Atoms moving too far in a lattice while minimizing energy

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1

Hi All,

I am trying to find a minimum energy configuration for a lattice. I am giving a text file with atom-id, type and x,y,z coordinates as input. After running the simulation for minimizing the energy using harmonic bonds and angles, I am using dump to output the final coordinates in a text file. But the difference between the initial and final coordinates are in some cases even more than 20 angstroms ! This is of course undesirable for a lattice to have such a huge deformation .

Can I set a limit for the overall maximum translation (not the maximum translation in a step) while doing the minimization, or is there any other solution to this problem ?

Thanks

Here is my LAMMPS script:

#----------- Initialize Simulation ---------------------
clear
units metal
dimension 3
boundary f f f
atom_modify sort 0 0
atom_style angle
bond_style harmonic
angle_style harmonic

#----------- Create Atoms ---------------------
read_data input.txt

#-------------Set dump-------------------------
dump myDump all atom 10000 result.txt
dump_modify myDump scale no

#-------------Run Minimization-----------------
reset_timestep 0
min_style sd
min_modify dmax 0.2
minimize 1e-25 1e-25 5000 10000

print “All done!”

input.txt (134 KB)

2

This is due to bad initial configuration. Try this using a simple geometry with few bonds only, and then see by increasing the system size.

sagar