thanks for your reply ,I changed the lambda=5.0 and used occupations='tetrahedra' but the magnetization still did not converge to the initial value ,but the total energy converged. I do not know what is the problem.
> 2009/3/11 Gabriele Sclauzero <sclauzer at sissa.it> > > >> >> yumin qian wrote: >> > Dear PWSCF users >> > I am doing calculate on the antiferromagnetic ground state of >> > LiNiO2, I want to plot the energy as a function of fixed spin moment of >> > Ni atom. >> > the following is my in put file for pwscf >> > >> > &system >> > ibrav = 0, nat=16 , ntyp= 4, >> > ecutwfc = 35.0, ecutrho = 200.0, >> > occupations='smearing', smearing='gaussian', degauss=0.02 >> >> First of all a word of caution: this value of degauss may not be low >> enough to converge >> the magnetization (even if it is more than enough to converge the total >> energy). Also >> ecutrho may not be high enough to converge total energy, since you're >> using US PPs. >> >> > nspin=2,constrained_magnetization='atomic', >> > starting_magnetization(1)= 0.0, >> > starting_magnetization(2)= 1.8, >> > starting_magnetization(3)=-1.8, >> > starting_magnetization(4)= 0.0, >> > lda_plus_u=.true. >> > Hubbard_U(1)=0.0 >> > Hubbard_U(2)=3.0 >> > Hubbard_U(3)=3.0 >> > Hubbard_U(4)=0.0 >> > / >> > &electrons >> > diagonalization='david', >> > conv_thr = 1.0e-6, >> > mixing_beta = 0.5, >> > / >> > ATOMIC_SPECIES >> > Li *6.914* Li.pbe-n-mt_bw.UPF >> > Ni1 *58.6934* Ni.pbe-n-van.UPF >> > Ni2 *58.6934* Ni.pbe-n-van.UPF >> > O 15.9994 O.pbe-van_bm.UPF >> > >> > and the output file gives >> > >> > >> >> ============================================================================== >> > atom number 5 relative position : -0.1652 0.2839 0.5083 >> > charge : 2.373353 >> > magnetization : 1.544423 >> > magnetization/charge: 0.650735 >> > constrained moment : 1.800000 >> > >> > >> >> ============================================================================== >> > the output file gives a magnetic moment of 1.5444 ,how should I do to >> > make the calculation converge to the starting_magnetization 1.8 ? >> >> You can increase the lambda parameter which premultiplies the penalty >> energy added in >> v_of_rho. In the limit your constraint gets satisfied, the energy should >> not depend on >> which lambda you chose, but you may want to verify this. >> The default should be 1. I think is not enough to force the magnetization >> on the atom. >> >> However, I think that the magnetization of a single atom inside a bulk >> material or in >> general when it forms covalent bonds is not a well defined quantity, so I >> would not care >> too much of the precise number I get for the magnetization, since it may >> well change if I >> change which portion of charge is attributed to which atom (remember that >> you're using a >> plane waves code, and PWs do not know anything about atomic orbitals a >> priori...) >> >> HTH >> >> GS >> >> > >> > I change the starting_magnetization(2) and starting_magnetization(3) >> > from 1.8 to 0.8 , then I will get the E(m) curve. how should I do , >> > does anyone give >> > a suggestion ? >> > -- >> > Sincerely Y. M. Qian >> > Lab.of Condensed Matter Theory and Materials Computation >> > Institute of Physics >> > Chinese Academy of Sciences >> > Tel: + 8610 8264 9147 >> > E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com> <mailto: >> E-Mail%3Ayuminqian at gmail.com <E-Mail%253Ayuminqian at gmail.com>> >> > P.O.Box 603 Beijing 100190 >> > China >> > >> > >> > ------------------------------------------------------------------------ >> > >> > _______________________________________________ >> > Pw_forum mailing list >> > Pw_forum at pwscf.org >> > http://www.democritos.it/mailman/listinfo/pw_forum >> >> -- >> >> >> o ------------------------------------------------ o >> | Gabriele Sclauzero, PhD Student | >> | c/o: SISSA & CNR-INFM Democritos, | >> | via Beirut 2-4, 34014 Trieste (Italy) | >> | email: sclauzer at sissa.it | >> | phone: +39 040 3787 511 | >> | skype: gurlonotturno | >> o ------------------------------------------------ o >> _______________________________________________ >> Pw_forum mailing list >> Pw_forum at pwscf.org >> http://www.democritos.it/mailman/listinfo/pw_forum >> > > > > -- > Sincerely Y. M. Qian > Lab.of Condensed Matter Theory and Materials Computation > Institute of Physics > Chinese Academy of Sciences > Tel: + 8610 8264 9147 > E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com> > P.O.Box 603 Beijing 100190 > China > > -- Sincerely Y. M. Qian Lab.of Condensed Matter Theory and Materials Computation Institute of Physics Chinese Academy of Sciences Tel: + 8610 8264 9147 E-Mail:yuminqian at gmail.com <E-Mail%3Ayuminqian at gmail.com> P.O.Box 603 Beijing 100190 China -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090312/492f943e/attachment.htm
