[Pw_forum] volume optimization

[mohnish pandey]

On Fri, Feb 3, 2012 at 2:59 AM, berber mo <berbermohamed at yahoo.fr> wrote:

> I work on wien2k 8 and i have problem with volume optimization .
> I would like to know in detail how to optimize the volume
> a =15.95 u.a               b = 19.53 u.a                            c =15.95
> u.a
> alpha=90 °                  beta =90 °                                  gamma
> =144.73 °
>

The information you provided is very less. As far as I can understand this
is the input that you want to give and then see the optimized structure
with optimized volume and atomic coordinates. since your alpha and beta are
equal as well  "a" and "c" so I will suggest you to reorient (rotate the
unit cell around x-axis by Pi/2 ) the cell such that your "b"  becomes "c"
and "gamma" will become "alpha." So in the new unit cell you will have
(just check it carefully, I may be slightly wrong)
a =15.95 A°               b =15.95 A°                              c =19.53
A°
 alpha=144.73 °          beta =90 °                                  gamma =90
°
With this cell you can use the option ibrav = 5 ( celldm4 = cos(alpha) ).

And next time you post on this forum please sign in your affiliation.

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-- 
Regards,
MOHNISH,
-----------------------------------------------------------------
Mohnish Pandey
BTech-Mtech, IIT Kanpur
Senior Project Associate,
Department of Chemical Engineering,
IIT KANPUR, UP, INDIA
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