Sn MEAM potential

LAMMPS LAMMPS Mailing List Mirror
1

Hello,

I would like to use meam potentials for tin(Sn) to simulation the surface diffusion, but I have trouble with choosing the potentials.

There is one meam potential for Sn in the library.meam, but I can not find where the parameters come from. In the update notes, Greg Wagner (Sandia) wrote that he changed the library “mainly to reproduce some of the results published by Byeong-Joo Lee for second-neighbor MEAM”. But the Sn meam potential of such second-neighbor did not published yet. So I wonder to know the accuracy of the Sn potential in library.meam and where it comes from. What’s more, it is different from the parameters in Ravelo and Baskes. Equilibrium and Thermodynamic Properties of Liquid Tin. 1997. Phys Rev. Lett.

Thanks very much

Wei

2

Greg can likely answer this (CCd).

Steve

3

Hi Wei,

The update notes you're referring to are talking about changes to the MEAM code library, with some new options for the form of the potential to match the formulation used by B-J Lee in his papers. Those changes have nothing to do with Sn or the library.meam file, and I'm sorry for any confusion. I don't make changes to the library.meam file, and I don't have any experience with the potential for Sn.

I'll repeat here the disclaimer I've written in this forum before: The library.meam file is provided as an example, and is meant to be used with care. To understand it, you need to understand it's history: basically, it's the file that Mike Baskes provided with his original MEAM code. Mike and his collaborators edited it along the way, without providing any references; the version included with lammps is just a snapshot of the file at one point during the development of these various codes.

So, if you find other values for these parameters in the literature, by all means feel free to change them -- just make sure you understand any differences between the MEAM formulation coded in lammps and the one in your reference. For example, pay attention to the effects of the augt1 parameter. You can read about that parameter and others on the pair-meam page of the lammps documentation.

Regards,
Greg

4

Thanks so much for your reply and information! It is really helpful.

I would like to read more carefully about the meam document and set up the parameters from the literature.

Best,

Wei

2012/8/27 Wagner, Gregory J <gjwagne@…3…>