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[Pascal Boulet <pascal.boulet@univ-provence.fr>]

Dear Abinit users,

I have a problem to compute phonon bands using the reponse function 
formalism. I try to follow the tutorial for that but Abinit (v5.4.4) 
stops when starting the calculation at q-points other than the gamma one.

First, here's my input file (which is largely inspired from the tutorial):
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
ndtset 15
# DS 1 : ground state self-consistency
 getwfk1   0            # Cancel default
 kptopt1   1            # Automatic generation of k points
   nqpt1   0            # Cancel default
 tolvrs1   1.0d-18      # SCF stopping criterion (modify default)
 rfphon1   0            # Cancel default

# DS 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-18    # Use wave function residual criterion instead

# DS 3 : Response function calculation of Q=0 phonons and electric field 
pert.
 getddk3   2          # d/dk wave functions from last dataset
 kptopt3   2          # Modify default to use time-reversal symmetry
 rfelfd3   3          # Electric-field perturbation response only

# DS 4-15 : Finite-wave-vector phonon calculations
  getwfk   1          # Use GS wave functions from dataset 1
  kptopt   3          # Need full k-point set for finite-Q response
  rfphon   1          # Do phonon response
 rfatpol   1 3        # Treat displacements of all atoms
   rfdir   1 1 1      # Do all directions (symmetry will be used)
  tolvrs   1.0d-12    # This default is active for sets 3-15

# q-points
  nqpt   1
  qpt2   0.0000  0.0000  0.0000
  qpt3   0.0000  0.0000  0.0000
  qpt4   1/12    0.0000  0.0000
  qpt5   1/6     0.0000  0.0000
  qpt6   1/4     0.0000  0.0000
  qpt7   1/3     0.0000  0.0000
  qpt8   5/12    0.0000  0.0000
  qpt9   1/2     0.0000  0.0000
  qpt10  1/12    1/12    0.0000
  qpt11  1/6     1/12    0.0000
  qpt12  1/4     1/12    0.0000
  qpt13  1/3     1/12    0.0000
  qpt14  5/12    1/12    0.0000
  qpt15  1/2     1/12    0.0000 

# common variables
# cell definition
 acell  3*12.059281889
 rprim  0.0  0.5  0.5 
        0.5  0.0  0.5 
        0.5  0.5  0.0  

# k-points
   ngkpt   3*4           # number of k points of Monkhorst-Pack grids
 nshiftk   4
  shiftk   0.5 0.5 0.5
           0.5 0.0 0.0
           0.0 0.5 0.0
           0.0 0.0 0.5

# dft procedure and accuracy
   ixc 11
 nstep 80
  ecut 120. Ry

# spin polarization and bands occupation
   nband   4
  nsppol   1
 nspinor   1
  nspden   1

# dielectric (for semiconductors)
 diemac 9.0

# atom and symmetry
  natom  3
 ntypat  2
  typat  1 2 2
  znucl  ... ...
   xred
  0.     0.     0.
  0.25   0.25   0.25
  0.75   0.75   0.75
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

The q-points where generated with the following input file:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
  kptopt   1
  ngkpt3   3*12          # number of k points of Monkhorst-Pack grids
 nshiftk   1
  shiftk   0.0 0.0 0.0
  prtvol   1
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

I get 72 q-points. For CPU-time limitation reasons I start computing 
phonons for the first 12 q-points only (first input file).

Now the error message I get is the following:
The file k444.o_DS1_WFK cannot be used to start the
present calculation. It was asked that the wavefunctions be accurate, but
at least one of the k points could not be generated from a symmetrical one.
dksqmax=    1.432570E-04
Action: check your wf file and k point input variables
(e.g. kptopt or shiftk might be wrong in the present dataset or the 
preparatory one.


The "usual" grid of point for FCC cells is shifted:
 nshiftk   4
  shiftk   0.5 0.5 0.5     0.5 0.0 0.0     0.0 0.5 0.0      0.0 0.0 0.5
whereas the q-points where generated with:
  nshiftk   1
  shiftk   0.0  0.0  0.0

Is this the problem?


Thank you for your hep
Pascal


--
Dr. Pascal Boulet, Computational Chemist
University Aix-Marseille I
Laboratoire Chimie Provence, UMR6264
Centre Saint-Jerome, Bat. MADIREL
F-13397 MARSEILLE Cedex 20, France
Tel. +33 (0) 491 63 71 17 Fax. +33 (0) 491 63 71 11
courriel: pascal.boulet@univ-provence.fr
http://www.lc-provence.fr
http://allos.up.univ-mrs.fr/boulet