<div>thanks for your reply ,I changed the lambda=5.0 and used <br> occupations='tetrahedra' but the magnetization still did not converge to the initial value ,but the total energy converged.</div>
<div>I do not know what is the problem.<br><br></div>
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<div class="gmail_quote">2009/3/11 Gabriele Sclauzero <span dir="ltr"><<a href="mailto:sclauzer@sissa.it" target="_blank">sclauzer@sissa.it</a>></span>
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<div><br><br>yumin qian wrote:<br>> Dear PWSCF users<br>> I am doing calculate on the antiferromagnetic ground state of<br>> LiNiO2, I want to plot the energy as a function of fixed spin moment of<br>> Ni atom.<br>
> the following is my in put file for pwscf<br>><br>> &system<br>> ibrav = 0, nat=16 , ntyp= 4,<br>> ecutwfc = 35.0, ecutrho = 200.0,<br>> occupations='smearing', smearing='gaussian', degauss=0.02<br>
<br></div>First of all a word of caution: this value of degauss may not be low enough to converge<br>the magnetization (even if it is more than enough to converge the total energy). Also<br>ecutrho may not be high enough to converge total energy, since you're using US PPs.<br>
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<div><br>> nspin=2,constrained_magnetization='atomic',<br>> starting_magnetization(1)= 0.0,<br>> starting_magnetization(2)= 1.8,<br>> starting_magnetization(3)=-1.8,<br>> starting_magnetization(4)= 0.0,<br>
> lda_plus_u=.true.<br>> Hubbard_U(1)=0.0<br>> Hubbard_U(2)=3.0<br>> Hubbard_U(3)=3.0<br>> Hubbard_U(4)=0.0<br>> /<br>> &electrons<br>> diagonalization='david',<br>> conv_thr = 1.0e-6,<br>
> mixing_beta = 0.5,<br>> /<br>> ATOMIC_SPECIES<br>> Li *6.914* Li.pbe-n-mt_bw.UPF<br>> Ni1 *58.6934* Ni.pbe-n-van.UPF<br>> Ni2 *58.6934* Ni.pbe-n-van.UPF<br>> O 15.9994 O.pbe-van_bm.UPF<br>
><br>> and the output file gives<br>><br>> ==============================================================================<br>> atom number 5 relative position : -0.1652 0.2839 0.5083<br>> charge : 2.373353<br>
> magnetization : 1.544423<br>> magnetization/charge: 0.650735<br>> constrained moment : 1.800000<br>><br>> ==============================================================================<br>
> the output file gives a magnetic moment of 1.5444 ,how should I do to<br>> make the calculation converge to the starting_magnetization 1.8 ?<br><br></div></div>You can increase the lambda parameter which premultiplies the penalty energy added in<br>
v_of_rho. In the limit your constraint gets satisfied, the energy should not depend on<br>which lambda you chose, but you may want to verify this.<br>The default should be 1. I think is not enough to force the magnetization on the atom.<br>
<br>However, I think that the magnetization of a single atom inside a bulk material or in<br>general when it forms covalent bonds is not a well defined quantity, so I would not care<br>too much of the precise number I get for the magnetization, since it may well change if I<br>
change which portion of charge is attributed to which atom (remember that you're using a<br>plane waves code, and PWs do not know anything about atomic orbitals a priori...)<br><br>HTH<br><br>GS<br>
<div><br>><br>> I change the starting_magnetization(2) and starting_magnetization(3)<br>> from 1.8 to 0.8 , then I will get the E(m) curve. how should I do ,<br>> does anyone give<br>> a suggestion ?<br>> --<br>
> Sincerely Y. M. Qian<br>> Lab.of Condensed Matter Theory and Materials Computation<br>> Institute of Physics<br>> Chinese Academy of Sciences<br>> Tel: + 8610 8264 9147<br></div>> <a href="mailto:E-Mail%3Ayuminqian@gmail.com" target="_blank">E-Mail:yuminqian@gmail.com</a> <mailto:<a href="mailto:E-Mail%253Ayuminqian@gmail.com" target="_blank">E-Mail%3Ayuminqian@gmail.com</a>><br>
<div>> P.O.Box 603 Beijing 100190<br>> China<br>><br>><br></div>> ------------------------------------------------------------------------<br>><br>> _______________________________________________<br>
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<br>--<br><br><br>o ------------------------------------------------ o<br>| Gabriele Sclauzero, PhD Student |<br>| c/o: SISSA & CNR-INFM Democritos, |<br>| via Beirut 2-4, 34014 Trieste (Italy) |<br>
| email: <a href="mailto:sclauzer@sissa.it" target="_blank">sclauzer@sissa.it</a> |<br>| phone: +39 040 3787 511 |<br>| skype: gurlonotturno |<br>
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<div class="h5"><br><br clear="all"><br>-- <br>Sincerely Y. M. Qian <br>Lab.of Condensed Matter Theory and Materials Computation <br>Institute of Physics <br>Chinese Academy of Sciences<br>Tel: + 8610 8264 9147<br><a href="mailto:E-Mail%3Ayuminqian@gmail.com" target="_blank">E-Mail:yuminqian@gmail.com</a> <br>
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<div class="h5">P.O.Box 603 Beijing 100190<br>China <br><br></div></div></blockquote></div><br><br clear="all"><br>-- <br>Sincerely Y. M. Qian <br>Lab.of Condensed Matter Theory and Materials Computation <br>Institute of Physics <br>
Chinese Academy of Sciences<br>Tel: + 8610 8264 9147<br><a href="mailto:E-Mail%3Ayuminqian@gmail.com">E-Mail:yuminqian@gmail.com</a> <br>P.O.Box 603 Beijing 100190<br>China <br><br>