How to create initial data for creating of Al2O3 amorphous by lammps?

Dear all,

Could you please explain for me how to create initial data for creating an Al2O3 amorphous by lammps?

Please note that is not really a LAMMPS specific question but a question about general MD simulation procedures.

Amorphous structures for MD are typically created by melting a bulk crystal structure and then quenching and relaxing it.

Crystal structures can be created with the lattice and create_atoms commands or imported from a data file with read_data.

I know what steps for creating of Amorphous structures are:
#####################################
units metal
atom_style atomic

read_data Al2O3.data
replicate 2 2 2
velocity all create 5000 87287

pair_style eam/alloy
pair_coeff * * AlO.eam.alloy Al O

neighbor 2.0 bin
neigh_modify every 1 delay 0 check yes one 1000 page 2000

fix 1 all nvt temp 5000 5000 0.1
fix 2 all deform 1 x final 0 15.70866 y final 0 14.29263 z final 0 18.1387987 units box
thermo 50
thermo_style custom step cpu temp press ke pe etotal vol
thermo_modify lost ignore
dump 1 all atom 1000 dump.lammpstrj
run 500000

unfix 2
unfix 1
fix 1 all nvt temp 5000 3000 0.1
run 500000

unfix 1
fix 1 all nvt temp 3000 3000 0.1
fix 2 all deform 1 x final 0 14.280600 y final 0 12.993300 z final 0 16.489817 units box
run 500000

unfix 1
unfix 2
fix 1 all nvt temp 3000 3000 0.1
run 500000

unfix 1
fix 1 all nvt temp 3000 300 0.1
run 1000000
undump 1

unfix 1
fix 1 all nvt temp 300 300 0.1
dump 1 all atom 1000 dump2.lammpstrj
thermo_style custom step temp density cpu
run 1000000

write_data new_data.txt

But my question is how to create the initial Al2O3.data by Lammps.
I used some software to create it but I want to use just lammps.
Or If there is a way to convert cif file to lammps data?

When you already know that, then why do you ask for it?
Answers to questions can only be as good as the questions. If you don’t provide any information about what parts of the steps required you already know, you have to expect that people answering will assume that you don’t know any of it. So please don’t complain about being told what you already know when you don’t mention that.

See my previous comment. You could have asked this right away.
Nevertheless, I already answered that question. You can build a crystal structure by using the lattice and create_atoms commands. Please see their documentation. How to apply this to your specific case is an exercise for you.

Please also note that LAMMPS is not designed to be a “one stop shop” for all things MD. It is very deliberately designed to by a simulation engine, so its abilities to pre- and post-process data are limited (although not as limited than it was at the beginning a couple of decades ago). For everything else, you need to use pre- or post-processing software. A few links are provided at https://lammps.org/prepost.html but that list is not complete (we are dependent on people suggesting/providing links, and - given the nature of the internet and individual projects - links can change and software be discontinued at any time).

Thanks a lot for your explanation.

[email protected] Do you have any idea how to create Fe2O3 slab in the LAMMPS?

Hi
Unfortunately no.