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[GaoTao <gaotaoscu@hotmail.com>]

Thanks for your suggestion. I will try this option, and hope it works.
Tao
 
> Date: Tue, 31 Mar 2009 00:02:02 +0200
> From: matthieu.jean.verstraete@gmail.com
> To: forum@abinit.org
> Subject: Re: [abinit-forum] No LO-TO splitting in my CaF2 calculation
>
> I can't see much wrong, apart possibly from occopt, which you have set
> to 3 (metallic). Probably for this reason the ddk has not been
> included in the ddb file: check for ipert=4 idir=1,2,3.
>
> Try with an insulator value for occopt.
>
> Matthieu
>
> On Tue, Mar 24, 2009 at 3:29 PM, matthieu verstraete
> <matthieu.jean.verstraete@gmail.com> wrote:
> > 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 theoretical 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 data bases,
> >> # Crystalline CaF2 : computation of the phono n spectrum
> >>
> >>   ndtset   10
> >>  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
> >>
> >> #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  -2.50000000E-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 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
> >>
> >> #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 will 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 &n bsp;       # 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
> >>                      # possible type(s) of atom. The pseudopotential(s)
> >>                      # mentioned in the "files" file must correspond
> >>     &nbs p;                # 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 giving 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              # 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
> >>
> >> XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> >> XXXXXXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> >> 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 cons tant 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
> >>                  .........................................
> >&g t;              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
> >> XXXXXXX XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
> >> 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 & nbsp;3.587298E+02  3.587300E+02
> >> -  3.58730 9E+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
> >
>
> < BR>>
> --
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 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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