600f50560910210213w3892ac8dh2fa18103eab8fd41@mail.gmail.com"
type="cite">hi 2 all,
I tried to do Gw calculations for my system YVO4. I have some doubts. I
followed the examples tgw1_1 but not getting the results. Neither the
dielectric constant , dielectric constant with local fields is printed
nor the E, E GW gap and Delta GW. I have not used very high convergance
as for starting the work i want to check with low convergance(then
will increase the convergence).
My input file is listed below . Please help.
1) nband1 100 # these 100 are occupied and empty. How can
we know that out of 100 how may are occupied and how many unoccupied ??
2) what is usual value given to nband2 and
nband3 ??
3) bdgw3 41 42 # here
i want to ask, how we will find these number. Since i want the band gap
b/w the top of valance band and bottom of conduction band. is this 41
and 42 represent the top of VB and bottom of CB ??? or we can do
correction b/w any bands ???
ndtset 3
nbandkss1 -1 #
nband1 100 #
#istwfk1 10*1 #
this point is not clears
# Calculation of the screening (epsilon^-1
matrix)
optdriver2 3 # Screening calculation
getkss2 -1 # Obtain KSS file from previous dataset
nband2 115 # Bands to be used in the screening
calculation
ecutwfn2 4.1 # Cut-off energy of the planewave set to
represent the wavefunctions
ecuteps2 5.6 # Cut-off energy of the planewave set to
represent the dielectric matrix
ppmfrq2 16.7
eV # Imaginary frequency where to
calculate the screening
# Calculation of the Self-Energy matrix
elements (GW
corrections)
optdriver3 4 # Self-Energy calculation
getkss3 -2 # Obtain KSS file from dataset 1
getscr3 -1 #
Obtain SCR file from previous dataset
nband3 130 # Bands to be used in the Self-Energy
calculation
ecutwfn3 2.0 # Planewaves to be used to represent the
wavefunctions, use 5
ecutsigx3 2.0 # Dimension of the G sum in Sigma_x, use 6
#
(the dimension in Sigma_c is controlled by npweps)
nkptgw3 1 # number of k-point where to
calculate the GW correction
kptgw3
# k-points
0.000
0.000
0.000
bdgw3 41 42 #
#Definition of the unit cell (YVO4 is tetragonal)
acell 13.451637476
13.451637476 11.885054518
angdeg 90 90 90
chkprim 0
#Definition of the atom types
ntypat 3 #
There r 3 type of atom
znucl 39 23 8
# The keyword "znucl" refers to the atomic number of the
#Definition of the atoms
natom 24
typat 1 1 1 1 2 2 2 2
3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
xred
0.0000
0.0000
0.0000
/
/
0.3030
0.0000 0.0700
# Definition of the k-point grid
kptopt 1
# Option for the automatic
generation of k points,
nkpt 6
ngkpt 2 2 2 # use 4
4 4
nshiftk 1
shiftk
0.0 0.0 0.0
istwfk 24*1
# This is mandatory in all the GW
steps.
# Use only symmorphic operations
symmorphi 1
# Definition of the planewave basis set (at
convergence 16
Rydberg 8 Hartree)
ecut 2.0 # use
10
# Definition of the SCF procedure
nstep 100
# Maximal number of SCF cycles
toldfe 1.0d-1 # 10-7
diemac 12.0
# Although this is not mandatory, it is
worth to
# This line added when defaults were changed
(v5.3) to keep
the previous, old behaviour
iscf 5
