[Pw_forum] Fw: defect formation energy

[Duy Le]

if the defect concentration is too hight, when you do vc-relax the lattice
parameter will be re-optimized. In reality, the defect concentration is
about zero.

On Fri, Sep 18, 2009 at 8:43 AM, xirainbow <nkxirainbow at gmail.com> wrote:

> Dear:
>
> When you calculate without vc-relax, you deal with a point defect.
> When you use vc-relax, you change the crystal parameters. That is to say,
> you deal with a new kind of crystal, not a point defect.
> It is just my own point of view ：）
>
>
>
>>
>> Ali Kazempour
>> Physics department, Isfahan University of Technology
>> 84156 Isfahan, Iran. Tel-1: +98 311 391 3733
>> Fax: +98 311 391 2376 Tel-2: +98 311 391 2375
>>
>> --- On *Fri, 9/18/09, ali kazempour <kazempoor2000 at yahoo.com>* wrote:
>>
>>
>> From: ali kazempour <kazempoor2000 at yahoo.com>
>> Subject: defect formation energy
>> To: forum at democritos.it
>> Date: Friday, September 18, 2009, 5:31 AM
>>
>>
>> Hi
>> for study of point defect ,  i do relax calculation and obtain positive
>> defect formation energy while by vc-relax i gain negative. ?
>> what is the difference between positive and negative formation energy?
>> waht is the physical reasons?
>> thanks a lot
>> Ali Kazempour
>> Physics department, Isfahan University of Technology
>> 84156 Isfahan, Iran. Tel-1: +98 311 391 3733
>> Fax: +98 311 391 2376 Tel-2: +98 311 391 2375
>>
>>
>
>
> --
> ____________________________________
> Hui Wang
> School of physics, Nankai University, Tianjin, China
>
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-- 
--------------------------------------------------
Duy Le
PhD Student
Department of Physics
University of Central Florida.
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