The Anisotropic Free Energy of the Lennard-Jones Crystal-Melt Interface

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2003-08-01
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Morris, James
Song, Xueyu
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Ames National Laboratory

Ames National Laboratory is a government-owned, contractor-operated national laboratory of the U.S. Department of Energy (DOE), operated by and located on the campus of Iowa State University in Ames, Iowa.

For more than 70 years, the Ames National Laboratory has successfully partnered with Iowa State University, and is unique among the 17 DOE laboratories in that it is physically located on the campus of a major research university. Many of the scientists and administrators at the Laboratory also hold faculty positions at the University and the Laboratory has access to both undergraduate and graduate student talent.

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Chemistry

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The Department of Chemistry was founded in 1880.

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1880-present

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Ames National LaboratoryChemistry
Abstract

We have calculated the free energy of the crystal-melt interface for the Lennard-Jones system as a function of crystal orientation, near zero pressure, by examining the roughness of the interface using molecular dynamic simulations. The anisotropy is weak, but can be accurately resolved using this approach due to the sensitivity of the fluctuations on the anisotropy. We find that the anisotropy can be described well using two parameters, based upon a low-order expansion satisfying cubic symmetry. The results are in good agreement with previous calculations of the free energies, based upon simulations used to calculate the reversible work required to create the interfaces. The weak anisotropy is also in reasonable agreement: The work here and the work of Davidchack and Laird [R. L. Davidchack and B. B. Laird, J. Chem. Phys. 118, 7651 (2003)] both predict γ100>γ110>γ111. The only discrepancy is that we find a smaller value for the difference γ100−γ111 by an amount larger than the combined error bars.

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The following article appeared in Journal of Chemical Physics 116 (2003): 3920, doi:10.1063/1.1591725.

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Wed Jan 01 00:00:00 UTC 2003
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