Role of vibrational modes in structural relaxations in a supercooled liquid

1999 ◽  
Author(s):  
Shankar P. Das ◽  
Sudha Srivastava
Keyword(s):  
Supercooled Liquid ◽  
Vibrational Modes

The Role of Interface Vibrational Modes in Thermal Boundary Resistance

2021 ◽  
Author(s):  
Christopher M. Stanley ◽  
Benjamin K. Rader ◽  
Braxton H. D. Laster ◽  
Mahsa Servati ◽  
Stefan K. Estreicher
Keyword(s):  
Boundary Resistance ◽  
Thermal Boundary Resistance ◽  
Vibrational Modes

The Role of Interface Vibrational Modes in Thermal Boundary Resistance

2021 ◽  
Vol 218 (23) ◽  
pp. 2170063
Author(s):  
Christopher M. Stanley ◽  
Benjamin K. Rader ◽  
Braxton H. D. Laster ◽  
Mahsa Servati ◽  
Stefan K. Estreicher
Keyword(s):  
Boundary Resistance ◽  
Thermal Boundary Resistance ◽  
Vibrational Modes

scholarly journals Ice is born in low-mobility regions of supercooled liquid water

2019 ◽  
Vol 116 (6) ◽  
pp. 2009-2014 ◽  
Author(s):  
Martin Fitzner ◽  
Gabriele C. Sosso ◽  
Stephen J. Cox ◽  
Angelos Michaelides
Keyword(s):  
Liquid Water ◽  
Dynamical Behavior ◽  
Supercooled Liquid ◽  
Ice Nucleation ◽  
Water Molecules ◽  
Ice Crystal ◽  
Surrounding Water ◽  
Dynamical Heterogeneity ◽  
Complex Dynamical Behavior

When an ice crystal is born from liquid water, two key changes occur: (i) The molecules order and (ii) the mobility of the molecules drops as they adopt their lattice positions. Most research on ice nucleation (and crystallization in general) has focused on understanding the former with less attention paid to the latter. However, supercooled water exhibits fascinating and complex dynamical behavior, most notably dynamical heterogeneity (DH), a phenomenon where spatially separated domains of relatively mobile and immobile particles coexist. Strikingly, the microscopic connection between the DH of water and the nucleation of ice has yet to be unraveled directly at the molecular level. Here we tackle this issue via computer simulations which reveal that (i) ice nucleation occurs in low-mobility regions of the liquid, (ii) there is a dynamical incubation period in which the mobility of the molecules drops before any ice-like ordering, and (iii) ice-like clusters cause arrested dynamics in surrounding water molecules. With this we establish a clear connection between dynamics and nucleation. We anticipate that our findings will pave the way for the examination of the role of dynamical heterogeneities in heterogeneous and solution-based nucleation.

Role of dynamic heterogeneities in crystal nucleation kinetics in an oxide supercooled liquid

2016 ◽  
Vol 145 (21) ◽  
pp. 211920 ◽  
Author(s):  
Prabhat K. Gupta ◽  
Daniel R. Cassar ◽  
Edgar D. Zanotto
Keyword(s):  
Supercooled Liquid ◽  
Crystal Nucleation ◽  
Nucleation Kinetics

A role of non-hydrogen framework vibrational modes in formation of ferroelectric properties of H-bonded K3H(SO4)2-like materials

2004 ◽  
Vol 700 (1-3) ◽  
pp. 199-205 ◽  
Author(s):  
S.P. Dolin ◽  
A.A. Levin ◽  
T.Yu. Mikhailova ◽  
N.S. Strokach ◽  
M.V. Solin ◽  
...  
Keyword(s):  
Ferroelectric Properties ◽  
Vibrational Modes

scholarly journals Low-frequency vibrational modes in G-quadruplexes reveal the mechanical properties of nucleic acids

2020 ◽  
Author(s):  
M. González-Jiménez ◽  
G. Ramakrishnan ◽  
K. Wynne
Keyword(s):  
Protein Interactions ◽  
Kerr Effect ◽  
Biological Function ◽  
Low Frequency ◽  
Theoretical Models ◽  
Protein Recognition ◽  
Optical Kerr Effect ◽  
Vibrational Modes ◽  
New Perspective

