I have a couple of questions regarding the implementation of the tabulated file for copper per Mishin et. al. Phys. Rev. B. (2001).
From what I understand, the pair-potential is directly calculated in the scheme employed by the authors of the article, and LAMMPS takes in electron charge values and determines the pair-potential values. To make that conversion to create a file for LAMMPS, one has to take the square root of the pair-potential values given by Mishin.
But, I was looking at the tables on their website and I see that some of the values for the pair-potential are -ve.
In the tabulated file that comes with the LAMMPS standard download, I see that the -ve values were all set to zero. Could you please tell me if that is correct and that is the case, do you know of any accuracy issues as a consequence of making them zero.
Also, could anyone please tell me the source of Universal 4.0 and Universal 3.0 Cu EAM files?
Thank you for your time and patience in answering my queries.
Department of Chemical Engineering
University of Massachusetts,
Amherst MA 01003