[Pw_forum] NEB first_last_opt

[Giuseppe Mattioli]

Sorry, the only one *who* can think through it...:-)
G.

Quoting Aleksandra Oranskaia <aleksandra.oranskaia at kaust.edu.sa>:

> Hello dear QE users,
>
> I have a question regarding pre-optimization of starting and ending  
> points of NEB.
>
> Dealing with multi-scale simulation of a vacancy migration in a huge  
> supercell (say, 350-400 atoms), should one make a pre-optimization  
> of starting and ending points of a path?
>
> I tried both ways and came to the conclusion that pre-optimization  
> pushes the system away from the minimum energy path (leading to the  
> increased barriers), because pre-optimization implies too deep  
> restructuring towards deeper minimums rather than the local minimums  
> closest to the minimum energy pathway.
> In my opinion it is more physical if a migration corresponds to a  
> minimum energy pathway AND minimum restructuring.
>
> If you would simulate vacancy migration in a huge supercell with NEB  
> optimization, would you optimize starting and ending points? Why?
>
>
> Thanks in advance and hope to hear your opinions and reasonings,
>
> Regards,
> Alex.
> --
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    Giuseppe Mattioli
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