[Wien] Ghostbands: pushed energy range in case.in1 to 6.3, does this mean there is a problem?
Peter Blaha
pblaha at theochem.tuwien.ac.at
Sat Mar 7 08:24:09 CET 2015
There is a misunderstanding: No, don't take a "mean" energy.
Check also the corresponding charge. When it is large, it is a major
component and needs an energy parameter close to this energy.
>> In case.scf2 you can find under the line :EPH and :EPL
>> the "mean" energy of the P-s states. If they are not close to -0.73
>> (thats where you expand P-s), change the corresponding input value.
>
> For P-s, :EPL and :EPH are -1.34 and -0.43, mean of -0.89, fairly close to
> -0.73?
Together with the large P-s charge in :EPL it tells you, that you should
lower the P-s parameter in case.in1 to -1.34
Whether one sets in addition a second l=0 Eparameter in case.in1 depends on
the E-separation between these EPL and EPH values, corresponding charges
and the sphere radii (the larger the spheres: more probably yes).
Here you have 0.9 Ry difference, but presumably the P-s charge in the upper E-window is
very small and you have a very small spheres. Setting the two
energies to those values might lead to ghostbands and at least at the beginning you
moved one E-parameter up to +6 Ry. As I said previously, you may test it at the end
and set the second Al-s line to 0.30 (no search), so that the actual E-parameter will be EF+0.2
> Other than P-s they are not close. Al-s has -7.24, -0.34, mean of -3.79,
> case.in1 has -7.65.
> O-s has -1.21, -0.30, mean is -0.75, while case.in1 has -1.46. Similarly
> for Al-p and P-p.
Again, there should be l=0 E-parameters close to -7.24 and 1.21, respectively.
In addition there should be definitely a second Al-s line at 0.30, since there are
"real" Al 3s states in the valence region.
> I had mostly read about a supercell with one full core hole. Some of these
> are certainly cells where I do not want to build a larger supercell than I
> have to. Is the HALF a core hole a better choice?
Are you interested in XPS or in XAS. This is a VERY different process where the
excited electron leave the bulk or stays whithin the bulk.
For XPS you are interested just in ONE number (Al-2p ionizationpotential) and
Slaters transition state concept with half a core hole applies.
For XAS you want to simulate a spectrum for a system with one core hole and an additional e- in
the valence band. Use (at least for insulators) a full core hole.
>
> Do I understand correctly that whether I use a HALF core-hole or a full one,
> I then do minimization of the ionic positions again?
No. Electronic spectroscopy is a very fast process and the ions have no time to move
around.
>
> The user-guide says "The energy cut-off specified in lstart during init lapw
> (usually -6.0 Ry) defines the separation
> into core- and band-states (the latter contain both, semicore and valence)."
> How do I get the Al 2p state into the core?
> Do I have to change the cut-off and use .lcore, or is there some way to move
> just the Al 2p state into the core?
Besides an Energy (-X Ry), you can also specify a charge localization criterium
(like 0.999), which will put all states with less charge inside sphere as valence.
Checkout case.outputst to see how much charge each state has inside sphere:
E-up(Ry) E-dn(Ry) Occupancy q/sphere core-state
1S -3.801989 -3.785331 1.00 1.00 0.9922 F
2S -0.236724 -0.003329 1.00 0.00 0.0675 F
>
> PS There was no "reply" button in the archive except "Reply via email". I
> could not find an answer as to how to reply to a post in either the Mail
> Archive FAQ, or the WIEN mail archive.
>
> Thanks,
> David
>
> ---------------------------------------------------------------------------
> At Thu, 05 Mar 2015 22:41:38 -0800, Peter Blaha wrote
> I think you have solved the problem very well.
>
> Due to the small P sphere and the fact, that P-s states are relatively
> high in energy, the two linearization energies must be quite well
> separated. (An alternative would have been to simply remove the second
> l=0 line for P and change to "3" lines only:
> 0.30 3 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> 1 0.30 0.000 CONT 1
> 1 -8.83 0.001 STOP 1
> 0 -0.73 0.002 CONT 1
>
> Two more checks towards the "end of the scf cycle":
> In case.scf2 you can find under the line :EPH and :EPL
> the "mean" energy of the P-s states. If they are not close to -0.73
> (thats where you expand P-s), change the corresponding input value.
>
> If the energy of the P-s states has gone down in energy at the end of the
> scf-cycles, you may
> checkout if you can go down with this second E-s input line from +6 back to
> 2.0
> or even
> back to 0.3 (sometimes such problems are temporary).
>
> PS: If you are interested in Al-2p XPS you should do Slaters transition
> state !
