[lammps-users] calculation of centro-symmetry parameter

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1

Dear all,

I am now running a simulation with MEAM potential. During the calculation i need the centro-symmetry parameter to check the location where dislocation occurs. Normally, the centro-symmetry parameter for disloaction is 2 and above 20 for surface atoms. But the centro-symmetry parameter i get from dump file are abnormal. Even for the surface atoms, the centro-symmetry parameters are too small.

In order to check my system, I used EAM for the same system again and this time the centro-symmetry parameter were all fine.

Could you please kindly tell me whether the centro-symmetry parameter is related to the potential i use? I think it shoule only related to the geometric condition of the system?

By the way, the version of lammps i use is 22Jun-2007

Thanks a lot!

Regards
Yi

2

Can you try this with the most current (fully patched) version, 4 Dec 07.

The only difference for compute centro between EAM and MEAM should
be the cutoff used. As long as the MEAM cutoff is long enough
to have 12 neighbors/atom, which is all that the centro calc uses,
it should get similar answers.

Steve