Structural relaxation in the hydrogen-bonding liquids n-methylacetamide and water studied by optical kerr effect spectroscopy

D.A. Turton, K. Wynne

Research output: Contribution to journalArticle

56 Citations (Scopus)

Abstract

Structural relaxation in the peptide model N-methylacetamide (NMA) is studied experimentally by ultrafast optical Kerr effect spectroscopy over the normal-liquid temperature range and compared to the relaxation measured in water at room temperature. It is seen that in both hydrogen-bonding liquids, beta relaxation is present, and in each case, it is found that this can be described by the Cole-Cole function. For NMA in this temperature range, the alpha and beta relaxations are each found to have an Arrhenius temperature dependence with indistinguishable activation energies. It is known that the variations on the Debye function, including the Cole-Cole function, are unphysical, and we introduce two general modifications: One allows for the initial rise of the function, determined by the librational frequencies, and the second allows the function to be terminated in the alpha relaxation. (c) 2008 American Institute of Physics.
LanguageEnglish
Pages154516
JournalJournal of Chemical Physics
Volume128
Issue number15
DOIs
Publication statusPublished - 21 Apr 2008

Fingerprint

Optical Kerr effect
Structural relaxation
Kerr effects
Hydrogen bonds
Spectroscopy
Water
Liquids
hydrogen
liquids
water
spectroscopy
Temperature
peptides
Physics
Activation energy
activation energy
temperature dependence
Peptides
physics
temperature

Keywords

  • mode-coupling theory
  • low-frequency modes
  • dielectric-relaxation
  • raman-spectroscopy
  • intermolecular dynamics
  • supercooled liquids
  • molecular liquids
  • light-scattering
  • ionic liquids
  • glass-formers
  • hydrogen bonds
  • librational states
  • liquid structure
  • optical Kerr effect

Cite this

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title = "Structural relaxation in the hydrogen-bonding liquids n-methylacetamide and water studied by optical kerr effect spectroscopy",
abstract = "Structural relaxation in the peptide model N-methylacetamide (NMA) is studied experimentally by ultrafast optical Kerr effect spectroscopy over the normal-liquid temperature range and compared to the relaxation measured in water at room temperature. It is seen that in both hydrogen-bonding liquids, beta relaxation is present, and in each case, it is found that this can be described by the Cole-Cole function. For NMA in this temperature range, the alpha and beta relaxations are each found to have an Arrhenius temperature dependence with indistinguishable activation energies. It is known that the variations on the Debye function, including the Cole-Cole function, are unphysical, and we introduce two general modifications: One allows for the initial rise of the function, determined by the librational frequencies, and the second allows the function to be terminated in the alpha relaxation. (c) 2008 American Institute of Physics.",
keywords = "mode-coupling theory, low-frequency modes, dielectric-relaxation, raman-spectroscopy, intermolecular dynamics, supercooled liquids, molecular liquids, light-scattering, ionic liquids, glass-formers, hydrogen bonds, librational states, liquid structure, optical Kerr effect",
author = "D.A. Turton and K. Wynne",
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language = "English",
volume = "128",
pages = "154516",
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Structural relaxation in the hydrogen-bonding liquids n-methylacetamide and water studied by optical kerr effect spectroscopy. / Turton, D.A.; Wynne, K.

In: Journal of Chemical Physics, Vol. 128, No. 15, 21.04.2008, p. 154516.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Structural relaxation in the hydrogen-bonding liquids n-methylacetamide and water studied by optical kerr effect spectroscopy

AU - Turton, D.A.

AU - Wynne, K.

PY - 2008/4/21

Y1 - 2008/4/21

N2 - Structural relaxation in the peptide model N-methylacetamide (NMA) is studied experimentally by ultrafast optical Kerr effect spectroscopy over the normal-liquid temperature range and compared to the relaxation measured in water at room temperature. It is seen that in both hydrogen-bonding liquids, beta relaxation is present, and in each case, it is found that this can be described by the Cole-Cole function. For NMA in this temperature range, the alpha and beta relaxations are each found to have an Arrhenius temperature dependence with indistinguishable activation energies. It is known that the variations on the Debye function, including the Cole-Cole function, are unphysical, and we introduce two general modifications: One allows for the initial rise of the function, determined by the librational frequencies, and the second allows the function to be terminated in the alpha relaxation. (c) 2008 American Institute of Physics.

AB - Structural relaxation in the peptide model N-methylacetamide (NMA) is studied experimentally by ultrafast optical Kerr effect spectroscopy over the normal-liquid temperature range and compared to the relaxation measured in water at room temperature. It is seen that in both hydrogen-bonding liquids, beta relaxation is present, and in each case, it is found that this can be described by the Cole-Cole function. For NMA in this temperature range, the alpha and beta relaxations are each found to have an Arrhenius temperature dependence with indistinguishable activation energies. It is known that the variations on the Debye function, including the Cole-Cole function, are unphysical, and we introduce two general modifications: One allows for the initial rise of the function, determined by the librational frequencies, and the second allows the function to be terminated in the alpha relaxation. (c) 2008 American Institute of Physics.

KW - mode-coupling theory

KW - low-frequency modes

KW - dielectric-relaxation

KW - raman-spectroscopy

KW - intermolecular dynamics

KW - supercooled liquids

KW - molecular liquids

KW - light-scattering

KW - ionic liquids

KW - glass-formers

KW - hydrogen bonds

KW - librational states

KW - liquid structure

KW - optical Kerr effect

UR - http://dx.doi.org/10.1063/1.2897432

U2 - 10.1063/1.2897432

DO - 10.1063/1.2897432

M3 - Article

VL - 128

SP - 154516

JO - Journal of Chemical Physics

T2 - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 15

ER -