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Re: [lammps-users] Mixing EAM potentilas to create alloy potential in LAMMPS
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Re: [lammps-users] Mixing EAM potentilas to create alloy potential in LAMMPS


From: Julien Guénolé <julien.guenole@...4839...>
Date: Thu, 21 Dec 2017 11:33:52 +0100

12/17 06:31, ankur agrawal wrote:
Hello
I am facing a problem in making a alloy EAM potential for Ni-Co by using the individual element EAM potentials from NIST database, and merging them using averaging of phi interactions
I have attached the 2 individual EAM potential files. For combining them, I copy pasted them one below the another. Another thing that I kept in mind was that the Nr phi terms were removed from their place in individual potentials and added at last along with phi 2-1 calculated by averaging in excel.

merging potentials is not a kind of a black magic... I'll be surprise that a "simple" copy-paste + averaging will ever give you a decent physical result!

One of the problems is that in this setfl format, we are allowed to specify Npho, dpho, Nr and dr only once in the beginning. They will be same for all the elements present.
But, the individual files for Ni and Co that are available on NIST have different values of these distances  dr and dpho. In these case how to mix these potentials?
For time being I just used the values of Co in the file, but I am getting errors ( lost atoms) while relaxing the alloy structure. I think this is a bad potential that I have created.

most probably

Can somebody please guide me on mixing EAM potentials to create alloy potential?

Do you have a paper describing such a procedure? Then follow it.

Btw, generating new potentials is a (very) complex task, that can take years! This is not something that has to be on a mailing list. Discuss with your supervisor(s), teacher or colleagues who have already an experience in this task.

Julien.

Yours Sincerely
Ankur Agrawal
FifthYear Dual Degree Student
Department of Chemical Engineering
Indian Institute of Technology, kanpur, India

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