Proper use of BNCH.ILP potential?

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1

Hi Nicolas,
It seems you didn’t assign a unique molecule id for each layer of graphene, as a result, the interlayer interaction is not calculated.

In the document (https://lammps.sandia.gov/doc/pair_ilp_graphene_hbn.html), there is Note:

Note

This potential is intended for interactions between two different layers of graphene or hexagonal boron nitride. Therefore, to avoid interaction within the same layers, each layer should have a separate molecule id and is recommended to use “full” atom style in the data file.

You can find examples from the directory ${LAMMPS_package}/examples/USER/misc/ilp_graphene_hbn.

Please let me know if you have further questions.

Best,
Wengen

2

Dear Wengen,

Thank you for your answer.

I managed to set up the system now, defining the molecule ID. I ended up using the read_data command rather than the create_atoms with the basis flag as I did before.

It runs properly now, however I’ve just noticed that the minimization hangs when I don’t fix one of the layers using

fix subf adsorbate setforce 0.0 0.0 0.0

It simply gets stuck after a fixed number of timesteps (this value is different depending on the minimization scheme I use, but all that I tried ended up hanging).
There is no error message popping up, even when running it interactively.

But if I use this fix setforce command (as in the example file), it relaxes properly.

I’ll try few more things so that I can also simulate a free-standing system rather than only this one here with fixed substrate, but feel free to comment if you know what is going on.

Regards,
Nicolas

3

Hi Nicolas,
For the stuck problem, I received several similar reports from different researchers, actually I’m working on it recently.
I think I already find the reason, but just to be sure, can you send your input file (including log file) for me so I can do a test?
After I confirm this issue, I will update the modified codes to LAMMPS soon.
Thanks!

Best,
Wengen