[Pw_forum] Convergence

[Stefano Baroni]

Dear Suza:

I am not sure I understand clearly your question, but it seems to me  
that an isolated infinite and charged layer cannot have any well  
defined work function, because it would generate a uniform electric  
field in the vacuum, with a corresponding potential energy that  
diverges linearly far from the layer. The lack of convergence of any  
quantities related to the electrostatic potential energy in the  
vacuum (such as the work function) is exactly what I would expect.  
Let alone the extra complications arising from periodic boundary  
conditions ...

Cheers - Stefano Baroni


On Sep 7, 2007, at 6:50 PM, Suza W wrote:

>
>
>  Dear all,
>
>  I'm running the scf calculation for a single charged
>  layer. I find that the chemical potential  is very sensitive
>  with the vacuum length. It does not  get
>  converged even after using a large vacuum of  100 a. u.
>  What should one do to get a converged value?
>
>  Yours sincerely,
>   Suza
>   Raman Research Institute
>
>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum

---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

Please, if possible, don't  send me MS Word or PowerPoint attachments
Why? See:  http://www.gnu.org/philosophy/no-word-attachments.html



-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.democritos.it/pipermail/pw_forum/attachments/20070907/b9b192d8/attachment.htm