Dear Prof. Postnikov, I set WriteMullikenPop 1 and I can check the Mulliken charges following the instruction in your lecture after the calculation finished. I found the magnetic moment raise from the 3d electrons in the Fe atom as expect.
But I still don't know how to check the Mulliken charges when the job is running and further judge the convergence of the calculation, since I can not find anything about the Mulliken charges in the output file in the process. Thank you in advance! Best regards, On Mon, Jul 26, 2010 at 4:23 PM, Bin Shao <[email protected]> wrote: > Dear Prof. Postnikov, > > Thank you for your suggestion and the excellent lecture is what I need now, > thank you very much! > > Best regards, > > > On Mon, Jul 26, 2010 at 3:35 PM, <[email protected]> wrote: > >> >> > >> >>it is normal that as you increase your system to include many >> >> >equivalent (or almost) atoms >> > >> > I do not understand why many equivalent atoms will affect the >> convergence. >> >> Hi, >> >> I explained it already: >> >> because of electrons flopping between nearly degenerate states. >> In other words, the states just under the Fermi energy can be >> occupied in different way, and the electrons are just shifted around, >> without reaching the convergence. >> >> >>To get an idea, look at the results (Mulliken charges; DOS) >> >> >underway, after some number of iterations. >> > >> > Could you give me some ditails about checking the results of Mulliken >> > charges or DOS after some number of iterations? >> >> You print out Mulliken charges, there is a switch for it. >> You look at them and think whether they are as you expect >> (i.e., the atoms which ought to be magnetic are magnetic, >> and in a right way). >> Check if you find anything useful in the following lecture: >> http://www.home.uni-osnabrueck.de/apostnik/Lectures/APostnikov-Magnets.pdf >> >> > Usually, I just check the following information of the scf. >> >> >--------------------------------------------------------------------------- >> > siesta: iscf Eharris(eV) E_KS(eV) FreeEng(eV) dDmax Ef_up >> > Ef_dn(eV) >> > ...... >> > siesta: 799 -32180.0924 -32180.0919 -32180.0919 0.0011 -3.0670 >> > -3.0670 >> > siesta: 800 -32180.0924 -32180.0919 -32180.0919 0.0011 -3.0670 >> > -3.0670 >> ... >> > siesta: 826 -32180.0929 -32180.0925 -32180.0925 0.0010 -3.0669 >> > -3.0669 >> > siesta: 827 -32180.0931 -32180.0927 -32180.0927 0.0010 -3.0668 >> > -3.0668 >> > ...... >> >> This is good but does not tell you anything but that your calculation >> is not quite converged. >> In fact it doesn't look like a divergence, and the Fermi level(s) are >> not a priori unreasonable. So, before doing anything else, try >> to make sense out of your calculation (position of bands, magnetic >> moments, etc.) >> >> >> ---------------------------------------------------------------------------- >> > >> > I'd like to increase the DM.MixingWeight to 0.3 to accelerate the >> > calculation. Is it correct? >> >> If it smoothly converges to a right solution, that's fine. >> But I'd rather suggest, with system as large as yours, to be >> more prudent. 0.3 is a huge mixing weight. >> >> > Since you said I need a small mixing >> > parameter, >> > how to understand the mixing parameter? I read some notes about >> > DM.MxingWeight, but there is still something puzzled me. >> > >> > alpha has to be small (0.1-0.3) for insulator and semiconductors, >> > tipically much smaller for metals. >> >> Yes; what is the problem? In metals you need a good sampling of states >> near the Fermi level; imagine you have a narrow band which shifts >> across the E_f; then you'd like to damp the resulting fluctuations. >> In semiconductors the situation is (usually) less critical because >> bands are either occupied or empty. >> >> > BTW, whether my setting of the antiferromagnetism is correct. >> >> I don't know the structure, sorry. Apart from this - yes; >> some Fe atoms marked "+" and others "-", as it should be. >> >> Best regards >> >> Andrei Postnikov >> >> > > > -- > Bin Shao > College of Information Technical Science, Nankai University > 94 Weijin Rd. Nankai Dist. Tianjin 300071, China > Email: [email protected] > -- Bin Shao, Ph.D. Candidate College of Information Technical Science, Nankai University 94 Weijin Rd. Nankai Dist. Tianjin 300071, China Email: [email protected]
