I have another question.In some papers, they said ‘The potential and charge 
density in the muffin-tin (MT) spheres are expanded in spherical harmonics with 
lmax = 8 and non-spherical components up to lmax = 6.’

I don’t know how to set different lmax value during the calculation.  Can you 
tell me how to do ?

This is a bit sloppy/wrong formulation in these papers, as it makes no sense to talk about in a "charge density expansion" about different l values. Everything beyond l=0 is "non-spherical".

We can set the max. l-expansion for the wave functions in the spherical part of the hamiltonian <psi|V_sph|psi>, which is by default=10 in case.in1 (second line). Probably they reduced it to 8 in this paper (don't go below 8)

We can also set the max l-expansion in the wf. for the nonspherical part of H <psi|V_nsph|psi>, and this is 4 by default (again second line of in1).
Larger values will lead to much longer cpu time.

The expansion of charge density and potential is set in case.in2, in the LM-list. By default this goes to L=6




Date: Mon, 29 Feb 2016 18:40:25 +0100
From: t...@theochem.tuwien.ac.at
To: wien@zeus.theochem.tuwien.ac.at
Subject: Re: [Wien] How to get accurate GAP using BJ or mBJ methods?

The fundamental problem of DFT is to be an approximate method whatever
is the xc functional/potential that is used.

Anyway, if you really need band structure for your compounds with correct
band gap, then you can empirically adjust the parameter c of the mBJ
potential until the desired band gaps is obtained. For this, you need
to create the file case.in0abp.
For instance if you want to fix c to 1.2, the case.in0abp should be like
this (see Sec. 4.5.9 of the UG):
1.2
0.0
1.0

F. Tran

On Mon, 29 Feb 2016, JingQun wrote:


Dear all,

I am running wien 14.2 on a machine with operating system centos 6.5, fortran 
compiler ifort.

I want to calculate the electronic structures of borates (such as BBO, KBBF, 
LBO, and so on)and get accurate GAP using BJ or mBJ methods. During the 
calculation, I have encountered some problems. They are:

1, Take KBBF for example. The bandgap of KBBF is 8.0 eV (the UV cutoff edge is 
about 155 nm).  During the calculation, the unit-cell parameters and atomic 
coordinates were obtained from XRD, and the RMT were set as K (2.50), Be(1.28), 
B(1.19), O(1.38)
F(1.56). The core electron states were separated from the valence states by 
-8.0 Ry, and the Rkmax was set as 5.0. The Irreducible Brillouin Zon was 
sampled at 500 k-points without shifted meshes, and the convergent condition 
for SCF was set as 10E(-5). In
order to get accurate GAP as described elsewhere, a mBJ method was used. While 
unlike many other successful example, the bandgap obtained is either larger or 
smaller than the experimental values. That is to say, when I chose ‘Original 
mBJ values (Tran,Blaha
PRL102,226401)’to calculate, the GAP of KBBF is about 11.504 eV, much larger 
than the experimental values (8.0 eV), while when I chose ‘Unmodified BJ 
potential (Becke,Johnson J.Chem.Phys 124,221101’, the result is 7.301 eV, 
smaller than experimental values.
Can anyone kindly tell me how to get accurate bandgap value of borates ?

PS: The KBBF.struct, KBBF.in1c, KBBF.in2c were added as attachment.

