Need help in scripts of fix deformation with kim potentials in lammps

OpenKIM
1

Hi, all,

I’m a lammps beginner especially in using kim potentials. I’m currently investigating unaxial tension of a Au-Ag NW. And for this binary system, seldom potentials avaliable online. So, I came OpenKim for help in using kim potentials. My lammps scripts below are good for eam potential, but when I shift to kim models, the compute stress command seems invalid and keeping constant value.

Please help me to figure out the errors!
kim_init EMT_Asap_Standard_JacobsenStoltzeNorskov_1996_AlAgAuCuNiPdPt__MO_115316750986_001 metal
boundary p s s
atom_style atomic
dimension 3

read_data S1G9.lmp

mass 1 196.96656900 # Au
mass 2 107.86820000 # Ag

kim_interactions Au Ag
#pair_style eam/alloy
#pair_coeff * * CuAgAu_Zhou04.eam.alloy Au Ag

compute stress all stress/atom NULL
compute sxx all reduce sum c_stress[1]
variable stress equal c_sxx/(16.9610^4count(all))
thermo_style custom step temp epair etotal press vol lx v_stress

neighbor 0.3 bin
neigh_modify every 1 delay 1

velocity all create 300.0 49284
thermo 5000
fix 1 all nve
fix 2 all temp/rescale 100 300.0 300.0 0.1 0.5
run 50000
unfix 1
unfix 2
write_data NW-nve.data

reset_timestep 0
thermo 5000
fix 1 all npt temp 300.0 300.0 0.1 x 0.0 0.0 0.1
run 50000
unfix 1
write_data NW-npt.data

shell mkdir tensile
shell cd tensile

reset_timestep 0
thermo 2000
timestep 0.001

fix A all nvt temp 300.0 300.0 0.1 drag 1.5
fix ten all deform 1 x erate 0.001 units box

dump 1 all cfg 1000 AuAg..cfg mass type xs ys zs id type*
run 150000

undump 1
unfix ten
unfix A
shell cd …
print “All done!”

Thank you all!

2

I recategorized your post since this is more an OpenKIM question than a LAMMPS question.

3

Thank you for the recategorization.

The scripts work well with EAM potential. It’s so strange it does not work with kim models.

4

It is not strange at all. With KIM models, you import the computation from a separate code base into LAMMPS. The LAMMPS part of this is just the interfacing and copying the information between LAMMPS and the KIM-API. Thus this needs some assessment of an OpenKIM developer.

5

Thank you Axel!
It seems there is a bug in kim informations with previous LAMMPS versions. I fixed it by updating LAMMPS to a new version 29Sep2021. And the problem has been fixed.

Thank you all!
Wish this will help others who encounter the same issue.