Revisting Lennard Jones, Morse, and N-M potentials for metals

DW Jacobson and GB Thompson, COMPUTATIONAL MATERIALS SCIENCE, 205, 111206 (2022).

DOI: 10.1016/j.commatsci.2022.111206

A significant source of error was found in the paper by Zhen and Davies which is highly cited for use in calculating Lennard Jones N-M potential parameters. This error was corrected for and a new more easily implemented method for determining N-M parameters was developed. N-M parameters for 38 metallic elements were calculated using this new method in addition to Morse and Lennard Jones 6-12 parameters. Molecular dynamics simulations were carried out to illustrate the increased accuracy of the new parameters. The predicted bulk modulus of silver using Zhen and Davies parameters was off by approximately 40%, while the bulk modulus calculated using the parameters generated in this study was within 2% of the experimental value. Finally, a discussion on the limitations of each potential type for describing different metallic systems is presented. In particular, the overly slow decay rate of the N-M potential with distance is addressed for small values of parameter "m".

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