Hi Giuseppe, The PPs part in my input is:
ATOMIC_SPECIES Al 26.98 Al.pbe-tm-gipaw-dc.UPF O 16.00 O.pbe-tm-new-gipaw-dc.UPF P 30.97 P.pbe-tm-new-gipaw-dc.UPF I got these PP files from here: https://sites.google.com/site/dceresoli/pseudopotentials I always use them for GIPAW calculations and they works fine. Never realized they might not be suitable for other types of calculations like optimization. So I think this is a good chance for me to get educated. lol Thanks again! Best, James -----Original Message----- From: pw_forum-bounces at pwscf.org [mailto:[email protected]] On Behalf Of Giuseppe Mattioli Sent: Tuesday, January 28, 2014 2:15 PM To: pw_forum at pwscf.org Subject: Re: [Pw_forum] optimization and pseudo potentials Dear James Hard to help you without seeing the PP files or their generation input files. Where did you find the PPs? I do not spot them in the online library... Yours Giuseppe Giuseppe Mattioli ISM-CNR Italy Quoting James Mao <xjamesmao at gmail.com>: > Dear users, > > > > I am trying to calculate NMR chemical shifts by GIPAW for a crystal > (with atoms Al, P, O). The pps I used > > with GIPAW are "pbe-tm-gipaw-dc" sets. I did get reasonable results. > > > > For a second step I tried to optimize the structure. I noticed if I > still used the gipaw pps, the optimization > > process is completely wrong. In vc-relax calculations the cell volume > keeps shrinking to 67% of original > > volume (which is from experimental structure). While I changed the pps > to "pbe-n-kjpaw" set, vc-relax > > gave reasonable results. > > > > I would be very thankful if someone can explain a little bit for me > what kind of pps are not suitable for > > optimization so in future I can avoid similar mistake? Any helps will > be greatly appreciated. > > > > Best regards, > > James Mao > > > > Postdoc associate > > Department of Chemistry, > > University of Pittsburgh -- ******************************************************** - 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> _______________________________________________ Pw_forum mailing list Pw_forum at pwscf.org http://pwscf.org/mailman/listinfo/pw_forum
