Dear Vega, Please be not so official. I add (automatically) my affiliation due to our accepted Netetiquette.
Bests, Eyvaz. ------------------------------------------------------------------- Prof. Eyvaz Isaev, Theoretical Physics Department, Moscow State Institute of Steel & Alloys, Russia, Department of Physics, Chemistry, and Biology (IFM), Linkoping University, Sweden Condensed Matter Theory Group, Uppsala University, Sweden Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com --- On Thu, 8/28/08, vega <vegalew at hotmail.com> wrote: > From: vega <vegalew at hotmail.com> > Subject: Re: [Pw_forum] something strange in rutile and anatase calculation > To: eyvaz_isaev at yahoo.com, "PWSCF Forum" <pw_forum at pwscf.org> > Date: Thursday, August 28, 2008, 5:08 PM > Thank you for Prof. Eyvaz Isaev's hints > I'll read the excellent article as your suggestion. > It's really nice of you. > > vega > > -------------------------------------------------- > From: "Eyvaz Isaev" <eyvaz_isaev at yahoo.com> > Sent: Thursday, August 28, 2008 8:58 PM > To: "PWSCF Forum" <pw_forum at pwscf.org> > Subject: Re: [Pw_forum] something strange in rutile and > anatase calculation > > > Hi, > > > > One more suggestion. > > As far as I know the same situation is for \alpha > and \omega phases of Ti, > > as well as HCP and DHCP phases of FeH. But free energy > calculations have > > shown than \alpha-Ti and DHCP FeH are stabilized > due to the phonon > > contribution. > > For FeH you can see: Eyvaz I. Isaev et al., Dynamical > stability of Fe-H in > > the Earth's mantle and core regions, Proceedings > of the National Academy > > of Sciences of the USA (PNAS), 104 (22), 29 May 2007, > 9168. PNAS Special > > Issue "Geophysics". > > > > So, you can try follow this way, if you like. > > > > Bests, > > Eyvaz. > > > > > > > ------------------------------------------------------------------- > > Prof. Eyvaz Isaev, > > Theoretical Physics Department, Moscow State Institute > of Steel & Alloys, > > Russia, > > Department of Physics, Chemistry, and Biology (IFM), > Linkoping University, > > Sweden > > Condensed Matter Theory Group, Uppsala University, > Sweden > > Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, > eyvaz_isaev at yahoo.com > > > > > > --- On Thu, 8/28/08, Nicola Marzari > <marzari at MIT.EDU> wrote: > > > >> From: Nicola Marzari <marzari at MIT.EDU> > >> Subject: Re: [Pw_forum] something strange in > rutile and anatase > >> calculation > >> To: "PWSCF Forum" > <pw_forum at pwscf.org> > >> Date: Thursday, August 28, 2008, 3:01 PM > >> vega wrote: > >> > Dear all, > >> > > >> > It is known that the rutile is more stable > than > >> anatase in > >> > thermodynamics. Surprisingly, when I did the > vc-relax > >> calculation by > >> > QE, I found the calculated energy of anatase > lower > >> than rutile. Both > >> > vc-relax calculation for rutile and anatase > onverged > >> in 6 scf cycles and > >> > 3 bfgs steps, giving the final enthalpy = > >> -362.7585836890 Ry for rutile > >> > and -725.5447425835 Ry for antase. So the > average > >> energy of [TiO2] unit > >> > is -181.3792918445 Ry for rutile and > -181.386185645875 > >> Ry for anatase. > >> > It looks like anatase is more stable than > rutile. Do > >> you think it was > >> > quite strange? > >> > >> > >> Dear Vega, > >> > >> your results are probably correct. It's a > known failure > >> of LDA and GGA > >> to stabilize anatase more than rutile. > >> > >> nicola > >> > >> -- > >> > --------------------------------------------------------------------- > >> Prof Nicola Marzari Department of Materials > Science and > >> Engineering > >> 13-5066 MIT 77 Massachusetts Avenue > Cambridge MA > >> 02139-4307 USA > >> tel 617.4522758 fax 2586534 marzari at mit.edu > >> http://quasiamore.mit.edu > >> _______________________________________________ > >> Pw_forum mailing list > >> Pw_forum at pwscf.org > >> http://www.democritos.it/mailman/listinfo/pw_forum > > > > > > > > _______________________________________________ > > Pw_forum mailing list > > Pw_forum at pwscf.org > > http://www.democritos.it/mailman/listinfo/pw_forum > > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum
