[Wien] Lapw1 error

Peter Blaha pblaha at theochem.tuwien.ac.at
Thu May 12 07:35:41 CEST 2005 

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
> > ------------------------------------------------------------------
> > Phys.-Techn. Institute of       | Tel.(home):   7 (3412) 442118
> > Ural Br. of Russian Ac. of Sci. | Tel.(office): 7 (3412) 218988
> > 426001 Izhevsk, ul.Kirova 132   | Fax:          7 (3412) 250614
> > RUSSIA                          | E-mail: lyu at otf.fti.udmurtia.su
> > ------------------------------------------------------------------
> > http://fti.udm.ru/ltt/personals/dobysh.htm
> > ------------------------------------------------------------------
> > 
> > _______________________________________________
> > Wien mailing list
> > Wien at zeus.theochem.tuwien.ac.at
> > http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> > 
> >  
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
> 


                                      P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
--------------------------------------------------------------------------

More information about the Wien mailing list