The ABINIT Users Mailing List ( CLOSED )

[Xavier Gonze <gonze@pcpm.ucl.ac.be>]

Dear Lee Geunsik,

I suspect that you have SCF convergence problems with some
perturbations at the additional q points (going
from 4x4x4 to 6x6x6 to 8x8x8). Might be that
nstep 20
is not enough for the additional q points ?!
You might try to grep messages about lack of convergence
in the output file of the 6x6x6 and 8x8x8 grids.

Xavier



Lee Geunsik wrote:
> Dear all,
>  
> I have calculated IFCs of Si for 4x4x4, 6x6x6, 8x8x8 q-mesh.
> Also I drawed phonon band structure.
> The result is strikingly different as I increase q-mesh.
> I attach the band structure file, "test.ps".
> Followings are related input files for abinit, anaddb.
> What's wrong with me?
>  
> Best regards,
> Geunsik.
>  
> ------------------ input file for abinit ------------------
> ndtset 17
>  
> #Ground state
> kptopt1   1
> tolvrs1   1.0d-18
> iscf1     5
> prtden1   1
>  
> #Non-self consistent ground-state, with general q
>    nqpt2  1
>  getwfk2  1
>  getden2  1
>  kptopt2  3
>  tolwfr2  1.0d-18
>    iscf2  -2
> #Response function with general q
>  rfphon3  1
> rfatpol3  1 2
>   rfdir3  1 1 1
>    nqpt3  1
>  getwfk3  1
>  getwfq3  2
>  kptopt3  3
>  tolvrs3  1.0d-8
>    iscf3  5
>  
> #Non-self consistent ground-state, with general q
>    nqpt4  1
>  getwfk4  1
>  getden4  1
>  kptopt4  3
>  tolwfr4  1.0d-18
>    iscf4  -2
> #Response function with general q
>  rfphon5  1
> rfatpol5  1 2
>   rfdir5  1 1 1
>    nqpt5  1
>  getwfk5  1
>  getwfq5  4
>  kptopt5  3
>  tolvrs5  1.0d-8
>    iscf5  5
> .....
> .....
> qpt2                0.00000000E+00  0.00000000E+00  0.00000000E+00
> qpt3                0.00000000E+00  0.00000000E+00  0.00000000E+00
> qpt4                2.50000000E-01  0.00000000E+00  0.00000000E+00
> qpt5                2.50000000E-01  0.00000000E+00  0.00000000E+00
> qpt6                5.00000000E-01  0.00000000E+00  0.00000000E+00
> qpt7                5.00000000E-01  0.00000000E+00  0.00000000E+00
> qpt8                2.50000000E-01  2.50000000E-01  0.00000000E+00
> qpt9                2.50000000E-01  2.50000000E-01  0.00000000E+00
> qpt10                5.00000000E-01  2.50000000E-01  0.00000000E+00
> qpt11                5.00000000E-01  2.50000000E-01  0.00000000E+00
> qpt12               -2.50000000E-01  2.50000000E-01  0.00000000E+00
> qpt13               -2.50000000E-01  2.50000000E-01  0.00000000E+00
> qpt14                5.00000000E-01  5.00000000E-01  0.00000000E+00
> qpt15                5.00000000E-01  5.00000000E-01  0.00000000E+00
> qpt16               -2.50000000E-01  5.00000000E-01  2.50000000E-01
> qpt17               -2.50000000E-01  5.00000000E-01  2.50000000E-01
> #######################################################################
> #Common input variables
>  
> #Definition of the unit cell
> acell  3*10.166         # This is equivalent to   10.18 10.18 10.18
> rprim  0.0  0.5  0.5   # FCC primitive vectors (to be scaled by acell)
>        0.5  0.0  0.5  
>        0.5  0.5  0.0
>  
> #Definition of the atom types
> ntypat 1          # There is only one type of atom
> znucl 14          # The keyword "znucl" refers to the atomic number of the
>                   # possible type(s) of atom. The pseudopotential(s)
>                   # mentioned in the "files" file must correspond
