
Physical Aging ◽  
Glassy Polymer ◽  
Low Frequency ◽  
Vibrational Density Of States ◽  
Vibrational Density

scholarly journals Universal law for the vibrational density of states of liquids

2021 ◽  
Vol 118 (5) ◽  
pp. e2022303118
Author(s):  
Alessio Zaccone ◽  
Matteo Baggioli
Keyword(s):  
Density Of States ◽  
Normal Modes ◽  
Low Frequency ◽  
Average Lifetime ◽  
Vibrational Density Of States ◽  
Lennard Jones ◽  
Average Relaxation Time ◽  
Universal Law ◽  
Infinite Set ◽  
Vibrational Density

An analytical derivation of the vibrational density of states (DOS) of liquids, and, in particular, of its characteristic linear in frequency low-energy regime, has always been elusive because of the presence of an infinite set of purely imaginary modes—the instantaneous normal modes (INMs). By combining an analytic continuation of the Plemelj identity to the complex plane with the overdamped dynamics of the INMs, we derive a closed-form analytic expression for the low-frequency DOS of liquids. The obtained result explains, from first principles, the widely observed linear in frequency term of the DOS in liquids, whose slope appears to increase with the average lifetime of the INMs. The analytic results are robustly confirmed by fitting simulations data for Lennard-Jones liquids, and they also recover the Arrhenius law for the average relaxation time of the INMs, as expected.

scholarly journals Anomalies in the low frequency vibrational density of states for a polymer with intrinsic microporosity – the Boson peak of PIM-1

2018 ◽  
Vol 20 (3) ◽  
pp. 1355-1363 ◽  
Author(s):  
Reiner Zorn ◽  
Huajie Yin ◽  
Wiebke Lohstroh ◽  
Wayne Harrison ◽  
Peter M. Budd ◽  
...  
Keyword(s):  
Density Of States ◽  
Low Frequency ◽  
Boson Peak ◽  
Vibrational Density Of States ◽  
First Time ◽  
Intrinsic Microporosity ◽  
Vibrational Density

For the first time the low frequency vibrational density of states is reported for a polymer with intrinsic microporosity.

scholarly journals Excess vibrational density of states and the brittle to ductile transition in crystalline and amorphous solids

Soft Matter ◽  
2016 ◽  
Vol 12 (4) ◽  
pp. 1210-1218 ◽  
Author(s):  
Jeetu S. Babu ◽  
Chandana Mondal ◽  
Surajit Sengupta ◽  
Smarajit Karmakar
Keyword(s):  
Mechanical Loading ◽  
Density Of States ◽  
Amorphous Solids ◽  
Vibrational Density Of States ◽  
Brittle To Ductile Transition ◽  
Active Research ◽  
Vibrational Density

The conditions which determine whether a material behaves in a brittle or ductile fashion on mechanical loading are still elusive and comprise a topic of active research among materials physicists and engineers.

Low-energy vibrational density of states of plasticized poly(methyl methacrylate)

2002 ◽  
Vol 82 (5) ◽  
pp. 533-539 ◽  
Author(s):  
L. Saviot ◽  
E. Duval ◽  
J. F. Jal ◽  
A. J. Dianoux ◽  
V. A. Bershtein ◽  
...  
Keyword(s):  
Methyl Methacrylate ◽  
Density Of States ◽  
Low Energy ◽  
Vibrational Density Of States ◽  
Poly Methyl Methacrylate ◽  
Vibrational Density
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