[Pw_forum] qustions about the initio magnetization of ion

Dr. Shu-jun Hu hushujun at mail.sdu.edu.cn
Mon Jul 6 08:11:15 CEST 2009


Dear all,
I have some qustions about the initio magnetization of ion for LSDA calculation.
In the input file the "starting_magnetization" is used to break the spin symmetry of magnetic system. By specifying such parameters, how does pw.x initio the magnetic moment of certain ions?
Taking transition metal ion Fe for example, if the starting_magnetizaton(Fe)=0.4, how many electrons occupy the spin-up and spin-down channels respectively for the initio wfc? Only the symmetry breaking of 3d electrons are considered in LSDA calculation, or all the valence electrons (both 3d and 4s)?

Such a question concerns about the output information of calculation with constrained magnetization.
During the calculation, I got the output information as:
     atom number   14 relative position :    1.4040   4.1784   3.2357
     charge :     7.082847
     magnetization :          0.239576
     magnetization/charge:    0.033825
     constrained moment :     0.200000
Does the value of "magnetization" (0.239576) represent the magnetic moment of ion, or the polarization? If the latter case, how to derive the magnetic moment in unit of Bohr? 
-------
Another question is about the total energy given by constrained calculations.
I want to compare the total energy of a system with different magnetic moment for certain ions, and find the ground state.
In order to fix magnetic moment at the starting value, lambda = 1000 is setup. That's a large value.
As described in INPUT_PW.html, the penalty energy is introduced at this time. I wonder if the comparison make any sense?
Any reply to any question is appreciated. If you can also guide me to the position of source code refering to the question, that's great!
Best regards
Shujun Hu
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