[lammps-users] NiTi potential

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1

Dear LAMMPS developers,
   I am trying to run an MD simulation for NiTi alloy. I am using an EAM
Finnis-Sinclair type potential taken from literature. However during
thermal equilibration the atoms start to move out of the box. Also the
pressure in thermo ouput is quite high. I am not sure whether the
problem lies with the eam.fs file that I created or with the lattice
structure. I am specifying the lattice and potential in input file as
follows:

lattice bcc 3.02
region box1 block 0 40.0 0 25.0 0 10
create_box 2 box1

create_atoms 2 region box1 basis 1 1
pair_style eam/fs
pair_coeff * * NiTi.eam.fs Ti Ni

The Ti atoms are at the corners while the Ni atoms are at the center of
the BCC structure. Is this correct then?

I am also attaching the EAM potential file. This potential is supposed to
work at 0 K. It will also help if NiTi potential in some other format is
available.

Thanking you,
Arkaprabha

NiTi.eam.fs (318 KB)

2

I don't know anything about your potential, but you want 2 basis
atoms in your lattice. So you want the lattice custom
command, with 2 basis arguments (0,0,0) and (0.5,0.5,0.5).
Then use create_atoms twice, once for the Ti atoms (type 1)
and once for the Ni atoms (type 2).

Steve