[Wien] convergence problem :: runsp_c_lapw

[Peter Blaha]

The reason for your problems has nothing to do with "mixing".

Your :DIS s already quite small, but how can :FER change from
one iteration to the next  by 1 Ry ???

Most likely there must be other reasons like some ghostbands appear,
the fermi-energy deterination did not work out correctly, ....
states felt below EMIN, the number of electrons is ne. sum of nuclear
charges, ...

Check :NEC01    Was it (almost) the same in all iterations ?
Check :ENE   any warnings ... ???

Look and "count" your states in the scf file, when your EF=-0.7 Ry
and compare it with an iteration where EF is "normal".

In order to do this, you should "understand" your low lying states
(can be found from the E-parameters in the scf-file and the multiplicity
of the corresponding atom. As  short example: Suppose you find for your first
atom (a Ti) a low E-s parameter near -4.0 Ry and MULT=4 for the first atom, so you
should find 4 eigenvalues around -4Ry (eg. the Ti 3s). Similarly, Ti should also
3p semicore states, eg. near -2.5 Ry, thus you should find 12 eigenvalues around
that energy. ....

Hope this helps, otherwise I need 2 iterations of the scf file where
those EF changes happen.

PS: If you see such problems it could mean that you should start over, since such a density
will NEVER converge.

Am 24.04.2014 12:25, schrieb Martin Gmitra:
> Dear Wien2k users,
>
> I am doing calculations of a hexaboride films invoking: runsp_c_lapw -so -eece
> My problem is two fold:
>
> (i) SCF calculations successfully converged for thin films (9 atomic units) and bulk systems. I do have a problem to converge a thicker film (11 atomic units) even TEMP
> broadening of 0.02 is used. The observations after 800 iterations are following:
>
> (1) fermi energy is jumping (roughly) between two values
> :FER  : F E R M I - ENERGY(FERMI-SM.)=   0.3682855520
> :FER  : F E R M I - ENERGY(FERMI-SM.)=   0.3682855520
> :FER  : F E R M I - ENERGY(FERMI-SM.)=  -0.7779431003
> :FER  : F E R M I - ENERGY(FERMI-SM.)=  -0.7779431003
> :FER  : F E R M I - ENERGY(FERMI-SM.)=   0.3683943150
> :FER  : F E R M I - ENERGY(FERMI-SM.)=   0.3683943150
> :FER  : F E R M I - ENERGY(FERMI-SM.)=  -0.7767634505
> :FER  : F E R M I - ENERGY(FERMI-SM.)=  -0.7767634505
>
> (2) charge distance non uniformly oscillates between 0.1 and 0.001
> :DIS  :  CHARGE DISTANCE       ( 1.1067771 for atom    4 spin 1)      0.1064425
> :DIS  :  CHARGE DISTANCE       ( 0.0059078 for atom    6 spin 1)      0.0013328
> :DIS  :  CHARGE DISTANCE       ( 0.0092322 for atom    6 spin 1)      0.0015769
> :DIS  :  CHARGE DISTANCE       ( 0.0092664 for atom    6 spin 1)      0.0015106
> :DIS  :  CHARGE DISTANCE       ( 0.5478509 for atom    4 spin 1)      0.0466613
> :DIS  :  CHARGE DISTANCE       ( 0.0078766 for atom    6 spin 1)      0.0014700
> :DIS  :  CHARGE DISTANCE       ( 0.9814094 for atom    4 spin 1)      0.0939173
> :DIS  :  CHARGE DISTANCE       ( 0.0070829 for atom    6 spin 1)      0.0015672
> :DIS  :  CHARGE DISTANCE       ( 0.0411319 for atom    4 spin 2)      0.0053433
> :DIS  :  CHARGE DISTANCE       ( 0.0072009 for atom    6 spin 1)      0.0014308
> :DIS  :  CHARGE DISTANCE       ( 0.1357701 for atom    4 spin 2)      0.0150618
>
> (3) magnetic moments are zero within spheres whereas there is
> :MMTOT: SPIN MAGNETIC MOMENT IN CELL   =    -0.00010
> :MMINT: MAGNETIC MOMENT IN INTERSTITIAL =   -0.00003
>
> (4) my case.inm
> BROYD  0.0   YES  (BROYD/PRATT, extra charge (+1 for additional e), norm)
> 0.005           mixing FACTOR for BROYD/PRATT scheme
> 1.00  1.00      PW and CLM-scaling factors
> 9999  8         idum, HISTORY
>
> :MIX  :   MSEC3  REGULARIZATION: 2.50E-04  GREED: 0.005  Newton 1.000
> with PRATT after 100 iterations
> MIX  :   PRATT  REGULARIZATION: 2.50E-04  GREED: 0.005
>
> Do you have any hints how to converge the calculations?
>
> (ii) I am running the calculations with version 12.1. The runsp_c_lapw script has been updated (debugged) in version 13.1 but SCF diverges in my cases (thin and thicker films).
>
> Does anybody experience similar problem?
>
> Best regards,
> Martin Gmitra
> Uni Regensburg
>
>
>
>
>
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-- 
-----------------------------------------
Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
-----------------------------------------