[Wien] Lapw1 error

L. D. Marks L-marks at northwestern.edu
Thu May 12 14:30:33 CEST 2005 

In some cases (and this may be one) when there is a deep semi-core state
the -in1new switch is not the cure because it ends up giving an energy
slightly too high (compare the eigenvalues in case.scf1 to what
case.in1new has) and this can lead to ghostbands. One solution is to edit
by hand the case.in1 file.

On Thu, 12 May 2005, EB Lombardi wrote:

> Dear Prof Blaha
>
> In all cases, I use a separation energy of -10 Ry in lstart to place the
> P-2p in the valence as LO's (to prevent charge leakage, as you
> mentioned). Using this approach the charge leakage is:
> For P:
>  TOTAL CORE-CHARGE:                    4.000000
>  TOTAL CORE-CHARGE INSIDE SPHERE:      3.995122
>  TOTAL CORE-CHARGE OUTSIDE SPHERE:     0.004878
> For C atoms:
>  TOTAL CORE-CHARGE:                    2.000000
>  TOTAL CORE-CHARGE INSIDE SPHERE:      1.999732
>  TOTAL CORE-CHARGE OUTSIDE SPHERE:     0.000268
>
> The leakage for P is still an order of magnitude larger than for C.
>
> The .in1c file contains (default input) for P:
>   0.30    4  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
>  1    0.30      0.000 CONT 1
>  1   -8.80      0.005 STOP 1
>  0   -0.79      0.010 CONT 1
>  0    0.30      0.000 CONT 1
>
> For the sake of completeness I am attaching the struct files, etc. which
> I attached to the original e-mail.
>
> Note: for the 'plain' LAPW calculation mentioned in my previous e-mail
> (3.1), the fermi level lies at 1.30409 Ry. So according to the FAQ, I
> also tried replacing all '0.30' entries in .in1c with '1.00'. This does
> not solve the problem either, but results in ghost bands at -2.2662 and
> -2.2663 Ry.
>
> Best regards
> Enrico
>
> --
> Dr E B Lombardi
> Physics Department
> University of South Africa
> P.O. Box 392
> 0003 UNISA
> South Africa
> Tel: +27 (0)12 429-8027
> Fax: +27 (0)12 429-3643
> e-mail: lombaeb at science.unisa.ac.za
>
>
>
>
> Peter Blaha wrote:
>
> >Just a guess:
> >
> >Have you checked for any core leakage of the P site ?
> >Check case.outputst for corresponding WARNINGS.
> >With such small spheres it might be that you need to decrease the -6.0 Ry
> >core-valence seperation energy and include P-2p (maybe even 2s) states in
> >the bandstructure.
> >Otherwise the valence states are not strickly orthogonal to the core and
> >this leads to ghostbands.
> >
> >
> >
> >>Dear Lyudmila and Wien authors.
> >>
> >>Regarding the previous 'ghost band' errors I mentioned in the previous e-mails
> >>on this topic:
> >>
> >>1.  There has been an additional error in the APW calculation (using
> >>unmodified .in1c) which I did not notice originally. In the scf files the
> >>following suspicious lines occur:
> >>QTL-B VALUE .EQ. **********   in Band of energy    0.00000
> >>QTL-B VALUE .EQ. **********   in Band of energy    0.00000
> >>Similarly for a mixed APW/LAPW run (see below):
> >>QTL-B VALUE .EQ.    2.35833   in Band of energy    0.00000
> >>QTL-B VALUE .EQ.    2.35913   in Band of energy    0.00000
> >>
> >>The problem is  that there is no band of energy 0.00000.
> >>
> >>
> >>2.   I tried your suggestion of using a value of -0.2 Ry for the P_s LO (using
> >>APW). This results in a similar crash, with a ghost band at -1.307337 Ry.
> >>(the original unmodified APW run had a ghost band at -3.34806 eV)
> >>
> >>3.   I also tried several other combinations, none of which worked, as
> >>follows:
> >>
> >>3.1:   When using LAPW rather than APW for all atoms (default .in1c), the SCF
> >>cycles converge for the initial geometry structure only. However, when using
> >>"min -p -sp -s 1" for a geometry optimization, lapw2 crashes again in the
> >>first SCF cycle of the new geometry, with many ghost bands at -0.39479,
> >>-0.38044, +0.26593, +0.28952, +0.33388, +0.37419, +0.41470, ..........  Ry
> >>
> >>3.2:   When mixing LAPW for the P-s orbitals and APW for everything else, the
> >>results are similar to 3.1 with the SCF cycles converging for the initial
> >>geometry, but crashing in the first SCF cycle of the second geometry
> >>optimization step with ghost bands at +0.20051, +0.52656, +0.79082, +1.25045
