ABINIT Discussion Forums

Hi every one...
Im doind calculations using LDA ixc=1 with Troullier-Martins pseudopotential , but when i do the run to get band gap for ZnS , the result is not accurate even with other LDA works . i did my best but i couldn't fix this.. could any one tell me why?? and this is input parameters what im using:
# Computation of the band structure.
# First, a SCF density computation, then a non-SCF band structure calculation.

ndtset 2

#Dataset 1 : usual self-consistent calculation
kptopt1 1 # Option for the automatic generation of k points,
# taking into account the symmetry
nshiftk1 4
shiftk1 0.5 0.5 0.5 # These shifts will be the same for all grids
0.5 0.0 0.0
0.0 0.5 0.0
0.0 0.0 0.5
ngkpt1 6 6 6
prtden1 1 # Print the density, for use by dataset 2
toldfe1 1.0d-6 # This value is way too large for most realistic studies of materials

#Dataset 2 : the band structure
iscf2 -2
getden2 -1
kptopt2 -3
nband2 13
ndivk2 10 12 17 # 10, 12 and 17 divisions of the 3 segments, delimited
# by 4 points.
kptbounds2 0.5 0.0 0.0 # L point
0.0 0.0 0.0 # Gamma point
0.0 0.5 0.5 # X point
1.0 1.0 1.0 # Gamma point in another cell.
tolwfr2 1.0d-12
enunit2 1 # Will output the eigenenergies in eV


#Definition of the unit cell
acell 3*10.22152861
rprim 0.0 0.5 0.5
0.5 0.0 0.5
0.5 0.5 0.0

#Definition of the atom types
ntypat 2
znucl 30 16


#Definition of the atoms
natom 2 # There are two atoms
typat 1 2
xred

0.0 0.0 0.0
1/4 1/4 1/4

#Definition of the planewave basis set
ecut 30 # Maximal kinetic energy cut-off, in Hartree

#Definition of the SCF procedure
nstep 80 # Maximal number of SCF cycles
diemac 12.0 # 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.
# Here, we follow the prescription for bulk silicon.

Thank you

Nawzad A.