Minimization change the energy trend of bending graphene with different curvature

LAMMPS LAMMPS General Discussion
1

Hello LAMMPS users, I encountered a problem when minimizing a series of graphene with different curvatures. Specifically, the initial energy of the bending graphene increases gradually as the curvature increasing, which is reasonable in physic. However, after minimization, the above mentioned law lost, and there is no evident law between energy and curvature. But the minimized sample does not show evident structure change. To obtain a physical reasonable result, I have adjusted the minimization method and convergence criterion, but it does not work. When I adopt an airebo potential the law keeping after minimization. It seems that the previously used reactive force field is incorrect, however it was widely adopted. I don’t know the error is caused by the force field or the wrong settings in the lammps script. The used initial configurations of bending graphene, force field file, lammps input script and result are upload as attachments. Please give me some advices, I am really looking forward to all your reply.

results-relationship between energy and curvature.tif (7.8 MB)

SiLiOCHF.Reaxff (11.8 KB)

lammps.in (596 Bytes)

initial configurations of bending graphene with different curvatures.rar (574.0 KB)

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I tried a random case of your input (r=48). I would say that the structural change during minimization is quite noticeable (by naked eyes), and the energy change during minimization is not small. So I think your observation on the energy curve is not too surprising. Whether it’s physically correct or not is another problem though; I don’t know much about this system so I can’t tell.

Anyway, if you get different results from another force field, then the problem likely lies in there. You said “It seems that the previously used reactive force field is incorrect, however it was widely adopted.”. Did you mean that this force field is widely adopted for studying graphene (and its deformation)?

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Thanks for your advice. I will do some further evaluation work.