[Wien] Ghost bands error in SrTiO3 calculation at high RKmax
Laurence Marks
L-marks at northwestern.edu
Thu Jun 14 13:40:31 CEST 2012
My email was not completely clear. I suggest that you just use the
case.in1 that you sent without other options.
I am not clear what you are trying to do, and if you explain more
someone may be able to help. From the sounds of it you want the
unoccupied DOS to be "more accurate". What is limiting their accuracy
is a number of factors, two of which are:
a) DFT is a ground state model, so a-priori does not give correct
values for unoccupied states, for instance those involved in optical
or other spectroscopies. There are other methods for getting better
values for these but they are quite numerically intensive.
b) Conventional DFT functionals (e.g. PBE) are too covalent. Even for
something as simple as SrTiO3 there is too much hybridization of the
Ti d-levels and the O sp-levels. You can partially correct for this by
using hybrids, for instance the PBE0 on-site method as described in
the user guide or the modified BJ potential.
It may well be that what you want is not achievable, but I am only guessing....
On Wed, Jun 13, 2012 at 10:44 PM, Ye Zhu <ye.zhu at monash.edu> wrote:
> Thanks, Dr. Marks. I will try -in1ef. The default case.in1 does use APW for
> all orbitals, and
> works for my calculation. But just from the manual only the valence d and
> f-orbitals are recommended to use APW (obsolete now?). The following is the
> default case.in1:
> WFFIL EF=.42168 (WFFIL, WFPRI, ENFIL, SUPWF)
> 9.00 10 4 (R-MT*K-MAX; MAX L IN WF, V-NMT
> 0.30 4 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 0 0.30 0.000 CONT 1
> 0 -2.70 0.001 STOP 1
> 1 -1.35 0.002 CONT 1
> 1 0.30 0.000 CONT 1
> 0.30 5 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 0 0.30 0.000 CONT 1
> 0 -4.30 0.001 STOP 1
> 1 -2.54 0.002 CONT 1
> 1 0.30 0.000 CONT 1
> 2 0.30 0.005 CONT 1
> 0.30 3 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 0 -1.46 0.002 CONT 1
> 0 0.30 0.000 CONT 1
> 1 0.30 0.000 CONT 1
> K-VECTORS FROM UNIT:4 -9.0 2.5 42 emin/emax/nband #red
>
> For RMT, I use 2.6 for Sr, 1.95 for Ti and 1.75 for O.
>
> Thanks again.
>
>
>
> On 14 June 2012 12:07, Laurence Marks <L-marks at northwestern.edu> wrote:
>>
>> Your linearization energies look very strange. I suggest that you use
>> the default case.in1 and APW (is there a reason you want to use LAPW?)
>> For most problems that I know of -in1new is now obsolete, replaced by
>> -in1ef (which is done automatically with the default case.in1). Then
>> just increase RKMAX as appropriate, this is more important than
>> fiddling with the linearization energies in most cases.
>>
>> N.B., what RMTs are you using, your Fermi Energy looks low to me.
>>
>> On Wed, Jun 13, 2012 at 8:54 PM, Ye Zhu <ye.zhu at monash.edu> wrote:
>> > Hi all,
>> >
>> > I am running a calculation for SrTiO3 empty DOS using the newest version
>> > of
>> > WIEN2k. An error I got is
>> >
>> > Error in LAPW2
>> > 'l2main' - QTL-B.GT.15., Ghostbands, check scf files
>> >
>> > which occurred during the very first round when I used RKmax = 8. .scf2
>> > file shows:
>> >
>> > QTL-B VALUE .EQ. 143.22898 in Band of energy 0.44165 ATOM=
>> > 1 L= 0
>> > Check for ghostbands or EIGENVALUES BELOW XX messages
>> > Adjust your Energy-parameters for this ATOM and L (or use
>> > -in1new
>> > switch), check RMTs !!!
>> >
>> > :WARN : QTL-B value eq. 143.23 in Band of energy 0.44165
>> > ATOM= 1 L= 0
>> > :WARN : You should change the E-parameter for this atom and
>> > L-value
>> > in case.in1 (or try the -in1new switch)
>> >
>> > and I also found: Energy to separate low and high
>> > energystates: -999.00000
>> >
>> > Similar information is in .output2 : Energy to
>> > separate
>> > semicore and valence states: -999.000000000000
>> >
>> > Why the energy to separate semicore and valence states cannot be found?
