Hi, Thank you for your kindly reply.
>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. >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? 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: 801 -32180.0924 -32180.0919 -32180.0919 0.0011 -3.0670 -3.0670 siesta: 802 -32180.0924 -32180.0919 -32180.0919 0.0011 -3.0670 -3.0670 siesta: 803 -32180.0925 -32180.0920 -32180.0920 0.0011 -3.0670 -3.0670 siesta: 804 -32180.0925 -32180.0920 -32180.0920 0.0011 -3.0670 -3.0670 siesta: 805 -32180.0926 -32180.0921 -32180.0921 0.0011 -3.0670 -3.0670 siesta: 806 -32180.0925 -32180.0921 -32180.0921 0.0011 -3.0670 -3.0670 siesta: 807 -32180.0926 -32180.0921 -32180.0921 0.0011 -3.0670 -3.0670 siesta: 808 -32180.0926 -32180.0921 -32180.0921 0.0011 -3.0670 -3.0670 siesta: 809 -32180.0926 -32180.0921 -32180.0921 0.0011 -3.0670 -3.0670 siesta: 810 -32180.0927 -32180.0922 -32180.0922 0.0011 -3.0669 -3.0669 siesta: 811 -32180.0927 -32180.0923 -32180.0923 0.0011 -3.0669 -3.0669 siesta: 812 -32180.0928 -32180.0923 -32180.0923 0.0011 -3.0669 -3.0669 siesta: 813 -32180.0929 -32180.0924 -32180.0924 0.0011 -3.0669 -3.0669 siesta: 814 -32180.0927 -32180.0923 -32180.0923 0.0011 -3.0669 -3.0669 siesta: 815 -32180.0928 -32180.0924 -32180.0924 0.0011 -3.0669 -3.0669 siesta: 816 -32180.0928 -32180.0924 -32180.0924 0.0011 -3.0669 -3.0669 siesta: 817 -32180.0929 -32180.0925 -32180.0925 0.0011 -3.0669 -3.0669 siesta: 818 -32180.0928 -32180.0923 -32180.0923 0.0011 -3.0669 -3.0669 siesta: 819 -32180.0928 -32180.0924 -32180.0924 0.0011 -3.0669 -3.0669 siesta: 820 -32180.0929 -32180.0925 -32180.0925 0.0011 -3.0669 -3.0669 siesta: 821 -32180.0929 -32180.0925 -32180.0925 0.0011 -3.0669 -3.0669 siesta: 822 -32180.0929 -32180.0925 -32180.0925 0.0010 -3.0669 -3.0669 siesta: 823 -32180.0930 -32180.0926 -32180.0926 0.0010 -3.0669 -3.0669 siesta: 824 -32180.0931 -32180.0927 -32180.0927 0.0010 -3.0669 -3.0669 siesta: 825 -32180.0931 -32180.0927 -32180.0927 0.0010 -3.0669 -3.0669 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 ...... ---------------------------------------------------------------------------------------------------------------------- I'd like to increase the DM.MixingWeight to 0.3 to accelerate the calculation. Is it correct? 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. > BTW, whether my setting of the antiferromagnetism is correct. Best, On Mon, Jul 26, 2010 at 2:03 AM, <[email protected]> wrote: > > Dear all, > > > > I intend to calculate the exchange integral of CdFe2O4, so I need the > > energy > > of four magnetic structures, one ferromagnetism and three > > antiferromagnetism. The ferromagnetic system have finished in 40 hours, > > but > > the antiferromagnetic system have taken about 170 hours. The calculation > > converged so slowly and there was already 700 interations. > > Hi, > it is normal that as you increase your system to include many > equivalent (or almost) atoms, the convergence becomes difficult, > because of electrons flopping between nearly degenerate states. > So sometimes you need just patience and very small mixnig parameter. > The crucial question is, is your calculation on the right way > and simply converges slowly, or is it wildly fluctuating. > To get an idea, look at the results (Mulliken charges; DOS) > underway, after some number of iterations. > > Good luck > > Andrei Postnikov > -- Bin Shao College of Information Technical Science, Nankai University 94 Weijin Rd. Nankai Dist. Tianjin 300071, China Email: [email protected]