> >>Ry.
> >>
> >>3.3   Changing sphere sizes: When using plain LAPW with default input, but
> >>changing the sphere sizes (Rmt_C from 1.30au to 1.37au,   Rmt_P from 1.42au to
> >>1.40au), this results in a crash in the 5th SCF cycle of the initial geometry
> >>with a message of "FORTRAN STOP L2main - QTL-B Error".
> >>This is an "improvement" since that lapw2 is able to stop with an error
> >>message, rather than just crashing on the ******* in the *.help_ files. The
> >>QTL errors are not so large either. This case is rather perplexing since the
> >>sphere size of P was reduced, while the sphere sizes of the C atoms were
> >>increased.
> >>
> >>For the 5th SCF cycle, the scf files contained:
> >>phos.scf2dn:   QTL-B VALUE .EQ.    6.99287   in Band of energy    0.15828
> >>phos.scf2dn_1:   QTL-B VALUE .EQ.    4.61602   in Band of energy    0.07087
> >>phos.scf2dn_2:   QTL-B VALUE .EQ.    4.55460   in Band of energy    0.63894
> >>phos.scf2dn_3:   QTL-B VALUE .EQ.    3.96843   in Band of energy    0.30243
> >>phos.scf2dn_4:   QTL-B VALUE .EQ.    6.99287   in Band of energy    0.15828
> >>phos.scf2p:   QTL-B VALUE .EQ.    6.99287   in Band of energy    0.15828
> >>phos.scf2up_1:   QTL-B VALUE .EQ.    5.72604   in Band of energy    0.05845
> >>phos.scf2up_2:   QTL-B VALUE .EQ.    5.74549   in Band of energy    0.62481
> >>phos.scf2up_3:   QTL-B VALUE .EQ.    4.91945   in Band of energy    0.28777
> >>phos.scf2up_4:   QTL-B VALUE .EQ.    7.45940   in Band of energy    0.14799
> >>
> >>Note: calculations of other impurities with the same small C spheres had no
> >>problems.
> >>
> >>Any suggestions would be welcome
> >>
> >>Best regards
> >>
> >>Enrico
> >>
> >>
> >>Lyudmila Dobysheva wrote:
> >>
> >>
> >>
> >>>Dear Enrico,
> >>>
> >>>So, the APW+lo makes the first density not good, as there appeared the level
> >>>with -3.34 Ry. I have looked in my old calculations (pure phosphorus and
> >>>alloys with phosphorus) and found that I was completely wrong: these
> >>>phosphorus s-electrons should be in the valence band. I mixed them with P2s.
> >>>The APW+lo calculation in the first iteration is wrong,  the -0.79 which
> >>>comes from the atomic density estimate is more correct. Now I think that it
> >>>is just opposite to my first guess - too low, in my calculations the valence
> >>>band starts at -0.2 Ry and these P s-electrons should lie there. The wrong
> >>>linearization energy (too low!) gave a ghost at -3.34 Ry. The LAPW scheme
> >>>has apparently a wider interval of energy where linearization works well,
> >>>and does not give the ghost, and the APW+lo fails. So, I think that now, if
> >>>you can calculate with the LAPW scheme, you can obtain a convergent
> >>>calculation in it, and then try to continue with APW+lo. And as a test it
> >>>would be very interesting to make a calculation APW+lo at -0.2 Ry or near,
> >>>and look at the result, please write me the result - my settings of the
> >>>system do not allow me to repeat calculation of your system quickly.
> >>>By the way, I was using then:
> >>> 0.30    3  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> >>>APW/LAPW)
> >>>0   -0.79      0.010 CONT 0
> >>>0    0.30      0.000 CONT 0
> >>>1    0.30      0.000 CONT 1
> >>>
> >>>This is a good observation, I'll remember that sometimes APW+lo and LAPW may
> >>>give such different results at the first stages.
> >>>
> >>>Best regards
> >>> Lyudmila Dobysheva
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> >>
> >
> >
> >                                      P.Blaha
> >--------------------------------------------------------------------------
> >Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
> >Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
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>

-----------------------------------------------
Laurence Marks
Department of Materials Science and Engineering
MSE Rm 2036 Cook Hall
2220 N Campus Drive
Northwestern University
Evanston, IL 60201, USA
Tel: (847) 491-3996 Fax: (847) 491-7820
email: L - marks @ northwestern . edu
http://www.numis.northwestern.edu
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