[Pw_forum] "relax" vs. "vc-relax" calculation

[Tram Bui]

Dear Masoud,

 Thank you for your information. The tutorial is also very helpful. I have
some small questions related to the tutorial, I hope you don't mind. on the
slide # 11, the author has used the "Ω" sign, and what does it represent?.
also on the slide # 32, there is a warning sign saying "the total number of
electron is odd", so the degauss value was marked very low, as 0.0037. So
does it mean that the degauss should be low for odd number of electron and
higher for even cases?

I really appreciate your helps!
Tram


On Thu, Jul 7, 2011 at 2:32 AM, Masoud Nahali <masoudnahali at gmail.com>wrote:

>
>      Dear Tram
>
>          I think that vc-relax calculation is more convenient for your
> case; in addition you should glance over the below tutorial about defects :
>
> http://www.fisica.uniud.it/~giannozz/QE-Tutorial/tutorial_defects.pdf
>
>          I hope it is useful.
>
>
> Best Wishes
>
>  Masoud
>
>
>
> --------------
> Masoud Nahali, Sharif University of Technology
> masoud.nahali at gmail.com; alum.sharif.edu/~m_nahali<http://alum.sharif.edu/%7Em_nahali>
>
> P Please don't print this e-mail unless you really need to.
>
>
> *Tram wrote on Thu Jul 7 06:47:35 CEST 2011*
>>
> Dear Everyone,
>      I have a quick question regarding the "relax" vs. "vc-relax"
> calculation for my SiC structure. As I run the " scf" calculation with a
> single defect, e.g. interstitial or sustitutional, the lattice parameter of
> the unit cell is expected to be stretched. And as I checked, the lattice
> constant got larger when introduced defect. Now, I'm just wondering between
> the "relax" calculation (which will only relax the atomic position ) and the
> "vc-relax" one (which will relax both atomic position and the lattice of the
> unit cell), which one would you recommend to use?
>
> Thank you very much,
>
> Tram Bui
>
> M.S. Materials Science & Engineering
> trambui at u.boisestate.edu <http://www.democritos.it/mailman/listinfo/pw_forum>
>
>
>
>
>
>
>
>
>
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>


-- 
Tram Bui

M.S. Materials Science & Engineering
trambui at u.boisestate.edu
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