Alloy potential parameters

Hey,
Tell me how to find the parameters of potential pairs Fe - Co, Fe - Cr? If I understand correctly, are they found with the help of Lorentz-Berthelot?

Lorentz-Berthelot applies to Lennard-Jones potentials, but Lennard-Jones is not a good way to describe metals or alloys. EAM is usually better. There are plenty of ways to set these up. You may want to start searching the materials potentials database at NIST.
I also strongly recommend checking the published literature for studies of the materials that you are interested in under the conditions that you are looking to simulate. Since there are so many choices, you want to not just find something, but use a potential that is well suited for your system and conditions.

Can you please tell me if there is a database (site) for this literature?
for example site- potentials
Further,
FE - potentials FE
further, I find Fe-Fe φ (r): pFeFe.spt
I open it - FeFe.spt

is this the already found potential of Fe-Fe?

for example the standard example in LAMMPS -in.obstacle
you need to calculate the potential of the FE-FE

2d LJ obstacle flow

dimension 2
boundary p s p

atom_style atomic
neighbor 0.3 bin
neigh_modify delay 5

	# create geometry

lattice hex 0.7
region box block 0 40 0 10 -0.25 0.25
create_box 49 box
create_atoms 1 box

	# LJ potentials

pair_style lj/cut 1.12246

pair_coeff 2 2 1.0 1.0 1.12246

	# since you need to find fe - fe (the same element), then pair_coeff "**2 2 2.0 1.0 1.12**" 
	
	#**here 49 mass specifically for fe-fe** 

**mass specific value under FE-FE **
**mass specific value under FE-FE **
**mass specific value under FE-FE **

49 mass

define groups

region 1 block INF INF INF 1.25 INF INF
group lower region 1
region 2 block INF INF 8.75 INF INF INF
group upper region 2
group boundary union lower upper
group flow subtract all boundary

set group lower type 2
set group upper type 3

initial velocities

compute mobile flow temp
velocity flow create 1.0 482748 temp mobile
fix 1 all nve
fix 2 flow temp/rescale 200 1.0 1.0 0.02 1.0
fix_modify 2 temp mobile

Poiselle flow

velocity boundary set 0.0 0.0 0.0
fix 3 lower setforce 0.0 0.0 0.0
fix 4 upper setforce 0.0 NULL 0.0
fix 5 upper aveforce 0.0 -0.5 0.0
fix 6 flow addforce 1.0 0.0 0.0

2 obstacles

region void1 sphere 10 4 0 3
delete_atoms region void1
region void2 sphere 20 7 0 3
delete_atoms region void2

fix 7 flow indent 100 sphere 10 4 0 4
fix 8 flow indent 100 sphere 20 7 0 4
fix 9 all enforce2d

Run

timestep 0.003
thermo 1000
thermo_modify temp mobile

dump 1 all atom 100 dump.obstacle

#dump 2 all image 500 image.*.jpg type type &

zoom 1.6 adiam 1.5

#dump_modify 2 pad 5

#dump 3 all movie 500 movie.mpg type type &

zoom 1.6 adiam 1.5

#dump_modify 3 pad 5

run 25000

do I understand the logic correctly?

Sorry, I do not understand much of what you are trying to explain and ask and thus have to guess.
It may help to ask somebody with more practice in writing in English to help you reformulate your posts, in case my response is not answering your questions.

If you need more information about that website, you need to ask the people operating it.
If you need more information about the individual potentials, you need to follow the instructions given and look up and study the corresponding publications and/or contact the corresponding authors.

At any rate the LAMMPS documentation explains in great detail how to use and read potential files for all supported pair styles and what the specific files have to look like that LAMMPS can handle. The rest is really up to you.

This example uses a repulsive only Lennard-Jones interaction. There is no mention anywhere about Fe-Fe interactions.

understood thanks.

Hello. can tell me where to find the parameters of interaction fe-fe?
and describe in LAMMPS

There are loads of publications discussing parameters for Fe-Fe. You not only need something that matches the elements, but also can represent the desired thermodynamic state well. There are also databases. Please see the LAMMPS manual.
Once you have the suitable parameters/publication, you can look into which pair style would be required to use them.