Departmental Papers (MEAM)

Document Type

Journal Article

Date of this Version

February 2004

Comments

Postprint version. Published in Journal of Chemical Physics, Volume 120, Issue 8, 22 February 2004, pages 3841-3846.
Publisher URL: http://dx.doi.org/10.1063/1.1643725

Abstract

Thermal expansion and impurity effects on the lattice thermal conductivity of solid argon have been investigated with equilibrium molecular dynamics simulation. Thermal conductivity is simulated over the temperature range of 20 – 80 K. Thermal expansion effects, which strongly reduce thermal conductivity, are incorporated into the simulations using experimentally measured lattice constants of solid argon at different temperatures. It is found that the experimentally measured deviations from a T-1 high-temperature dependence in thermal conductivity can be quantitatively attributed to thermal expansion effects. Phonon scattering on defects also contributes to the deviations. Comparison of simulation results on argon lattices with vacancy and impurity defects to those predicted from the theoretical models of Klemens and Ashegi et al. demonstrates that phonon scattering on impurities due to lattice strain is stronger than that due to differences in mass between the defect and the surrounding matrix. In addition, the results indicate the utility of molecular dynamics simulation for determining parameters in theoretical impurity scattering models under a wide range of conditions. It is also confirmed from the simulation results that thermal conductivity is not sensitive to the impurity concentration at high temperatures.

Keywords

Thermal expansion, Equilibrium molecular dynamics, Thermal conductivity

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Date Posted: 21 January 2006

This document has been peer reviewed.