Viscosity coefficients and the phonon density temperature dependence in liquid 4He

The nuclear quadrupolar spin-lattice relaxation times T1 have been calculated in alkali halides, whereby the phonon densities of states have been extracted from the shell model lattice dynamics. The calculations at room temperature were performed on 79Br in KBr, NaBr, and RbBr; 23Na in NaI, NaCl, and NaBr; 35Cl in NaCl and KCl; and 127I in NaI and KI. The obtained values of relaxation time T1 are an order of magnitude smaller than those calculated with the Debye-model phonon density of states and agree well with experiments. The temperature dependence of acoustic and optical phonon contributions to the nuclear relaxation rate (first-order Raman phonon process) are carried out in the temperature range 20 to 300 K for 23Na and 127I in NaI. The role of optical phonons becomes important from 77 K on; the temperature dependence of T1 agrees with experimental data throughout most of the temperature range studied (77–300 K), while differing quantitatively from the predictions obtained on the basis of the Debye model.

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Universal temperature dependence of the thermal conductivity and viscosity coefficients

International Journal of Heat and Mass Transfer ◽

10.1016/0017-9310(92)90325-m ◽

1992 ◽

Vol 35 (11) ◽

pp. 3059-3067 ◽

Cited By ~ 3

Author(s):

A.S. Okhotin ◽

L.I. Zhmakin ◽

A.P. Ivanyuk

Keyword(s):

Thermal Conductivity ◽

Temperature Dependence ◽

Viscosity Coefficients

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Parameterization of the temperature dependence of the Debye–Waller factors

Acta Crystallographica Section A Foundations of Crystallography ◽

10.1107/s0108767399005176 ◽

1999 ◽

Vol 55 (5) ◽

pp. 926-932 ◽

Cited By ~ 98

Author(s):

H. X. Gao ◽

L.-M. Peng

Keyword(s):

Temperature Dependence ◽

Shell Model ◽

Density Of States ◽

Phonon Density ◽

Phonon Density Of States ◽

Acta Cryst ◽

Model Calculations ◽

Debye Approximation ◽

Zinc Blende ◽

Zinc Blende Structure

Parameterization has been made for the temperature dependence of the Debye–Waller factors of 68 elemental crystals and 17 compounds with the zinc-blende structure. The Debye–Waller factors of 46 elemental crystals were calculated based on the available phonon density of states, and those of the remaining 22 elemental crystals were estimated using the Debye approximation for the phonon density of states. The Debye–Waller factors of the zinc-blende compounds were obtained from the 14-parameter shell-model calculations of Reid [Acta Cryst. (1983), A39, 1–13].

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Phonon Density of States Reconstruction of the Temperature Dependence of Heat Capacity Ferroelectrics Sn 2 P 2 Se(S) 6 Crystals

Ferroelectrics ◽

10.1080/00150190211225 ◽

2002 ◽

Vol 270 (1) ◽

pp. 369-374 ◽

Cited By ~ 1

Author(s):

V. M. Rizak ◽

I. M. Rizak ◽

O. I. Lendyel ◽

V. V. Maslyuk

Keyword(s):

Heat Capacity ◽

Temperature Dependence ◽

Density Of States ◽

Phonon Density ◽

Phonon Density Of States

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Application of Nuclear Inelastic Scattering Spectroscopy to the Frequency Scale Calibration of Ab Initio Calculated Phonon Density of States of Quasi-One-Dimensional Ternary Iron Chalcogenide RbFeSe2

Applied Sciences ◽

10.3390/app10207212 ◽

2020 ◽

Vol 10 (20) ◽

pp. 7212

Author(s):

Airat Kiiamov ◽

Vladimir Tsurkan ◽

Dorina Croitori ◽

Hans-Albrecht Krug von Nidda ◽

Zakir Seidov ◽

...

Keyword(s):

Inelastic Scattering ◽

Ab Initio ◽

Temperature Dependence ◽

Density Of States ◽

Nuclear Inelastic Scattering ◽

Phonon Density ◽

Phonon Density Of States ◽

One Dimensional ◽

Frequency Scale ◽

Frequency Correction

This study aims to examine the applicability of nuclear inelastic scattering (NIS) and conventional Mössbauer spectroscopy for calibration of the frequency scale of ab initio calculated phonon density of states (PDOS) of iron ternary chalcogenides. NIS measurements are carried out on the quasi-one-dimensional ternary chalcogenide RbFeSe2 to obtain the partial PDOS of the iron atoms in the compound. We compare the experimental PDOS with our previous results on vibrational properties of RbFeSe2 obtained with density functional theory (DFT) ab initio calculations, conventional Mössbauer, and infra-red spectroscopies. The experimental PDOS measured by NIS is collated with the ab initio calculated one. The frequency correction factor for the ab initio results is determined as 1.077, in good agreement with value of 1.08 obtained previously from the temperature dependence of the Lamb–Mössbauer factor of the iron atoms in RbFeSe2. We conclude that nuclear inelastic scattering and temperature dependence of the Lamb–Mössbauer factor in conventional Mössbauer spectroscopy can be equally applied for evaluation of the frequency correction factor for ab initio calculated phonon density of iron of ternary chalcogenides.

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