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[GaoTao <gaotaoscu@hotmail.com>]

Hi Matthieu,
 
Thanks four your response. Here enclosed is my input files and output files. It is about 3.5MB.
 
Regards,
 
Tao
 
> Date: Tue, 24 Mar 2009 14:29:28 +0100
> From: matthieu.jean.verstraete@gmail.com
> To: forum@abinit.org
> Subject: Re: [abinit-forum] No LO-TO splitting in my CaF2 calculation
>
> Hello Tao,
>
> this is indeed very strange, and you should definitely have an LO-TO
> splitting. Do you have the convergence information for the DDK run?
> Could it be that it did not converge? The rest of your input looks
> quite correct. You might send a tarball of all the outputs, if they
> are not too heavy.
>
> Cheers
>
> Matthieu
>
> On Mon, Mar 23, 2009 at 6:05 PM, <gaotaoscu@hotmail.com> wrote:
> > Dear All,
> >
> > When I try to reproduce the TO-LO splitting for CaF2 (original paper: PHYSICAL
> > REVIEW B vol68, 195123,2003),I got no LO-TO splitting in my calculation.
> > According to the experiments and the theor etical calculation, there should have
> > a TO-LO splitting in Gamma point for CaF2, but my input file is not able to let
> > these kind of slitting. my version is abinit-5.4.4p, and pseudopotential is
> > '20ca.pspnc' and '9f.pspnc'. Below is my setting for the DDB and phonon parts,
> > and the related output, any comments or suggestion is appreciated.
> >
> > 1,Generation of the derivative databases,
> > # Crystalline CaF2 : computation of the phonon spectrum
> >
> >   ndtset   10
> >  getwfk1   0            # Cancel default
> >  kptopt1   1            # Automatic generation of k points, taking
> >                         # into account the symmetry
> >    nqpt1   0         &n bsp;  # Cancel default
> >  tolvrs1   1.0d-18      # SCF stopping criterion (modify default)
> >  rfphon1   0            # Cancel default
> >
> > #Q vectors for all datasets
> >
> >     nqpt   1            # One qpt for each dataset (only 0 or 1 allowed)
> >
> >     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   5.00000000E-01  0.00000000E+00  0.00000000E+00
> >     qpt6   2.50000000E-01  2.50000000E-01  0.00000000E+00
> >     qpt7   5.00000000E-01  2.50000000E-01  0.00000000E+00
> >     qpt8  -2.50000 000E-01  2.50000000E-01  0.00000000E+00
> >     qpt9   5.00000000E-01  5.00000000E-01  0.00000000E+00
> >     qpt10 -2.50000000E-01  5.00000000E-01  2.50000000E-01
> >
> > #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
> >
> > #Set 3 : Response function calculation of Q=0 phonons and electric field p ert.
> >
> >  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
> >
> > #Sets 4-10 : Finite-wave-vector phonon calculations (defaults for all datasets)
> >
> >   getwfk   1          # Use GS wave functions from dataset1
> >   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 wi ll be used)
> >   tolvrs   1.0d-8     # This default is active for sets 3-10
> >
> > #Common input variables
> > #Definition of the unit cell
> >    acell   3*10.3232         # This is equivalent to   10.61 10.61 10.61
> >    rprim   0.0  0.5  0.5   # In lessons 1 and 2, these primitive vectors
> >            0.5  0.0  0.5   # (to be scaled by acell) were 1 0 0  0 1 0  0 0 1
> >            0.5  0.5  0.0   # that is, the default.
> >
> > #Definition of the atom types
> >   ntypat   2         # There are two types of atom
> >    znucl   20 9     # The keyword "znucl" refers to the atomic number of the
> >     &n bsp;                # possibl e type(s) of atom. The pseudopotential(s)
> >                      # mentioned in the "files" file must correspond
> >                      # to the type(s) of atom. Here, type 1 is the Aluminum,
> >                      # type 2 is the Arsenic.
> >
> > #Definition of the atoms
> >    natom   3         # There are two atoms
> >    typat   1 2 2       # The first is of type 1 (Al), the second is of type 2
> > (As).
> >    xred                      # will follow, one triplet of number for each
> > atom
> >         0.0  0.0  0.0      # Triplet givi ng the REDUCED coordinate of atom 1.
