[lammps-users] Applicability of AGNI

Hi,
I am a beginner at using LAMMPS. Can AGNI potential be used to get forces for any single atom system or is it applicable for “Al” systems only?

-Regards,
Rik

you don’t need any (non-bonded) potential for an isolated atom, since it has no other atom that it is interacting with.

axel

AGNI can only be applied to single atom type systems.

for determining how transferable the existing potential files to different systems are, you need to look up and study the publications describing the parameterizations in the associated publications.

axel.

to use AGNI on other elements, you need potential files for those elements (and environments). in general, the transferability of potentials depends strongly on how they are derived and parameterized.
again, you need to resort to studying the associated published literature for details and what has been done but is not yet included in LAMMPS. for example, there is a pending pull request with additional AGNI potential files and modifications to the pair style source code to accommodate them: https://github.com/lammps/lammps/pull/2479

axel.

since you are a beginner, I strongly recommend you start practicing with something simpler and for which more examples and precedents exist.
for metals, for example, a good starting point are embedded atom (EAM) style potentials. there are tutorials, many parameterizations and many studies with published data that you can try to reproduce and thus can learn from.

axel.

I understand. Another thing is, the potentials are built based on Al systems alone. So can it be applied to predict forces in other heavier atom systems?

What I meant was if it is applicable to single atomic “type” systems. So there will be several atoms of same type arranged in some configuration and interacting with each other.

I was also thinking of starting to learn from a simpler problem. Thank you once again for your advice.

Cheers,
Aishwaryo.