The ABINIT Users Mailing List ( CLOSED )

[Aldo Humberto Romero <ahromero@bethe.fis.puc.cl>]

Dear Abinit users

Aftger a good cell parameter optimization I have tried to
calcuylate Phonons at Gamma point of my YVO4 system but after
chaging several of the parameters I do not get convergence.
The program complains that:

 chkph3 : WARNING -
  The dynamical matrix was incomplete : phonon frequencies may be wrong
...

The phonon frequencies I am getting are really off
from the experiment... can somebody give me a hint?. I am including
the input and output file.

Thanks in advance

-aldo.

-------------------------------------------------------------------------
Dr. Aldo Humberto Romero            
IPICyT
Advanced Materials Department
Av. Venustiano Carranza 2425-A,
78270 San Luis Potosi, SLP, Mexico

email:  aldo@ipicyt.edu.mx
Phone:  (52)-444-8-33-54-11
Fax:    (52)-444-8-33-54-12
http://www.ipicyt.edu.mx/
# Crystalline ZnS in Zincblende structure: computation of the total energy
# Phonons at Gamma point points at 0 GPa
 ndtset 3

     rfasr  2
#Ground state calculation
  kptopt1   1             # Automatic generation of k points, taking
                          # into account the symmetry
  tolvrs1   1.0d-18       # SCF stopping criterion
    iscf1   5             # Self-consistent calculation, using algorithm 5
#Response Function calculation : d/dk
  rfelfd2   2             # Activate the calculation of the d/dk perturbation
   rfdir2   1 0 0         # Need to consider the perturbation in the 
x-direction only

    nqpt2   1
     qpt2   0.0 0.0 0.0   # This is a calculation at the Gamma point

  getwfk2   -1            # Uses as input the output wf of the previous 
dataset

  kptopt2   2             # Automatic generation of k points,
                          # using only the time-reversal symmetry to decrease
                          # the size of the k point set.

    iscf2  -3             # The d/dk perturbation must be treated
                          # in a non-self-consistent way
  tolwfr2   1.0d-22       # Must use tolwfr for non-self-consistent 
calculations

#Response Function calculation : electric field perturbation and phonons
  rfphon3   1             # Activate the calculation of the atomic 
dispacement perturbations
 rfatpol3   1 12           # All the atoms will be displaced

  rfelfd3   3             # Activate the calculation of the electric field 
perturbation
   rfdir3   1 0 0         # Need to consider the perturbation in the 
x-direction only

    nqpt3   1
     qpt3   0.0 0.0 0.0   # This is a calculation at the Gamma point

  getwfk3  -2             # Uses as input wfs the output wfs of the dataset 1
  getddk3  -1             # Uses as input ddk wfs the output of the dataset 2

  kptopt3   2             # Automatic generation of k points,
                          # using only the time-reversal symmetry to decrease
                          # the size of the k point set.
  tolvrs3   1.0d-8
    iscf3   5             # Self-consistent calculation, using algorithm 5

#######################################################################

#Definition of the k-point grids

ecut   50
nband  80
ngkpt  5 5 3
nshiftk 1
ixc     11
shiftk  0.0 0.0 0.5
#getwfk 1         # This is to speed up the calculation  by restarting
                  # from previous wavefunctions  transferred from the old 
                  # to the new k-points.
# prtvol -1          # stop in abinis (main program), before call gstate.
# brvltt -1          # important to reduce the conventional cell to primitive,
                   # and allow the recognition of space group
acell
    1.0051865394E+00  1.0051865394E+00  1.0051865394E+00 
rprim
     13.451076    0.00000000000000    0.00000000000000
     0.00000000000000   13.451076     0.00000000000000
     6.725538           6.725538    5.942245      
# the coordinates of the atoms:
xred
  -0.12500000 -0.37500000  0.25000000
   0.12500000  0.37500000 -0.25000000
  -0.37500000 -0.12500000 -0.25000000
   0.37500000  0.12500000  0.25000000
  -0.19530000 -0.12920000  0.39060000
  -0.19530000  0.23860000  0.39060000
  -0.26140000  0.30470000 -0.10940000
   0.37080000  0.30470000 -0.10940000
   0.19530000  0.12920000 -0.39060000
   0.19530000 -0.23860000 -0.39060000
   0.26140000 -0.30470000  0.10940000
  -0.37080000 -0.30470000  0.10940000
natom  12
nsppol 1
zatnum 39.00  23.00  8.000
# amu    91.2200  28.0860  15.9994 Masses for MD in ZrSiO4
ntypat  3
typat   2*1 2*2 8*3

#Definition of the SCF procedure
nstep 2000          # Maximal number of SCF cycles
diemac 100.       # 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. 
diemac=(e_0_long+2*e_0_trans)/3

Attachment: logout.out_gamma2000
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