The ABINIT Users Mailing List ( CLOSED )

[yunhee.chang@kriss.re.kr]

Dear Abinit users,

I want to calculate the phonon dispersion curve about Si(001) surface problem.
So I tried to calculate the phonon frequencies at special q points 
leaning on the tutorial trf2_1.in file.
In order to compute a phonon band structure, I tried the IFC(Interatomic 
Force Constant) calculations
leaning on the tutorial trf2_4.in file.
But they give me these error messages.

And I don't know exactly the input parameters about "ifcout", "natifc",
"atifc" even though I read their explanations.
In my case, my system have 24 atoms (20 Si atoms and 4 H atoms),
but I want to know about IFC of 20 Si atoms.
At that time "natifc" is 20, "atifc" is 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 
16 17 18 19 20, isn't it?
I'm not sure.

And I used 'ifcout' is 20, but I don't know this meaning exactly..

Would you give me any comments about calculating IFC ?

Error messages is like below.
=========================================================================
 rdddb9 : read     4 blocks from the input DDB
 symq3 : found symmetry   1 preserves q
 symq3 : found symmetry    1 + TimeReversal preserves q
 symq3 : able to use time-reversal symmetry.
  (except for gamma, not yet able to use time-reversal symmetry)
 symq3 : found symmetry   1 preserves q
 symq3 : found symmetry    1 + TimeReversal preserves q
 symq3 : found symmetry   1 preserves q
 symq3 : found symmetry    1 + TimeReversal preserves q
 symq3 : found symmetry   1 preserves q
 symq3 : found symmetry    1 + TimeReversal preserves q
 Now the whole DDB is in central memory
 gtblk9 : enter gtblk9
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    1   21    1   21 5461
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    1   21    2   21 5551
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    1   21    3   21 5641
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    2   21    1   21 5462
 gtblk9 : COMMENT - 
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    2   21    2   21 5552
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    2   21    3   21 5642
 gtblk9 : COMMENT -
  idir1,ipert1,idir2,ipert2,index=    2   21    3   21 5642
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    3   21    1   21 5463
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    3   21    2   21 5553
 gtblk9 : COMMENT -
  The blok     1 does not match the requirement
  because it lacks the element with
  idir1,ipert1,idir2,ipert2,index=    3   21    3   21 5643
 gtblk9 : COMMENT -
  The blok     2 with gamma(1)= 1,
  does not match the requirement blkgam= 0.
 gtblk9 : COMMENT -
  The blok     3 with gamma(1)= 1,
  does not match the requirement blkgam= 0.
 gtblk9 : COMMENT -
  The blok     4 with gamma(1)= 1,
  does not match the requirement blkgam= 0.
 gtblk9 :
  Unable to find block corresponding to the following specifications :
 Type (rfmeth) =  1
 ider qphon(3)         qphnrm   rfphon rfelfd rfstrs
   1  0.00  0.00  0.00  0.00      1      2      0
   2  0.00  0.00  0.00  0.00      1      2      0
 
================================================================================
 
 Calculation of the interatomic forces
 
-begin at tcpu      0.185  and twall      0.186 sec
 ewald9 : ERROR -
  The distance between two atoms seem to vanish.
  This is not allowed.
  Action : check the input for the atoms number    1 and    2.
 
 leave_new : decision taken to exit ...

==============================================================================


And my input files about IFC calculation is like below.
=============================================================================
Input file for the ifc code. Analysis of the Si001 DDB
 
!Flags
 ifcflag   1     ! Interatomic force constant flag
 
!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  8  1   ! Monkhorst-Pack indices
  nqshft  1         ! number of q-points in repeated basic q-cell
  q1shft  3*0.0
 
!Effective charges
     asr   1     ! Acoustic Sum Rule. 1 => imposed asymetrically
  chneut   1     ! Charge neutrality requirement for effective charges.
 
!Interatomic force constant info
  dipdip  1      ! Dipole-dipole interaction treatment
  ifcana  1      ! Analysis of the IFCs
  ifcout 20      ! Number of IFC's written in the output, per atom
  natifc 20      ! Number of atoms in the cell for which ifc's are analysed
   atifc  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20      ! List of 
atoms

===============================================================================

And the input files about generation of the derivative databases is like 
below.
==============================================================================
# Si(001) surface p(2x1).R : Buckled Si dimer structure
 
   ndtset   6
#Set 1 : ground state self-consistency
 
  getwfk1   0            # Cancel default
  kptopt1   1            # Automatic generation of k points, taking
                         # into account the symmetry
    nqpt1   0            # Cancel default
  tolvrs1   1.0d-18      # SCF stopping criterion (modify default)
  rfphon1   0            # Cancel default
  irdwfk1   1
 
