Dear All I am calculating the band structure of phagraphyne. First we computed for primitive unit cell and then for the 2X2 supercell. Although the bulk structure is same the band structure is different. What is the problem ? Should parameters be optimized again for supercell?
Mohammadreza Hosseini Tarbiat modares uiversity ________________________________________ From: [email protected] <[email protected]> on behalf of [email protected] <[email protected]> Sent: Saturday, May 13, 2017 10:00 PM To: [email protected] Subject: Pw_forum Digest, Vol 118, Issue 12 Send Pw_forum mailing list submissions to [email protected] To subscribe or unsubscribe via the World Wide Web, visit http://pwscf.org/mailman/listinfo/pw_forum or, via email, send a message with subject or body 'help' to [email protected] You can reach the person managing the list at [email protected] When replying, please edit your Subject line so it is more specific than "Re: Contents of Pw_forum digest..." Today's Topics: 1. Re: how to determine the symmetry of a given phonon mode in quantum espresso (Lorenzo Paulatto) 2. Re: Gipaw - Magnetic susceptibility (Davide Ceresoli) ---------------------------------------------------------------------- Message: 1 Date: Sat, 13 May 2017 15:08:04 +0200 From: Lorenzo Paulatto <[email protected]> Subject: Re: [Pw_forum] how to determine the symmetry of a given phonon mode in quantum espresso To: PWSCF Forum <[email protected]> Message-ID: <1728518.gkaUiGcZ5e@paulaxps> Content-Type: text/plain; charset="iso-8859-1" On Friday, 12 May 2017 23:44:33 CEST Mihiri Hewa bosthanthirige wrote: > Hi, > I am graduate student at Clemson university, currently working with Quantum > Espresso. I would like to know how to determine the symmetry of a given > phonon mode in quantum espresso. Hello, it is printed in the output of phonon at the end of the calculation, i.e.: ... End of self-consistent calculation -- Dr. Lorenzo Paulatto IdR @ IMPMC -- CNRS & Universit? Paris 6 +33 (0)1 44 275 084 / skype: paulatz http://www.impmc.upmc.fr/~paulatto/ 23-24/4?16 Bo?te courrier 115, 4 place Jussieu 75252 Paris C?dex 05 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20170513/0ddc04ba/attachment-0001.html ------------------------------ Message: 2 Date: Sat, 13 May 2017 16:09:02 +0200 From: Davide Ceresoli <[email protected]> Subject: Re: [Pw_forum] Gipaw - Magnetic susceptibility To: PWSCF Forum <[email protected]> Message-ID: <[email protected]> Content-Type: text/plain; charset=windows-1252; format=flowed Dear Alan, I think that there is no problem in doing a G=0 response with a shifted mesh. The response is at G=0, hence it couples wfcs at the same k. The susceptibility depends a lot on k-points sampling and if your system has a vanishing band gap, convergence can be a nightmare. By default the macroscopic shape is diagonal: nmr_macroscopic_shape(:,:) = 0.d0 nmr_macroscopic_shape(1,1) = 2.d0 / 3.d0 nmr_macroscopic_shape(2,2) = 2.d0 / 3.d0 nmr_macroscopic_shape(3,3) = 2.d0 / 3.d0 You can change the component (demagnetizing field) in the input file. Good luck for your calculations! Best, Davide On 05/12/2017 07:47 PM, Ambrozio wrote: > Dear QE users and Developers, > > I'm working with NMR calculations in Gipaw. Recently I did some shielding > calculations and I have some questions regarding the magnetic susceptibility. > The article from developers Mauri et al (*PRL 77, 26, 1996*) explain that the > shielding of a bulk of a periodic system is also periodic (i.e. has the same > periodicity of *G*, the reciprocal lattice vectors), and it is proportional to > the magnetic susceptibility matrix. In the paper Mauri did a short discussion > about the macroscopic susceptibility, which is calculated at *G=0*. Follow my > questions: > > i) Assuming that the macroscopic susceptibility is calculating at gamma point > (*G=0*) and depends of the sample's shape, Does make sense to do a NMR > calculation with automatic kpoints (monkhorst pack grid) that does not > include > the gamma point? It is mandatory to including the gamma point when the shape > correction is .true.? > > ii) Does the susceptibility depends of the supercell size? I found very > different susceptibilities for the same material (AB graphite) changing the > supercell size. > > iii) Why the susceptibility matrix is not diagonal when the shape correction > is > .true.? Assuming the Mauri paper I think it doens't make sense. Help me to > understand... > > > I appreciate any help, > > Thanks in advance, > > > Alan. > > > > -- > > Alan J. Romanel Ambrozio > Bacharel em F?sica > Mestre em Eng. de Materiais > Doutorando em F?sica - PPGFis > > > -- +--------------------------------------------------------------+ Davide Ceresoli CNR Institute of Molecular Science and Technology (CNR-ISTM) c/o University of Milan, via Golgi 19, 20133 Milan, Italy Email: [email protected] Phone: +39-02-50314276, +39-347-1001570 (mobile) Skype: dceresoli Website: http://sites.google.com/site/dceresoli/ +--------------------------------------------------------------+ ------------------------------ _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum End of Pw_forum Digest, Vol 118, Issue 12 ***************************************** _______________________________________________ Pw_forum mailing list [email protected] http://pwscf.org/mailman/listinfo/pw_forum
