Hi Geng,
Add a &CELL_REF section
(https://manual.cp2k.org/cp2k-8_2-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS/CELL/CELL_REF.html).
With
&CELL_REF
ABC 10.83*1.5 10.83*1.5 7.22*1.5
&END
the optimization converges within 35 steps. You could decrease EPS_SCF to reduce the noise in the forces.
Cheers,
Fabian
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Hi Geng,
The plane wave basis depends on the size of the unit cell. Therefore, a change of the cell dimensions corresponds to a change of basis. If the energy difference that comes from this change of basis is large the optimizer cannot converge. With CELL_REF you prevent this issue by fixing the basis (which is now independent of the volume of the simulation domain).
By the way, you are confusing the cell optimization and SCF: The SCF is the energy minimization at each step of the cell optimization (and this always converged). Only the cell optimization did not converge.
Regarding the EPS_SCF: a tighter value can lower the number of
cell optimization steps, but each step will be more expensive. You
have to test it yourself.
Cheers,
Fabian
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