> Put Al 2p into the core and introduce HALF a core hole (compensated by a
> background).
> This gives much better core-eigenvalues that the plain DFT groundstate
> eigenvalues,
> typically lt. 1 % error as compared to 10 % error in comparison with
> experiment.
> In addition, final state screening effects are better accounted for.
>
>
> Am 06.03.2015 um 00:44 schrieb David Olmsted:
>
>
> Ghostbands: pushed energy range in case.in1 to 6.3, does this mean there is
> a problem?
>
> WIEN2k_14.2 (Release 15/10/2014)
> Quad-Core AMD Opteron(tm) Processor 2378
> Linux cluster
> Intel 11.1 compilers with mkl.
>
> The purpose of my computation is to compare predicted XPS spectra for Al 2p
> electon
> for different environments of the Al atom in the Al-P-O-H system.
>
> User: beginner! My first time using WEIN2k. Moderate amount of VASP work.
>
> Issue: ghostbands
>
> GGA-PBE, 48 atoms, K-mesh 6x6x4, no shift. Not spin-polarized.
> Initial cell and positions from relaxed GGA-PBE using VASP, same K-mesh.
>
> RMT from w2web StructGen (3% reduction)
> H 0.63
> O 1.17
> P 1.34
> Al 1.72
>
> RKmax 3.5 to get "effective RKmax" of 6.5 for O.
>
> rmt(min)*kmax = 3.50000
> gmin = 11.11111
> gmax = 20.00000
>
> ------- metavar_v.in0
> TOT XC_PBE (XC_LDA,XC_PBESOL,XC_WC,XC_MBJ,XC_REVTPSS)
>
> NR2V IFFT (R2V)
> 64 120 108 1.00 1 min IFFT-parameters, enhancement factor, iprint
> ---------
>
> For default -6 Ry cutoff for core states, charge was leaking out of RMT
> sphere
> for P 2p states. Final iteration in metavar_v.outputst:
> 14 350
> 14 1.85E-07 1.884765E+00 -8.645384E-01 -8.645386E-01 1.72E-07
> -1.67E-08 1.707034E-01 1.707034E-01
> 1S -153.17082 -153.17082
> 2S -12.78682 -12.78682
> 2P* -9.19366 -9.19366
> 2P -9.12626 -9.12626
> 3S -1.02668 -1.02668
> 3P* -0.40735 -0.40735
> 3P -0.40342 -0.40342
>
> Cutoff set to -9.2 Ry. (Also tried leaving it at -6.0 Ry and touching
> .lcore. Similar results.)
>
> ===============================================================
> ---------------------------- Question -------------------------
> ===============================================================
>
> With the original case.in1 file, had messages for the P atom, L=0:
> (All these messages are from the first run of LAPW2.)
>
> metavar_v.scf2_1: QTL-B VALUE .EQ. 4951.54243 in Band of energy -6.46139
> ATOM= 2 L= 0
>
> increased 0.3 to 2.3 in case.in1, now:
>
> QTL-B VALUE .EQ. 1347.97207 in Band of energy -4.71553 ATOM= 2 L=
> 0
>
> increased it 4.3
>
> QTL-B VALUE .EQ. 602.53449 in Band of energy -2.14697 ATOM= 2 L=
> 0
>
> When I increased it to 6.3, no complaints.
>
> The initial scf run has completed with no warnings; the position
> minimization is still running.
>
> In the mailing list search, there are suggestions to increase the (upper)
> energy range to
> 1.3 or "even 2.0" Ry. That makes me worry about the fact that I had to
> increase it to a much
> larger value. Does this mean something is going wrong?
>
> ------------------------- End of question ------------------------
> =========== case.in1 =============================================
> WFFIL EF=.1268392143 (WFFIL, WFPRI, ENFIL, SUPWF)
> 3.5 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 -7.65 0.001 STOP 1
> 1 0.30 0.000 CONT 1
> 1 -4.81 0.001 STOP 1
> 0.30 4 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 1 0.30 0.000 CONT 1
> 1 -8.83 0.001 STOP 1
> 0 -0.73 0.002 CONT 1
> 0 6.30 0.000 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
> 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
> 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
> 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
> 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
> 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
> 0.30 1 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 0 0.30 0.000 CONT 1
> 0.30 1 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 0 0.30 0.000 CONT 1
> 0.30 1 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 0 0.30 0.000 CONT 1
> 0.30 1 0 (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global
> APW/LAPW)
> 0 0.30 0.000 CONT 1
> K-VECTORS FROM UNIT:4 -12.2 1.5 250 emin / de (emax=Ef+de) /
> nband #red
>
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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
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