> >         1/4  1/4  1/4      # Triplet giving the REDUCED coordinate of atom 2.
> >         3/4  3/4  3/4               # Note the use of fractions (remember the
> > limited
> >
> > #Gives the number of band, explicitely (do not take the default)
> >    nband   11
> >    occopt  3
> > #Exchange-correlation functional
> >
> >      ixc   1             # LDA Teter Pade parametrization
> >
> > #Definition of the planewave basis set
> >
> >     ecut   26.0           # Maximal kinetic energy cut-off, in Hartree
> >
> > #Definition of the k-point grid
> >     ;ngkpt   4  4  4
> >  nshiftk   4 & nbsp;            # Use one copy of grid only (default)
> >   shiftk   0.0 0.0 0.5    # This gives the usual fcc Monkhorst-Pack grid
> >            0.0 0.5 0.0
> >            0.5 0.0 0.0
> >            0.5 0.5 0.5
> >
> > #Definition of the SCF procedure
> >    iscf     7        # Self-consistent calculation, using algorithm 5
> >    nstep   1500      # Maximal number of SCF cycles
> >    diemac   9.0      # Although this is not mandatory, it is worth to
> >                      # precondition the SCF cycle. The model dielectric
> >
> > XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXX
> > XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> > 2,computation of phonon band structures
> >
> > !Input file for the ifc code. Analysis of the CaF2 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  4  4   ! 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
> >
> > !Phonon band structure output for band2eps - See note near end for
> > ! dealing with gamma LO-TO splitting issue.
> >   eivec  4
> >
> > !Wavevector list number 1 (Reduced coordinates and normalization factor)
> >
> >  nph1l    80      ! number of phonons in list 1
> >
> >  qph1l       0.00000000E+00  0.00000000E+00  0.00000000E+00  1.0
> >              5.00000000E-02  2.50000000E-02  2.50000000E-02  1.0
> >              1.00000000E-01  5.00000000E-02  5.00000000E-02  1.0
> >                  .........................................
> >              5.00000000E-01  4.50000000E-01  5.50000000E-01  1.0
> >              5.00000000E-01  4.75000000E-01  5.25000000E-01  1.0
> >              5.00000000E-01  5.00000000E-01  5.00000000E-01  1.0
> >
> > !Wavevector list number 2 (Cartesian directions for non-analytic gamma phonons)
> >
> > !The output for this calculation must be cut-and-pasted into the
> > ! t59_out.freq file to be used as band2eps input to get proper LO-TO
> > ! splitting at gamma.  Note that gamma occurrs twice.
> >
> >  nph2l    1       ! number of directions in list 2
> >
> >  qph2l   1.0  0.0  0.0    0.0
> > XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> &g t; XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> > 3, output of LO-TO splitting.
> >     ........................................................
> >  Treat the second list of vectors
> > -begin at tcpu      0.470  and twall      0.957 sec
> >  Phonon at Gamma, with non-analyticity in the
> >  direction (cartesian coordinates)  1.00000  0.00000  0.00000
> >  Phonon energies in Hartree :
> >   0.000000E+00  0.000000E+00  0.000000E+00  1.634493E-03  1.634494E-03
> >   1.634498E-03  1.962988E-03  1.962988E-03  1.962990E-03
> >  Phonon frequencies in cm-1    :
> > -  0.000000E+00  0.000000E+00  0.000000E+00  3.587298E+02  3.587300E+02
> > -  3.587309E+02  4.308260E+02  4.308260E+02  4.308265E+02
> > +Total cpu time      0. 470  and wall time      0.959 sec
> >  anaddb : the run completed succesfully.
> >
> > Regards,
> >
> > Tao
> >
>
>
>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Dr. Matthieu Verstraete
>
> European Theoretical Spectroscopy Facility (ETSF)
> Dpto. Fisica de Materiales,
> U. del Pais Vasco,
> Centro Joxe Mari Korta, Av. de Tolosa, 72, Phone: +34-943018393
> E-20018 Donostia-San Sebastian, Spain Fax  : +34-943018390
>
> Mail : matthieu.jean.verstraete@gmail.com
> http://www-users.york.ac.uk/~mjv500
>

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