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 & Universit? Paris 6 > phone:+33 (0)1 44275 084 / skype: paulatz > www: http://www-int.impmc.upmc.fr/~paulatto/ > mail: 23-24/4?16 Bo?te courrier 115, 4 place Jussieu 75252 Paris C?dex 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://pwscf.org/pipermail/pw_forum/attachments/20140116/913d0b9c/attachment.html