KBBF.struct

blebleble
R   LATTICE,NONEQUIV.ATOMS   5  155 R32
MODE OF CALC=RELA unit=bohr
  8.364065  8.364065 35.454261 90.000000 90.000000120.000000
ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT= 4
K          NPT=  781  R0=.000050000 RMT= 2.50000     Z:  19.00000
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.72172000 Y=0.72172000 Z=0.72172000
          MULT= 2          ISPLIT= 4
      -2: X=0.27828000 Y=0.27828000 Z=0.27828000
F          NPT=  781  R0=.000100000 RMT= 1.56        Z:   9.00000
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -3: X=0.80242000 Y=0.80242000 Z=0.80242000
          MULT= 2          ISPLIT= 4
      -3: X=0.19758000 Y=0.19758000 Z=0.19758000
Be         NPT=  781  R0=.000100000 RMT= 1.28        Z:   4.00000
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -4: X=0.50000000 Y=0.19045000 Z=0.80955000
          MULT= 3          ISPLIT= 8
      -4: X=0.80955000 Y=0.50000000 Z=0.19045000
      -4: X=0.19045000 Y=0.80955000 Z=0.50000000
O          NPT=  781  R0=.000100000 RMT= 1.38        Z:   8.00000
LOCAL ROT MATRIX:    0.0000000 0.5000000 0.8660254
                     0.0000000-0.8660254 0.5000000
                     1.0000000 0.0000000 0.0000000
ATOM  -5: X=0.50000000 Y=0.50000000 Z=0.50000000
          MULT= 1          ISPLIT= 4
B          NPT=  781  R0=.000100000 RMT= 1.19        Z:   5.00000
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
   6      NUMBER OF SYMMETRY OPERATIONS
-1 0 0 0.00000000
 0 0-1 0.00000000
 0-1 0 0.00000000
       1
 0-1 0 0.00000000
-1 0 0 0.00000000
 0 0-1 0.00000000
       2
 0 0-1 0.00000000
 0-1 0 0.00000000
-1 0 0 0.00000000
       3
 0 1 0 0.00000000
 0 0 1 0.00000000
 1 0 0 0.00000000
       4
 0 0 1 0.00000000
 1 0 0 0.00000000
 0 1 0 0.00000000
       5
 1 0 0 0.00000000
 0 1 0 0.00000000
 0 0 1 0.00000000
       6

KBBF.in1c

WFFIL  EF=-.100583812400   (WFFIL, WFPRI, ENFIL, SUPWF)
  5.00       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   -2.30      0.002 CONT 1
 0    0.30      0.000 CONT 1
 1   -1.08      0.002 CONT 1
 1    0.30      0.000 CONT 1
  0.30    3  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
 0   -1.90      0.002 CONT 1
 0    0.30      0.000 CONT 1
 1    0.30      0.000 CONT 1
  0.30    2  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
 0    0.30      0.000 CONT 1
 0   -7.51      0.001 STOP 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    2  0      (GLOBAL E-PARAMETER WITH n OTHER CHOICES, global APW/LAPW)
 0    0.30      0.000 CONT 1
 1    0.30      0.000 CONT 1
K-VECTORS FROM UNIT:4  -11.0       1.5   54   emin / de (emax=Ef+de) / nband

KBBF.in2c

TOT             (TOT,FOR,QTL,EFG,FERMI)
  -14.00   52.00   0.50 0.05  1   EMIN, NE, ESEPERMIN, ESEPER0, iqtlsave
TETRA    0.000      (GAUSS,ROOT,TEMP,TETRA,ALL      eval)
  0 0  2 0 -3 3  4 0  4 3 -5 3  6 0  6 3  6 6
  0 0  1 0  2 0  3 0  3 3 -3 3  4 0  4 3 -4 3  5 0  5 3 -5 3  6 0  6 3 -6 3  6 
6 -6 6
  0 0  1 0  2 0  3 0  3 3 -3 3  4 0  4 3 -4 3  5 0  5 3 -5 3  6 0  6 3 -6 3  6 
6 -6 6
  0 0  1 0  2 0  2 2 -2 2  3 0  3 2 -3 2  4 0  4 2 -4 2  4 4 -4 4  5 0  5 2 -5 
2  5 4 -5 4  6 0  6 2 -6 2  6 4 -6 4  6 6 -6 6
  0 0  2 0 -3 3  4 0  4 3 -5 3  6 0  6 3  6 6
 14.00          GMAX
NOFILE        FILE/NOFILE  write recprlist

2, In some papers, they said ‘The potential and charge density in the 
muffin-tin (MT) spheres are expanded in spherical harmonics with lmax = 8 and 
non-spherical components up to lmax = 6.’I don’t know how to set different lmax 
value during the calculation.
Can anyone tell me how to do ?

Thanks very much.

Yours

Qun Jing







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