Question about Sn MEAM parameters in library.meam file

Hello all,

This may not me the correct place to ask this, but I was wondering if anyone was aware of the source of the tin (Sn) MEAM parameters in the library.meam file. The comments at the top of the file say it is taken vax files, however I don’t know what this means.
None of the papers cited on the lammps MEAM page seem to have parameters for Tin.

I also did some literature search and found MEAM parameters for Tin in the following paper:
Ravelo and Baskes. Equilibrium and Thermodynamic Properties of Liquid ``Tin. 1997. Phys Rev. Lett.

However none of the parameters in this paper matches up the Tin parameters in library.meam.

Can anyone help?

Thank you,
Joseph Vella
PhD Candidate
Department of Chemical & Biological Engineering

Greg Wagner might be able to answer (CCd).

Steve

Hi Joseph,

The parameters in the library.meam file aren’t meant to be taken as sacrosanct. This file is a snapshot in time of the parameter file that Mike Baskes included with his Dynamo code. Some of these values are well-tested, but others may be things that were being tested at the time this file was originally handed out. Calling this file a “library” was probably a mistake – “example” would be better.

As for the values for Sn, I don’t know where those numbers come from, and if you have values from the literature you’re best off using those. However, you’ll want to be a bit careful with the formulation — not all references use exactly the same formulation of the MEAM potential, and this can lead to modifications in the values (see for example the documentation on the augt1 parameter). At the very least, you may want to verify that you can reproduce some of the published energies for various configurations from the Ravelo paper before moving forward with that parameter set.

Regards,
Greg

Greg Wagner
Manager, Thermal/Fluid Science and Engineering Department
Sandia National Laboratories, Livermore, CA
Tel: (925) 294-2180 Fax: (925) 294-3410
Email: gjwagne@…3…