[Pw_forum] Another SCF convergence problem

[Stefano Baroni]

On Oct 3, 2007, at 8:07 PM, Axel Kohlmeyer wrote:

> On Wed, 3 Oct 2007, Vidur Parkash wrote:
>
> dear vidur,
>
> VP> Sorry bout that....yes I meant K_POINTS, is there any thumb  
> rule for
> VP> deciding how many K-points are good for convergence. Is it  
> dependent
> VP> on the nature of the system, or on the number of atoms or  
> something
> VP> else
>
> how about picking up a text book about condensed matter electron
> structure calculations and answering that question yourself?
> look for BZ-sampling...
>
> you might find the answers to some other (future) problems, too. :)

Vidur: as an "old-style" professor, I tend to sympathize with Axel's  
viewpoint (who, by the way, is much younger than me!). If you choose  
to trust Axel's advice, a very good starting point is Richard  
Martin's textbook on electronic structure. Richard has been kind  
enough (and smart enough with the publishing company) to make a few  
selected chapters of his textbook available on the net. Vidur: you  
are very lucky! What you need can be downloaded for free from here:

http://electronicstructure.org/Selected_Chapters/Martin-ch04.pdf

Of course, the free download wil not save you from a few afternoons  
of hard study. If you like it, please do not refrain from downloading  
(and studying!) the other chapters too.

Good luck! Stefano

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

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