Impact of Short-Range Forces on Defect Production from High-Energy Collisions.
Primary radiation damage formation in solid materials typically involves collisions between atoms that have up to a few hundred keV of kinetic energy. During these collisions, the distance between two colliding atoms can approach 0.05 nm. At such small atomic separations, force fields fitted to equilibrium properties tend to significantly underestimate the potential energy of the colliding dimer. To enable molecular dynamics simulations of high-energy collisions, it is common practice to use a screened Coulomb force field to describe the interactions and to smoothly join this to the equilibrium force field at a suitable interatomic spacing. However, there is no accepted standard method for choosing the parameters used in the joining process, and our results prove that defect production is sensitive to how the force fields are linked. A new procedure is presented that involves the use of ab initio calculations to determine the magnitude and spatial dependence of the pair interactions at intermediate distances, along with systematic criteria for choosing the joining parameters. Results are presented for the case of nickel, which demonstrate the use and validity of the procedure.
Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Stoller
IMS Lab, Institute of Technology, University of Tartu , 50411 Tartu, Estonia.|Materials Science and Technology Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87544, United States.
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Tamm
Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Béland
Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Samolyuk
Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Stocks
Materials Science and Technology Division, Los Alamos National Laboratory , Los Alamos, New Mexico 87544, United States.
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Caro
Department of Chemistry, Purdue University , West Lafayette, Indiana 47906, United States.
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Slipchenko
Materials Science and Technology Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Osetsky
IMS Lab, Institute of Technology, University of Tartu , 50411 Tartu, Estonia.
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Aabloo
Department of Physics and Astronomy, Uppsala University , SE-75120 Uppsala, Sweden.
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Klintenberg
Pittsburgh Supercomputer Center, Carnegie-Mellon University , Pittsburgh, Pennsylvania 15213, United States.
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Wang