The ultrafast dynamics of hydrogen-bonded liquids: Molecular structure-dependent occurrence of normal arrhenius or fractional Stokes-Einstein-Debye rotational diffusive relaxation

Neil T. Hunt, Andrew R. Turner, Hajime Tanaka, Klaas Wynne

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

The ultrafast rotational-diffusive dynamics of the peptide linkage model compounds N-methylacetamide (NMA), acetamide (Ac), and N,N-dimethylacetamide (DMA) have been studied as a function of temperature using optically heterodyne-detected optical Kerr effect (OHD-OKE) spectroscopy. Both NMA and Ac exhibit a non-Arrhenius temperature dependence of the rotational diffusive relaxation time. By contrast, the non-hydrogen-bonding DMA exhibits normal hydrodynamic behavior. The unusual dynamics of NMA and Ac are attributed to the decoupling of single-molecule rotational diffusive relaxation from the shear viscosity via a transition between stick and slip boundary conditions, which arises from local heterogeneity in the liquid due to the formation of hydrogen-bonded chains or clusters. This provides new insight into the structure and dynamics of an important peptide model compound and the first instance of such a phenomenon in a room-temperature liquid. The OHD-OKE responses of carboxylic acids acetic acid (AcOH) and dichloroacetic acid (DCA) are also reported. These, along with the terahertz Raman spectra, show no evidence of the effects observed in amide systems, but display trends consistent with the presence of an equilibrium between the linear and cyclic dimer structures at all temperatures and moderate-to-high mole fractions in aqueous solution. This equilibrium manifests itself as hydrodynamic behavior in the liquid phase.

LanguageEnglish
Pages9634-9643
Number of pages10
JournalJournal of Physical Chemistry B
Volume111
Issue number32
DOIs
Publication statusPublished - 16 Aug 2007

Fingerprint

Molecular structure
Hydrogen
molecular structure
occurrences
Optical Kerr effect
Kerr effects
peptides
Liquids
hydrogen
liquids
hydrodynamics
Peptides
Dichloroacetic Acid
Hydrodynamics
Dichloroacetic acid
display devices
acetic acid
carboxylic acids
linkages
decoupling

Keywords

  • Kerr-effect spectroscopy
  • orientational dynamics
  • 2-Dimentional correlation spectroscopy
  • low frequency spectrum
  • effect OHD-OKE
  • N-Methylacetamide
  • acetic acid
  • isotropic phase
  • AB-initio

Cite this

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title = "The ultrafast dynamics of hydrogen-bonded liquids: Molecular structure-dependent occurrence of normal arrhenius or fractional Stokes-Einstein-Debye rotational diffusive relaxation",
abstract = "The ultrafast rotational-diffusive dynamics of the peptide linkage model compounds N-methylacetamide (NMA), acetamide (Ac), and N,N-dimethylacetamide (DMA) have been studied as a function of temperature using optically heterodyne-detected optical Kerr effect (OHD-OKE) spectroscopy. Both NMA and Ac exhibit a non-Arrhenius temperature dependence of the rotational diffusive relaxation time. By contrast, the non-hydrogen-bonding DMA exhibits normal hydrodynamic behavior. The unusual dynamics of NMA and Ac are attributed to the decoupling of single-molecule rotational diffusive relaxation from the shear viscosity via a transition between stick and slip boundary conditions, which arises from local heterogeneity in the liquid due to the formation of hydrogen-bonded chains or clusters. This provides new insight into the structure and dynamics of an important peptide model compound and the first instance of such a phenomenon in a room-temperature liquid. The OHD-OKE responses of carboxylic acids acetic acid (AcOH) and dichloroacetic acid (DCA) are also reported. These, along with the terahertz Raman spectra, show no evidence of the effects observed in amide systems, but display trends consistent with the presence of an equilibrium between the linear and cyclic dimer structures at all temperatures and moderate-to-high mole fractions in aqueous solution. This equilibrium manifests itself as hydrodynamic behavior in the liquid phase.",
keywords = "Kerr-effect spectroscopy, orientational dynamics, 2-Dimentional correlation spectroscopy, low frequency spectrum, effect OHD-OKE, N-Methylacetamide, acetic acid, isotropic phase, AB-initio",
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year = "2007",
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language = "English",
volume = "111",
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The ultrafast dynamics of hydrogen-bonded liquids: Molecular structure-dependent occurrence of normal arrhenius or fractional Stokes-Einstein-Debye rotational diffusive relaxation. / Hunt, Neil T.; Turner, Andrew R.; Tanaka, Hajime; Wynne, Klaas.

