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[Valerio Olevano <valerio.olevano@polytechnique.fr>]

Dear Denis,
your mesh seems good. it is that one used in the tutorial
which works. so it is strange that the tutorial
is not working in your case.
check if in dataset 3, the screening calculation
the q-point 0 -0.250 0
(or a symmetry equivalent) is taken into account.
regards V.O

On Thu, 2005-01-13 at 16:13, denis.rideau@st.com wrote:
> I do not succeed to compute the total Band structure with ABINIT. One can 
> not obtain the GW correction at a given kpoint.
> 
> I was said that it is possible to get electronic energies on a mesh of k 
> points and to plot the quasi-particle correction
> to the LDA value as a function of the LDA energy, in the spirit of
> Fig. 1 of Phys. Rev. B34, 5390 (1986),
> then make a linear interpolation for each group of points
> corresponding to one band, and use that interpolation to correct
> the LDA band structure at every point.
> 
> When I try to do so I obtain: 
> 
>  calculating <nk|sigma|nk>
>  k =    0.000   0.000   0.000
>  bands n = from   1 to   8
> 
>  **error gw 103: q = k - k1 + g0 not found.
>  ikbz  =  193 0.0E+0 0.0E+0 0.0E+0
>  ik1bz =  257 0.0E+0 0.2 0.0E+0
>  kmk1  =  0.0E+0 -0.2 0.0E+0
> STOP: q = k - k1 + g0 not found
> 
> 
> 
> ===>My question is: What is the most efficient way to obtain a mesh of k 
> points and how to do it?
> 
> I am very appreciated for any help!
> 
> Denis Rideau
> 
> 
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%5
> PS: The .in used was for instance:
> 
> # Crystalline silicon
> # Calculation of the GW correction to the direct band gap in Gamma
> # Dataset 1: ground state calculation 
> # Dataset 2: calulcation of the kss file for only Gamma point
> # Dataset 3: calculation of the screening (epsilon^-1 matrix for W)
> # Dataset 4: calculation of the Self-Energy matrix elements (GW corrections)
> 
> # Definition of the unit cell: fcc
> acell  3*10.217        # This is equivalent to   10.217 10.217 10.217
> rprim  0.0  0.5  0.5   # FCC primitive vectors (to be scaled by acell)
>        0.5  0.0  0.5   
>        0.5  0.5  0.0
> 
> # Definition of the atom types
> ntypat  1         # There is only one type of atom
> znucl 14          # 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
>                   # to the type(s) of atom. Here, the only type is Silicon.
>                          
> # Definition of the atoms
> natom 2           # There are two atoms
> typat  1 1        # They both are of type 1, that is, Silicon.
> xred              # Reduced coordinate of atoms
>       0.0  0.0  0.0
>       0.25 0.25 0.25
> 
> # Definition of the planewave basis set (at convergence 16 Rydberg 8 
> Hartree)
> ecut 8.0          # Maximal kinetic energy cut-off, in Hartree
> 
> # Definition of the SCF procedure
> nstep   10        # 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.
> 
> ndtset      4
> 
> # Dataset1: usual self-consistent ground-state calculation
> kptopt1  0 # K-points will be provided
> nkpt1    19 # 
> kpt1
>       -0.375     0.125     -0.250
>       -0.500     0.125     -0.375
>       -0.125     0.375      0.000
>       -0.250     0.375     -0.125
>       -0.125     0.125      0.000
>       -0.250     0.125     -0.125
>       -0.125     0.250     -0.125
>       -0.375     0.250     -0.125
>       -0.375     0.250     -0.375
>       -0.125     0.000     -0.125
>       -0.375     0.000     -0.375
>        0.000     0.000      0.000
>       -0.250     0.000     -0.250
>       -0.500     0.000     -0.500
>        0.000     0.250      0.000
>       -0.250     0.250      0.000
>       -0.250     0.250     -0.250
>       -0.500     0.250     -0.250
>        0.000     0.500      0.000
> 
> istwfk1  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  # 
> # Definition of the SCF procedure
> toldfe1  1.0d-6    # Will stop when this tolerance is achieved on total 
> energy
> prtden1  1         # Print out density
> 
> # Dataset2: calculation of kss file
> # Definition of k-points
> kptopt2  0 # K-points will be provided
> nkpt2    19 # A set of 19 k-points containing Gamma
> kpt2
>       -0.375     0.125     -0.250
>       -0.500     0.125     -0.375
>       -0.125     0.375      0.000
>       -0.250     0.375     -0.125
>       -0.125     0.125      0.000
>       -0.250     0.125     -0.125
>       -0.125     0.250     -0.125
>       -0.375     0.250     -0.125
>       -0.375     0.250     -0.375
>       -0.125     0.000     -0.125
>       -0.375     0.000     -0.375
>        0.000     0.000      0.000
>       -0.250     0.000     -0.250
>       -0.500     0.000     -0.500
>        0.000     0.250      0.000
>       -0.250     0.250      0.000
>       -0.250     0.250     -0.250
>       -0.500     0.250     -0.250
>        0.000     0.500      0.000
> 
> istwfk2  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1  # 
> # Definition of the SCF procedure
> iscf2    -2             # Non self-consistent calculation
> getden2  -1             # Read previous density file
> tolwfr2  1.0d-1         # It's not important, as later there is a diago
> nband2   9
> # Definition of parameters for the calculation of the kss file
> nbndsto2 100        # Number of bands to store in KSS file
> ncomsto2 169        # Number of plane waves to store in KSS file
> 
> # Dataset3: Calculation of the screening (epsilon^-1 matrix)
> optdriver3  3        # Screening calculation
> getkss3     -1       # Obtain KSS file from previous dataset
> nband3      25       # Bands to be used in the screening calculation
> npwwfn3     137       # Planewaves to be used to represent the wavefunctions
> npweps3     169      # Dimension of the screening matrix
> plasfrq3    16.7 eV  # Imaginary frequency where to calculate the screening
> 
> # Dataset4: Calculation of the Self-Energy matrix elements (GW corrections)
> optdriver4  4        # Self-Energy calculation
> getkss4     -2       # Obtain KSS file from dataset 1
> geteps4     -1       # Obtain EM1 file from previous dataset
> nband4      100      # Bands to be used in the Self-Energy calculation
> npwwfn4     137      # Planewaves to be used to represent the wavefunctions
> npwmat4     169      # Dimension of the G sum in Sigma_x
>                      # (the dimension in Sigma_c is controlled by npweps)
> ngwpt4      19                # number of k-point where to calculate the GW 
> correction
> kptgw4                       # k-points
>       -0.375     0.125     -0.250
>       -0.500     0.125     -0.375
>       -0.125     0.375      0.000
>       -0.250     0.375     -0.125
>       -0.125     0.125      0.000
>       -0.250     0.125     -0.125
>       -0.125     0.250     -0.125
>       -0.375     0.250     -0.125
>       -0.375     0.250     -0.375
>       -0.125     0.000     -0.125
>       -0.375     0.000     -0.375
>        0.000     0.000      0.000
>       -0.250     0.000     -0.250
>       -0.500     0.000     -0.500
>        0.000     0.250      0.000
>       -0.250     0.250      0.000
>       -0.250     0.250     -0.250
>       -0.500     0.250     -0.250
>        0.000     0.500      0.000
> bdgw4       1  8             # calculate GW corrections 
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
>        1  8      
> zcut4       0.1 eV           # parameter to avoid poles
> 
> 
> 
> 
> 
> 
>