Dear Elham, Relaxation only minimizes ion positions+electronic charges, and not lattice constants (a,b,c). If you initiate from experimental structures, I propose to do VC-RELAX. During vc-relax, it is possible that a,b,c,alpha,beta, and gamma to be changed. If you relax a structure, and then change its composition (for example, doped one atom inside it), it depends that what you want. For example, if you have a slab for which some layers act as bulk, you should not use vc-relax. But if you use a sheet such as graphene, you can use vc-relax but with constrain in z axis. Regards
David Foster Ph.D. Student of Chemistry -------------------------------------------- On Sun, 8/2/15, Elham <e.chemistr...@gmail.com> wrote: Subject: [Pw_forum] vc-relax calculation To: pw_forum@pwscf.org Date: Sunday, August 2, 2015, 10:16 PM Dear PWSCF experts and PWSCF users Is necessary do vc-relax calculation after the relax calculation for electronic calculation (band,dos,..)? What is necessary do vc-relax calculation? Thanks so muchElham -----Inline Attachment Follows----- _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum