Thanks a lot, Dr. Mattioli. If this is the case, then I would just go ahead with a fixed cell relax calculation.
Thanks Mitul On Thu, Feb 6, 2014 at 2:08 PM, Giuseppe Mattioli < giuseppe.mattioli at ism.cnr.it> wrote: > > Dear Mitul > If I remember well you cannot perform NEB calculations in a variable-cell > framework. You should choose a reasonable set of lattice parameters along > the whole reaction path. > HTH > Giuseppe > > On Thursday 06 February 2014 07:36:18 Mitul Mundra wrote: > > Hello, > > > > I need to do NEB calculations for my system. My system consists of Si > 2*2*2 > > supercell with some Li impurities. Prior to NEB, I am doing a vc-relax > > calculation to get the minimum energy states for the first and the last > > images of the NEB. For the vc-relax, I set *ibrav = 1* for the symmetric > > cubic system. In the results obtained from vc-relax calculation, the > cubic > > symmetry of the system is lost and I get the following call parameters > for > > the initial and final state in the output file. > > > > CELL_PARAMETERS (alat= 20.51108588) > > 1.011059885 -0.002882944 -0.000008465 > > -0.002882944 1.011059885 0.000008465 > > -0.000008492 0.000008492 1.007297719 > > > > CELL_PARAMETERS (alat= 20.51108588) > > 1.004932042 0.000000442 -0.000000442 > > 0.000000442 1.004688370 0.000104290 > > -0.000000442 0.000104290 1.004688370 > > > > Now, I am confused about my input file for the NEB. I can not just > directly > > change the lattice constant by taking the cube root of the new volume > > obtained. I tried to set* ibrav = 0* and give the cell parameters > obtained > > but I can only enter them once (correct me if I am wrong) and thus, can > not > > incorporate both the set of cell parameters. I would be extremely > thankful > > if anyone could suggest me a way to tackle this difficulty. > > > > > > Thanks > > Mitul Mundra > > Final year Dual Degree Student > > Department of Chemical Engineering > > IIT Kanpur > > > ******************************************************** > - Article premier - Les hommes naissent et demeurent > libres et ?gaux en droits. Les distinctions sociales > ne peuvent ?tre fond?es que sur l'utilit? commune > - Article 2 - Le but de toute association politique > est la conservation des droits naturels et > imprescriptibles de l'homme. Ces droits sont la libert?, > la propri?t?, la s?ret? et la r?sistance ? l'oppression. > ******************************************************** > > Giuseppe Mattioli > CNR - ISTITUTO DI STRUTTURA DELLA MATERIA > v. Salaria Km 29,300 - C.P. 10 > I 00015 - Monterotondo Stazione (RM) > Tel + 39 06 90672836 - Fax +39 06 90672316 > E-mail: <giuseppe.mattioli at ism.cnr.it> > ResearcherID: F-6308-2012 > > _______________________________________________ > 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/20140206/3da31b0c/attachment.html
