[Pw_forum] Regarding symmetry

[Paolo Giannozzi]

On Sat, 2013-05-11 at 11:34 +0430, mohaddeseh abbasnejad wrote:

> I provided my structure with the space group P-62m , recognizing 12
> symmetry. However, the symmetry changed to 4 during the variable cell
> relaxation.

this should not happen: the structural optimization conserves
the symmetry, unless there is some numerical noise, or unless
there is some symmetry-breaking constraint (e.g. fix the position
of some atoms)

> One more question: I tried to use the "press_conv_thr" keyword during
> the variable cell relaxation to keep the pressure on my structure in
> 160 GPa. However, it did not apply. 

what do you mean by "it did not apply"? the target pressure is not set
by that variable.

P.

-- 
Paolo Giannozzi, Dept. Chemistry&Physics&Environment, 
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222