The ABINIT Users Mailing List ( CLOSED )

[Fabien Bruneval <fabien.bruneval@cea.fr>]

Dear Brian,

The GW code assumes time-reversal symmetry by default and needs a 
regular k-point grid in the full Brillouin Zone.
So if your k-point grid is "too weird", you can run into troubles.
Could you run your calculation again using
shiftk2  0. 0. 0.
for instance?
I hope this will be enough to solve your problem.


Fabien




Brian Hunter wrote:
> Dear Abiniter,
>  
> When I perform GW calculation for  TiO2, I got a strange thing that 
> calculation aborted  at "SCREENING: Calculation of the susceptibility 
> and dielectric matrices" without any error message.  Would you like to 
> help me to have a look at my input file and guide me what happen in my 
> file? Thank you very much.
>  
> Best,
>  
> Brian
>  
> PS,Here is my input file,
> 1) input file
> # Crystalline TiO2
> # Dataset 1: ground state calculation
> # Dataset 2: calculation of the kss file
> # Dataset 3: calculation of the screening (epsilon^-1 matrix for W)
> # Dataset 4: calculation of the Self-Energy matrix elements (GW 
> corrections)
> ndtset      4
> kptopt   1            # Option for the automatic generation of k points
> ngkpt    4  4  4   # Density of k points
> # Dataset1: usual self-consistent ground-state calculation
> # Definition of the k-point grid
> nkpt1    11
> nshiftk1  1
> nband1    16
> shiftk1  0.5 0.5 0.5  # This grid is the most economical
> prtden1  1         # Print out density
>
> # Dataset2: calculation of kss file
> # Definition of k-points
> nkpt2    26             # A set of 19 k-points containing Gamma
> nshiftk2  1
> shiftk2   0.00   0.00   0.75                  
> istwfk2  26*1                    # Option needed for Gamma
> iscf2    -2             # Non self-consistent calculation
> getden2  -1             # Read previous density file
> nband2   32
> nbandkss2 400        # Number of bands 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      150      # Bands to be used in the screening calculation
> ecutwfn3    15.0     # Planewaves to be used to represent the 
> wavefunctions
> ecuteps3    15.0     # Dimension of the screening matrix
> ppmfrq3    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
> getscr4     -1       # Obtain SCR file from previous dataset
> nband4      250      # Bands to be used in the Self-Energy calculation
> ecutwfn4    15.0      # Planewaves to be used to represent the 
> wavefunctions
> ecutsigx4    18.0      # Dimension of the G sum in Sigma_x
> nkptgw4      1                # number of k-point where to calculate 
> the GW correction
> kptgw4                       # k-points
>   0.000    0.000    7/16     # (Gamma)
> bdgw4       16  17           # calculate GW corrections for bands from 
> 4 to 5
>
> # Definition of the unit cell: fcc
> acell  7.1063221588  7.1063221588  17.839952930
> angdeg  90  90  90
> spgroup 141
> brvltt -1
> chkprim 0
> # Definition of the atom types
> ntypat  2         # There is only one type of atom
> znucl 22  8       # The keyword "znucl" refers to the atomic number of 
> the 
>  natrd  2
> # Definition of the atoms
> natom 6           # There are two atoms
> typat  1 2        # They both are of type 1, that is, Silicon.
> xred              # Reduced coordinate of atoms
>       0.00  0.00  0.00
>       0.00  0.00  0.20759974608
> # Definition of the planewave basis set (at convergence 16 Rydberg 8 
> Hartree)
> ecut 22.0          # Maximal kinetic energy cut-off, in Hartree
> # Use only symmorphic operations
> symmorphi 0
> # Definition of the SCF procedure
> nstep   100       # 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.
> tolwfr  1.0d-10  
> # This line added when defaults were changed (v5.3) to keep the 
> previous, old behaviour
>   iscf 5
>  
> 2) output file
> ....
>
>  test on the normalization of the wavefunctions
>  min sum_G |a(n,k,G)| =  0.990435
>  max sum_G |a(n,k,G)| =  0.999922
>  test on the orthogonalization of the wavefunctions
>  min sum_G a(n,k,G)* a(n",k,G) =  0.000000
>  max sum_G a(n,k,G)* a(n",k,G) =  0.005506
>  setmesh: mesh size selected =  24x 24x 24
>  setmesh: total size of FFT array nr =    13824
>  number of q-points found       54
>  find q-points q = k - k1 and translate in first BZ
> 3) log file
>  
> .....
>  
>   221 0.500 0.500-0.313  0.500 0.500-0.687 -0.313-0.687 0.500 
> -0.687-0.313 0.500
>   225-0.250 0.500-0.313  0.500-0.250 0.063 -0.500 0.250 0.313 -0.313 
> 0.063 0.500
>   229 0.250-0.500-0.063  0.063-0.313-0.250  0.313-0.063 0.250 -0.063 
> 0.313-0.500
>   233 0.250-0.500 0.313 -0.500 0.250-0.063  0.500-0.250-0.313  
> 0.313-0.063-0.500
>   237-0.250 0.500 0.063 -0.063 0.313 0.250 -0.313 0.063-0.250  
> 0.063-0.313 0.500
>   241 0.000 0.000-0.063  0.000 0.000 0.063 -0.063 0.063 0.000  
> 0.063-0.063 0.000
>   245-0.250 0.250-0.063  0.250-0.250 0.063 -0.250 0.250 0.063 -0.063 
> 0.063 0.250
>   249 0.250-0.250-0.063  0.063-0.063-0.250  0.063-0.063 0.250 -0.063 
> 0.063-0.250
>   253 0.500 0.500-0.063  0.500 0.500-0.937 -0.063-0.937 0.500 
> -0.937-0.063 0.500
>  
>  timing point number   50
> -cpu time  =       3.17 seconds
> -real time =       3.35 seconds
>  number of q-points found       54
>  find q-points q = k - k1 and translate in first BZ
> 4) the runnig aborted without any warning or error message in log file.