AbstractLow-frequency vibrations play an essential role in biomolecular processes involving DNA such as gene expression, charge transfer, drug intercalation, and DNA–protein recognition. However, understanding of the vibrational basis of these mechanisms relies on theoretical models due to the lack of experimental evidence. Here we present the low-frequency vibrational spectra of G-quadruplexes (structures formed by four strands of DNA) and B-DNA characterized using femtosecond optical Kerr-effect spectroscopy. Contrary to expectation, we found that G-quadruplexes show several strongly underdamped delocalized phonon-like modes that have the potential to contribute to the biology of the DNA at the atomic level. In addition, G-quadruplexes present modes at a higher frequency than B-DNA demonstrating that changes in the stiffness of the molecule alter its gigahertz to terahertz vibrational profile. These results demonstrate that current theoretical models fail to predict basic properties of the vibrational modes of DNA.Statement of significanceA number of recent studies have identified thermally excited low-frequency vibrational modes as a key deciding factor in the biological function of DNA. However, the nature of these vibrational modes has never been established. Here, vibrational spectroscopy with unrivalled signal-to-noise in the gigahertz to terahertz range is used to determine the low-frequency Raman spectra of nucleotides and oligomeric DNAs carefully chosen to form G-quadruplexes, structures formed by four strands of DNA common in the genome. These G-quadruplexes exhibit an unusual group of highly-underdamped delocalized vibrational modes—not reproduced by any of the theoretical models in use—which are expected to be the thermally excited. This provides a new perspective on the role of low-frequency vibrational modes in protein interactions and allostery.

scholarly journals Fröhlich Systems in Cellular Physiology

2012 ◽  
Vol 113 (2) ◽  
pp. 95-104 ◽  
Author(s):  
Fedor Šrobár
Keyword(s):  
Internal Heat ◽  
Vibrational Modes ◽  
Coupled Vibration ◽  
Higher Order Modes ◽  
Mathematical Formulas ◽  
Present Part ◽  
Diagrammatic Method ◽  
Microscopic Morphology ◽  
Experimental And Theoretical Studies

Electromagnetic fields are usually absent in the picture of processes taking place in living cells which is dominated by biochemistry, molecular genetics and microscopic morphology. Yet experimental and theoretical studies suggest that this omission is not justified. At the end of 1960’s H. Fröhlich elaborated a semi-phenomenological model of polar oscillating units that are metabolically driven, exchange energy with the cell’s internal heat reservoir, and store part of the energy in excited vibrational modes in such way, that mode with the lowest frequency becomes highly excited, while the higher-order modes remain near thermal equilibrium. This affords energy-hungry chemical reactions to take place while the rest of the cell is not exposed to heat stress. At present, part of the cytoskeleton – microtubules – are deemed to fulfil the role of oscillating units. The paper provides an introduction to the Fröhlich ideas for readers with background in medicine and biology in that it avoids mathematical formulas and relies on figures to convey information about the basic properties of the model. The essential features of the Fröhlich model – most notably the energy condensation – are demonstrated on ensemble encompassing three coupled vibration modes that can be exactly described using original diagrammatic method.

scholarly journals The role of vibronic coupling in the electronic spectroscopy of maleimide: a multi-mode and multi-state quantum dynamics study

2020 ◽  
Vol 22 (43) ◽  
pp. 25272-25283
Author(s):  
Andreas Lehr ◽  
Sandra Gómez ◽  
Michael A. Parkes ◽  
Graham A. Worth
Keyword(s):  
Absorption Spectrum ◽  
Electronic Absorption Spectrum ◽  
Excited States ◽  
Electronic Absorption ◽  
Quantum Dynamics ◽  
Electronic Spectroscopy ◽  
Vibrational Modes ◽  
Model Hamiltonian ◽  
Multi Mode

The first two excitation bands below 7 eV in the electronic absorption spectrum of maleimide are investigated using a model Hamiltonian including four low-lying singlet excited states within the manifold of 24 vibrational modes.

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