[Wien] Formula to calculate Lattice Constant and angle of BiFeO3

[Mian Fayyaz Ahmad]

Respected,  "delamora at unam.mx"
        Still i am confusing how to calculate . As you mentioned but still
confusion about concrete steps as you mentioned
( First you optimize a, b, c
then you vary alpha and optimize, then beta and finally gamma

then you return to the beginning;

optimize a, b and c

until the changes in the cell parameters change little.).

 According to user guide at page #66 (listed from 1-6 ) in volume
optimization case.

Please guide me according to list in user guide step wise.

I would be very thankful to you.


On Tue, Jun 24, 2014 at 12:30 AM, delamora <delamora at unam.mx> wrote:

>  Yes, in the WIEN2k you find a, b and c optimization all set for you, but
> ti include the angles the number of structures would increase exponentially;
>
> 1 dimension    n
>
> 2 dimensions    n**2
>
> 3 dimensions    n**3
>
> 4 dimensions    n**4
>
> 5 dimensions    n**5
>
> 6 dimensions    n**6
>
>
>  4**6=4096
>
>
>  So you must do each optimization separately
>
> First you optimize a, b, c
>
> then you vary alpha and optimize, then beta and finally gamma
>
>
>  then you return to the beginning;
>
> optimize a, b and c
>
> until the changes in the cell parameters change little.
>
>
>  ------------------------------
> *De:* wien-bounces at zeus.theochem.tuwien.ac.at <
> wien-bounces at zeus.theochem.tuwien.ac.at> en nombre de Mian Fayyaz Ahmad <
> fayyaz.pc at gmail.com>
> *Enviado:* domingo, 22 de junio de 2014 09:41 p.m.
> *Para:* Wien at zeus.theochem.tuwien.ac.at
> *Asunto:* [Wien] Formula to calculate Lattice Constant and angle of BiFeO3
>
>
>  *Respected, Wien2K Community*
>  *   I want to **calculate Lattice Constant and angle of BiFeO3 in space
> group P1( Triclinic ). I have done volume optimization. I found a formula
> [V = abc( 1-cos**2alpha -**cos**2beta**- **cos**2gamma**+2***cos alpha***cos
> beta***cos gamma)**1/2]. I found only volume in volume optimization. How
> can i found lattice parameters a, b , c and angles??? *
> *please help me in this regard.*
>  *thanks in advance*
>
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