[CP2K-user] [CP2K:14431] Cell_OPT convergence is too slow

[rui zou]

Hi, Matthias Krack

Thank you so much for your advice. 
In this calculation I used a supercell of 320 atoms. I suspect this also 
caused the convergence rate to be too slow. When performing CELL_OPT in 
CP2K, is it necessary to expand the cell first? 

Best regards
Rui Zou

在2020年12月25日星期五 UTC+8 下午7:02:58<Matthias Krack> 写道：

> Hi Rui Zou
>
>  
>
> There are two issues which might hamper the convergence process of your 
> cell_opt run:
>
>    1. The SCF convergence threshold value is with 5.0E-6 quite large 
>    which will cause a low accuracy of the calculated forces. Noisy forces will 
>    in turn “confuse” the optimizer.
>    2. The applied constraints KEEP_ANGLES and KEEP_SYMMETRY might prevent 
>    the optimiser from finding an energetically lower lying structure with less 
>    symmetry indicated by residual forces.
>
>  
>
> HTH
>
>  
>
> Matthias
>
>  
>
> *Von:* c... at googlegroups.com <c... at googlegroups.com> *Im Auftrag von *rui 
> zou
> *Gesendet:* Freitag, 25. Dezember 2020 05:41
> *An:* cp2k <c... at googlegroups.com>
> *Betreff:* [CP2K:14431] Cell_OPT convergence is too slow
>
>  
>
> Hi everyone!
>
>  
>
> I am a new user of CP2K. I want to use CP2K to optimize the cell. However, 
> the convergence of this process is too slow. Can you help me check if there 
> is a problem with my input file? Thank  you so much!
>
>  
>
> Best regards,
>
> Rui Zou
>
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