>> > I
>> > have tried RKmax = 6, 7, 7.5, 8.5, 9, 10, and all went through without
>> > the
>> > Ghostbands error. But I did see a number of warnings when RKmax > 8 :
>> >
>> > :WAR : 1 EIGENVALUES BELOW THE ENERGY -9.00000
>> > :WAR : 1 EIGENVALUES BELOW THE ENERGY -9.00000
>> > :WAR : 1 EIGENVALUES BELOW THE ENERGY -9.00000
>> >
>> > Is this a Emin problem? These problems at high RKmax make me worry about
>> > my
>> > calculation. The following is my .in1 file
>> >
>> > WFFIL EF=.41905 (WFFIL, WFPRI, ENFIL, SUPWF)
>> > 8.0 10 4 (R-MT*K-MAX; MAX L IN WF, V-NMT
>> > .23 6 0 global e-param with N other choices, napw
>> > 0 0.200 0.000 CONT 0
>> > 0 -2.000 0.002 CONT 0
>> > 1 0.240 0.000 CONT 0
>> > 1 -0.690 0.002 CONT 0
>> > 2 0.267 0.000 CONT 1
>> > 2 1.100 0.000 CONT 1 <<<<
>> > .23 6 0 global e-param with N other choices, napw
>> > 0 0.155 0.000 CONT 0
>> > 0 -3.800 0.002 STOP 0
>> > 1 0.233 0.000 CONT 0
>> > 1 -2.000 0.002 CONT 0
>> > 2 0.200 0.000 CONT 1
>> > 2 0.800 0.000 CONT 1 <<<<<
>> > .23 4 0 global e-param with N other choices, napw
>> > 0 0.277 0.000 CONT 0
>> > 0 -0.750 0.002 CONT 0
>> > 1 0.268 0.000 CONT 0
>> > 1 1.300 0.000 CONT 0 <<<<<<
>> > K-VECTORS FROM UNIT:4 -9.0 3.0 42 emin/emax/nband #red
>> >
>> > Most of the energies were determined using -in1new switch, and I added
>> > high-lying local d-orbitals for Sr (atom1) and Ti (atom2), and local
>> > p-orbital for O (atom3) (highlighted by arrows), hoping to improve the
>> > calculation for empty DOS. The energies of these high-lying orbitals
>> > were
>> > determined from looking at DOS plots and choosing the middle of the
>> > interesting energy range. I increased Emax to 3.0 Ry also for the same
>> > purpose. The following the the .in1 file right after -in1new for
>> > comparison:
>> >
>> > WFFIL EF=.42815 (WFFIL, WFPRI, ENFIL, SUPWF)
>> > 9.00 10 4 (R-MT*K-MAX; MAX L IN WF, V-NMT
>> > .22815 5 0 global e-param with N other choices, napw
>> > 0 0.195 0.000 CONT 0
>> > 0 -1.976 0.000 CONT 0
>> > 1 0.237 0.000 CONT 0
>> > 1 -0.659 0.000 CONT 0
>> > 2 0.267 0.000 CONT 1
>> > .22815 6 0 global e-param with N other choices, napw
>> > 0 0.155 0.000 CONT 0
>> > 0 -3.689 0.001 STOP 0
>> > 1 0.233 0.000 CONT 0
>> > 1 -1.961 0.000 CONT 0
>> > 2 0.198 0.000 CONT 1
>> > 2 -0.766 0.000 CONT 1 <<<<<
>> > .22815 3 0 global e-param with N other choices, napw
>> > 0 0.277 0.000 CONT 0
>> > 0 -0.781 0.000 CONT 0
>> > 1 0.268 0.000 CONT 0
>> > K-VECTORS FROM UNIT:4 -9.0 3.0 42 emin/emax/nband #red
>> >
>> > There is one local d-orbital with -0.766 Ry for Ti which I don't quite
>> > understand. As I care about DOS above Fermi level, I changed it to 0.8
>> > Ry.
>> > The volume optimization worked fine with both .in1 files, but I am
>> > always
>> > worrying about my modifications. Please let me now if anyone knows what
>> > the
>> > problem is or needs any more information.
>> >
>> > Thank you very much,
>> >
>> > Ye
>>
>>
>>
>> --
>> Professor Laurence Marks
>> Department of Materials Science and Engineering
>> Northwestern University
>> www.numis.northwestern.edu 1-847-491-3996
>> "Research is to see what everybody else has seen, and to think what
>> nobody else has thought"
>> Albert Szent-Gyorgi
>> _______________________________________________
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>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
>
--
Professor Laurence Marks
Department of Materials Science and Engineering
Northwestern University
www.numis.northwestern.edu 1-847-491-3996
"Research is to see what everybody else has seen, and to think what
nobody else has thought"
Albert Szent-Gyorgi
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