>                   # to the type(s) of atom. Here, the only type is Silicon.
>                         
> #Definition of the atoms
> natom 2           # There are two atoms
> typat 1 1         # They both are of type 1, that is, Silicon.
> xred              # This keyword indicate that the location of the atoms
>                   # will follow, one triplet of number for each atom
>    0.0  0.0  0.0  # Triplet giving the REDUCED coordinate of atom 1.
>    1/4  1/4  1/4  # Triplet giving the REDUCED coordinate of atom 2.
>  
> nband 4
> ixc 2
> #Definition of the planewave basis set
> ecut  10.0         # Maximal kinetic energy cut-off, in Hartree
>  
> #Definition of the k-point grid
> ngkpt   8 8 8
> nshiftk 1
> shiftk 0.5 0.5 0.5
>  
> #Definition of the SCF procedure
> nstep 20          # Maximal number of SCF cycles
> diemac 12.0
>  
>  
> ------------------ input file for anaddb ------------------
> !Flags
>  ifcflag   1     ! Interatomic force constant flag
>  
> !Effective charges
>      asr   1     ! Acoustic Sum Rule. 1 => imposed asymetrically
>  
>  enunit   2
>  
> !Interatomic force constant info
>   dipdip  0      ! Dipole-dipole interaction treatment
>   ifcana  1      ! Analysis of the IFCs
>   ifcout 20      ! Number of IFC's written in the output, per atom
>   natifc  1      ! Number of atoms in the cell for which ifc's are analysed
>    atifc  1      ! List of atoms
>  
> !Wavevector grid number 1 (coarse grid, from DDB)
>   brav    2      ! Bravais Lattice : 1-S.C., 2-F.C., 3-B.C., 4-Hex.)
>   ngqpt   4  4  4   ! Monkhorst-Pack indices
>   nqshft  1         ! number of q-points in repeated basic q-cell
>   q1shft  0.0  0.0  0.0
>  
> !Wavevector list number 1 (Reduced coordinates and normalization factor)
>   nph1l    61      ! number of phonons in list 1
>   qph1l   0.0 0.0 0.0 1  ! Gamma
> 0.075 0.0375 0.0375 1
> 0.150 0.0750 0.0750 1
> 0.225 0.1125 0.1125 1
> 0.300 0.1500 0.1500 1
> 0.375 0.1875 0.1875 1
> 0.450 0.2250 0.2250 1
> 0.525 0.2625 0.2625 1
> 0.600 0.3000 0.3000 1
> 0.675 0.3375 0.3375 1
> 0.625 0.25 0.625 1       ! K
> 0.6000 0.2000 0.6000 1
> 0.5750 0.1500 0.5750 1
> 0.5500 0.1000 0.5500 1
> 0.5250 0.0500 0.5250 1
> 0.5 0.0 0.5 1            ! X
> 0.450 0.0000 0.4500 1
> 0.400 0.0000 0.4000 1
> 0.350 0.0000 0.3500 1
> 0.300 0.0000 0.3000 1
> 0.250 0.0000 0.2500 1
> 0.200 0.0000 0.2000 1
> 0.150 0.0000 0.1500 1
> 0.100 0.0000 0.1000 1
> 0.050 0.0000 0.0500 1
> 0.0 0.0 0.0 1            ! Gamma
> 0.050 0.0500 0.0500 1
> 0.100 0.1000 0.1000 1
> 0.150 0.1500 0.1500 1
> 0.200 0.2000 0.2000 1
> 0.250 0.2500 0.2500 1
> 0.300 0.3000 0.3000 1
> 0.350 0.3500 0.3500 1
> 0.400 0.4000 0.4000 1
> 0.450 0.4500 0.4500 1
> 0.5 0.5 0.5 1            ! L
> 0.500 0.4500 0.5000 1
> 0.500 0.4000 0.5000 1
> 0.500 0.3500 0.5000 1
> 0.500 0.3000 0.5000 1
> 0.500 0.2500 0.5000 1
> 0.500 0.2000 0.5000 1
> 0.500 0.1500 0.5000 1
> 0.500 0.1000 0.5000 1
> 0.500 0.0500 0.5000 1
> 0.5 0.0 0.5 1          ! X
> 0.550 0.0500 0.5000 1
> 0.600 0.1000 0.5000 1
> 0.650 0.1500 0.5000 1
> 0.700 0.2000 0.5000 1
> 0.75 0.25 0.5 1        ! W
> 0.725 0.2750 0.5000 1
> 0.700 0.3000 0.5000 1
> 0.675 0.3250 0.5000 1
> 0.650 0.3500 0.5000 1
> 0.625 0.3750 0.5000 1
> 0.600 0.4000 0.5000 1
> 0.575 0.4250 0.5000 1
> 0.550 0.4500 0.5000 1
> 0.525 0.4750 0.5000 1
> 0.5 0.5 0.5 1          ! L