Anomalous temperature dependence of the low-frequency vibrational density of states in vitreous B2O3

1997 ◽  
Vol 235 (2) ◽  
pp. 169-175 ◽  
Author(s):  
R. Fernández-Perea ◽  
F.J. Bermejo ◽  
A. de Bernabé ◽  
C-K. Loong
Keyword(s):  
Temperature Dependence ◽  
Density Of States ◽  
Low Frequency ◽  
Anomalous Temperature Dependence ◽  
Anomalous Temperature ◽  
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.

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