#Q vectors for all datasets
 
#Complete set of symmetry-inequivalent qpt chosen to be commensurate
# with kpt mesh so that only one set of GS wave functions is needed.
#Generated automatically by running GS calculation with kptopt=1,
# nshift=0, shiftk=0 0 0 (to include gamma) and taking output kpt set
# file as qpt set. Set nstep=1 so only one iteration runs.
 
     nqpt   1            # One qpt for each dataset (only 0 or 1 allowed)
                         # This is the default for all datasets and must
                         #  be explicitly turned off for dataset 1.
 
     qpt2   0.00000000E+00  0.00000000E+00  0.00000000E+00   # Gamma point
     qpt3   0.00000000E+00  0.00000000E+00  0.00000000E+00   # Gamma point
     qpt4   5.00000000E-01  0.00000000E+00  0.00000000E+00   # J  point
     qpt5   5.00000000E-01  5.00000000E-01  0.00000000E+00   # K  point
     qpt6   0.00000000E-01  5.00000000E-01  0.00000000E+00   # J' point
 
#Set 2 : Response function calculation of d/dk wave function
 
    iscf2   -3         # Need this non-self-consistent option for d/dk
  kptopt2   2          # Modify default to use time-reversal symmetry
  rfphon2   0          # Cancel default
  rfelfd2   2          # Calculate d/dk wave function only
  tolvrs2   0.0        # Cancel default for d/dk
  tolwfr2   1.0d-22    # Use wave function residual criterion instead
 
"phon.in" 125L, 6172C                                                         
                               1,1           Top
    xcart   5.9039889771E+00 -6.0729939581E-07  2.7204853253E+01
            1.0039419724E+01 -4.7860855073E-08  2.8568093438E+01
            3.8319078991E+00  3.6471293249E+00  2.5815824929E+01
            1.0714995504E+01  3.6471292512E+00  2.5945931209E+01
           -6.0517025514E-02  3.6471295365E+00  2.3501237786E+01
            7.4134326200E+00  3.6471306394E+00  2.2948528028E+01
           -4.0574759347E-03 -1.3695151790E-06  2.0844823466E+01
            7.2718944436E+00 -1.8887092077E-06  2.0429191107E+01
            3.5311323308E+00  1.5819469128E-06  1.8057940784E+01
            1.1026081704E+01 -3.5844043594E-06  1.8065100898E+01
            3.5699606282E+00  3.6471264817E+00  1.5482539097E+01
            1.1003352237E+01  3.6471323846E+00  1.5485711239E+01
           -8.8915116479E-03  3.6471243513E+00  1.2839272152E+01
            7.2875484129E+00  3.6471277774E+00  1.2974430170E+01
           -8.8817325561E-03  3.5407020319E-06  1.0280205027E+01
            7.2871615260E+00  4.9870247514E-07  1.0379176488E+01
            3.6641530994E+00 -3.2658218684E-06  7.7508602314E+00
            1.0908373951E+01 -2.7922012069E-06  7.7491057522E+00
            3.6610601969E+00  3.6471311504E+00  5.2171627558E+00
            1.0912345841E+01  3.6471298511E+00  5.2154365698E+00
            1.4473916786E+00  3.6471301284E+00  3.4697106985E+00
            5.8294009642E+00  3.6471293647E+00  3.4125663575E+00
            8.7451596235E+00  3.6471307904E+00  3.4093530778E+00
            1.3127195983E+01  3.6471314038E+00  3.4695504024E+00
            
#Gives the number of band, explicitely (do not take the default)
    nband   55        
   
#Exchange-correlation functional
                      
      ixc   11            # GGA Perdew-Burke-Ernzerhof GGA functional
                      
#Definition of the planewave basis set
 
     ecut   8.0           # Maximal kinetic energy cut-off, in Hartree
    
#Definition of the k-point grid
    ngkpt   4  8  1
  nshiftk   1              # Use one copy of grid only (default)
   shiftk   0.5 0.5 0.0    # This gives the usual fcc Monkhorst-Pack grid
                                                                              
                               77,5          89%
  nshiftk   1              # Use one copy of grid only (default)
   shiftk   0.5 0.5 0.0    # This gives the usual fcc Monkhorst-Pack grid
 
#Definition of the SCF procedure
     iscf   5          # Self-consistent calculation, using algorithm 5
    nstep   30         # Maximal number of SCF cycles
   diemac  12.0        # Although this is not mandatory, it is worth to
                       # precondition the SCF cycle. The model dielectric
                       # function used as the standard preconditioner
                       # is described in the "dielng" input variable section.
                       # The dielectric constant of AlAs is smaller that the 
one of Si (=12).

=============================================================================

I'm sorry it's quite complicated...

I'm waiting for your comments and help~!

Thank you very much~!

Best regards,
Yunhee Chang