Convergence Problem

[weiyidan]

Hi Professor,

I am working on a ferromagnetic system. Although it can converge to Ediff=-0.05, it can not converge to Ediffg=-0.01. I have tired several methods including changing its height of molecular, fixing some atoms, improving EDIFF criterion from 1E-5 to 1E-7 and decreasing POTIM from 0.3 to 0.1. Forces on molecular are still large and vibrate at around 0.08. However, none of them works. Can you give me some suggestions and help me out of dilemma？ Thanks for your suggestion and time.

Best Regards,

Dan

[graeme]

The energy and forces are dropping steadily so you should be able to keep running. The slow convergence may be related to the fact that you have no frozen atoms, so there could be soft modes. But anyway, I don't see any problems with the convergence rate in this calculation.

[weiyidan]

Thanks very much, professor. You help me so much as before.

[weiyidan]

Can you tell me how to accelerate my calculation? Which part of atoms should be fixed? And What is soft modes?