OK thanks Paolo that's clear now. Cyrille ======================== Cyrille Barreteau CEA Saclay, IRAMIS, SPEC Bat. 771 91191 Gif sur Yvette Cedex, FRANCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +33 1 69 08 38 56 /+33 6 47 53 66 52 (mobile) email: [email protected] Web: http://iramis.cea.fr/Pisp/cyrille.barreteau/ ======================== ________________________________ De : [email protected] [[email protected]] de la part de Paolo Giannozzi [[email protected]] Envoyé : jeudi 27 juillet 2017 13:17 À : PWSCF Forum Objet : Re: [Pw_forum] vc-relax & cell_dofree
It is easier to figure out what the various "cell_dofree" options do from the code than from the documentation: look for routine 'init_dofree" in Modules/cell_base.f90 (iforceh(i,j)=0 means "keep component i of basis vector j fixed") Paolo On Tue, Jul 25, 2017 at 12:19 PM, BARRETEAU Cyrille <[email protected]<mailto:[email protected]>> wrote: Thanks for your reply but I am still not very sure I understand well the difference between the two options: 'xy' : only v1_x and v2_y are moved '2Dxy' : only x and y components are allowed to change When the vectors v1 and v2 are not orthogonal (which is my case) the option 'xy' is not appropriate ? Cyrille ======================== Cyrille Barreteau CEA Saclay, IRAMIS, SPEC Bat. 771 91191 Gif sur Yvette Cedex, FRANCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +33 1 69 08 38 56<tel:+33%201%2069%2008%2038%2056> /+33 6 47 53 66 52 (mobile) email: [email protected]<mailto:[email protected]> Web: http://iramis.cea.fr/Pisp/cyrille.barreteau/ ======================== ________________________________ De : [email protected]<mailto:[email protected]> [[email protected]<mailto:[email protected]>] de la part de Thomas Brumme [[email protected]<mailto:[email protected]>] Envoyé : mardi 25 juillet 2017 11:32 À : [email protected]<mailto:[email protected]> Objet : Re: [Pw_forum] vc-relax & cell_dofree Dear Cyrille, from the input description: 'xy' : only v1_x and v2_y are moved '2Dxy' : only x and y components are allowed to change Thus, even in the case of cell_dofree='xy' I think the cell will change. Anyway, the deviation from 120 DEG is quite small (119.43 DEG if I'm not wrong) - I don't know if this could be do to numerical issues. Maybe try starting a new relaxation with a hexagonal cell but smaller in-plane lattice vector of ~99.1% Cheerio Thomas On 07/25/17 09:08, BARRETEAU Cyrille wrote: Dear QE community I have a question related to vc-relax and the option cell_dofree. I want to relax a 2D metal-organic framework (MOF) with hexagonal lattice (ibrav=4) Could you please explain what is the difference between cell-dofree=xy and cell_dofree=2Dxy? I have noticed that when using cell_dofree=2Dxy the final CELL_PARAMETER is no longer perfectly hexagonal (see below). Should I use cell_dofree=xy instead and why? final: CELL_PARAMETERS (alat= 25.44640422) 0.990921488 -0.000187347 0.000000000 -0.495622997 0.858299558 0.000000000 0.000000000 0.000000000 0.742630080 Thanks in advance Cyrille ======================== Cyrille Barreteau CEA Saclay, IRAMIS, SPEC Bat. 771 91191 Gif sur Yvette Cedex, FRANCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +33 1 69 08 38 56 /+33 6 47 53 66 52 (mobile) email: [email protected]<mailto:[email protected]> Web: http://iramis.cea.fr/Pisp/cyrille.barreteau/ ======================== ________________________________ _______________________________________________ Pw_forum mailing list [email protected]<mailto:[email protected]> http://pwscf.org/mailman/listinfo/pw_forum -- Dr. rer. nat. Thomas Brumme Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry Leipzig University Phillipp-Rosenthal-Strasse 31 04103 Leipzig Tel: +49 (0)341 97 36456<tel:+49%20341%209736456> email: [email protected]<mailto:[email protected]> _______________________________________________ Pw_forum mailing list [email protected]<mailto:[email protected]> http://pwscf.org/mailman/listinfo/pw_forum -- Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
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