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 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 -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090312/2ffce358/attachment.htm
