ABINIT Discussion Forums

Dear All,
I have run the lesson respons function 1,and the calculation was completed,but dielectric constant have not printed and i had the following warning:the dynamical matrix was incomplet:phonon frequencies may be wrong..
................
computation of the response to homogeneous
# electric field and atomic displacements, at q=0
#

ndtset 3

#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
# This is rather specific, due to the high symmetry of the AlAs crystal
# In general, just use rfdir 1 1 1
# In the present version of ABINIT (v4.6), symmetry cannot be used
# to reduce the number of ddk perturbations

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
# Here, the value of tolwfr is very low.

#Response Function calculation : electric field perturbation and phonons
rfphon3 1 # Activate the calculation of the atomic dispacement perturbations
rfatpol3 1 2 # All the atoms will be displaced
rfelfd3 3 # Activate the calculation of the electric field perturbation
rfdir3 1 1 1 # All directions are selected. However, symmetries will be used to decrease
# the number of perturbations, so only the x electric field is needed
# (and this explains why in the second dataset, rfdir was set to 1 0 0).

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


#######################################################################
#Common input variables

#Definition of the unit cell
acell 10.938662993 10.938662993 10.938662993
angdeg 3*56.654541304

#Definition of the atom types
ntypat 2
znucl 49 8
natom 10
spgroup 167 # There are two atoms

spgaxor 2
typat 1 1 1 1 2 2 2 2 2 2 # They both are of type 1, that is, Silicon.
xred # Reduced coordinate of atoms
0.35770000 0.35770000 0.35770000
...
...
...
...

#Gives the number of band, explicitely (do not take the default)
nband 24 # For an insulator (if described correctly as an insulator
# by DFT), there is no need to include conduction bands
# in response-function calculations

#Exchange-correlation functional
ixc 1 # LDA Teter Pade parametrization

#Definition of the planewave basis set
ecut 21 # Maximal kinetic energy cut-off, in Hartree

#Definition of the k-point grid
nshiftk 1
shiftk 0.5 0.5 0.5
ngkpt 4 4 4 ! This is much too low : should be at least 24x24x24


#Definition of the SCF procedure
nstep 1500 # Maximal number of SCF cycles
diemac 10 # 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).
...............................
Can any one guid me?
asadi.

Can you post your output file? And did you grep your output for "Dielectric" (note upper-case D)?