[Pw_forum] problem in determine cell_factor

[ehsan targholi]

thanks a lot for your reply
You say is absolutely correct. I use of "cell_dofree= '2Dxy'" to vc-relax
act in tow dimension .
I have another problem for obtain the cell parameter in my output file ;
because espresso  report cell parameter in alat unit & I could not convert
alart unit to angstrom.


CELL_PARAMETERS (alat= 4.66006464)

1.000088817 -0.000079162 0.000000000

0.499975852 0.866141905 0.000000000

0.000000000 0.000000000 6.082725061





best regard

ehsan targholi


On Wed, Jan 15, 2014 at 10:02 PM, Lorenzo Paulatto <
lorenzo.paulatto at impmc.upmc.fr> wrote:

> On 01/15/2014 05:27 PM, ehsan targholi wrote:
> > how i can determine the best value of cell_factor parameter for my cell?
>
> Just put it large enough, i.e. 3. But be aware that if the volume
> changes so much, the initial guess may have been quite bad,.
>
> > my cell is graphene sheet with 55  atom of carbon
>
>
> Are you sure that doing a variable cell relax calculation of a 2D
> supercell is a good idea? You should at the very least block the
> relaxing of the out-of-plane axis.
>
> best regards
>
> --
> Dr. Lorenzo Paulatto
> IdR @ IMPMC -- CNRS & Université Paris 6
> phone:+33 (0)1 44275 084 / skype: paulatz
> www:  http://www-int.impmc.upmc.fr/~paulatto/
> mail: 23-24/4é16 Boîte courrier 115, 4 place Jussieu 75252 Paris Cédex 5
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20140116/913d0b9c/attachment.html>