In: Journal of Physical Chemistry B, Vol. 111, No. 32, 16.08.2007, p. 9634-9643.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The ultrafast dynamics of hydrogen-bonded liquids: Molecular structure-dependent occurrence of normal arrhenius or fractional Stokes-Einstein-Debye rotational diffusive relaxation

AU - Hunt, Neil T.

AU - Turner, Andrew R.

AU - Tanaka, Hajime

AU - Wynne, Klaas

PY - 2007/8/16

Y1 - 2007/8/16

N2 - The ultrafast rotational-diffusive dynamics of the peptide linkage model compounds N-methylacetamide (NMA), acetamide (Ac), and N,N-dimethylacetamide (DMA) have been studied as a function of temperature using optically heterodyne-detected optical Kerr effect (OHD-OKE) spectroscopy. Both NMA and Ac exhibit a non-Arrhenius temperature dependence of the rotational diffusive relaxation time. By contrast, the non-hydrogen-bonding DMA exhibits normal hydrodynamic behavior. The unusual dynamics of NMA and Ac are attributed to the decoupling of single-molecule rotational diffusive relaxation from the shear viscosity via a transition between stick and slip boundary conditions, which arises from local heterogeneity in the liquid due to the formation of hydrogen-bonded chains or clusters. This provides new insight into the structure and dynamics of an important peptide model compound and the first instance of such a phenomenon in a room-temperature liquid. The OHD-OKE responses of carboxylic acids acetic acid (AcOH) and dichloroacetic acid (DCA) are also reported. These, along with the terahertz Raman spectra, show no evidence of the effects observed in amide systems, but display trends consistent with the presence of an equilibrium between the linear and cyclic dimer structures at all temperatures and moderate-to-high mole fractions in aqueous solution. This equilibrium manifests itself as hydrodynamic behavior in the liquid phase.

AB - The ultrafast rotational-diffusive dynamics of the peptide linkage model compounds N-methylacetamide (NMA), acetamide (Ac), and N,N-dimethylacetamide (DMA) have been studied as a function of temperature using optically heterodyne-detected optical Kerr effect (OHD-OKE) spectroscopy. Both NMA and Ac exhibit a non-Arrhenius temperature dependence of the rotational diffusive relaxation time. By contrast, the non-hydrogen-bonding DMA exhibits normal hydrodynamic behavior. The unusual dynamics of NMA and Ac are attributed to the decoupling of single-molecule rotational diffusive relaxation from the shear viscosity via a transition between stick and slip boundary conditions, which arises from local heterogeneity in the liquid due to the formation of hydrogen-bonded chains or clusters. This provides new insight into the structure and dynamics of an important peptide model compound and the first instance of such a phenomenon in a room-temperature liquid. The OHD-OKE responses of carboxylic acids acetic acid (AcOH) and dichloroacetic acid (DCA) are also reported. These, along with the terahertz Raman spectra, show no evidence of the effects observed in amide systems, but display trends consistent with the presence of an equilibrium between the linear and cyclic dimer structures at all temperatures and moderate-to-high mole fractions in aqueous solution. This equilibrium manifests itself as hydrodynamic behavior in the liquid phase.

KW - Kerr-effect spectroscopy

KW - orientational dynamics

KW - 2-Dimentional correlation spectroscopy

KW - low frequency spectrum

KW - effect OHD-OKE

KW - N-Methylacetamide

KW - acetic acid

KW - isotropic phase

KW - AB-initio

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DO - 10.1021/jp072409h

M3 - Article

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JO - Journal of Physical Chemistry B

T2 - Journal of Physical Chemistry B

JF - Journal of Physical Chemistry B

SN - 1520-6106

IS - 32

ER -