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[thanusit@kku.ac.th]

Dear all Abinit members

I'm trying to prepare the KSS file for GW calculation of Si-band, with the 
parallelized abinit version 5.4.3. The input for KSS generation is as below:

--------------------------
# Dataset2: calculation of kss file
nkpt2    19             
nshiftk2  4
shiftk2  0.0 0.0 0.0   
         0.0 0.5 0.5
         0.5 0.0 0.5
         0.5 0.5 0.0
istwfk2  19*1           
iscf2    -2            
getden2  -1           
nband2   10
nbandkss2 100       
kssform2  3
tolwfr2  1.0d-10
--------------------------------

The calculation was completed. I found that the number of bands stored in the 
kss file was 10 instead of 100 as specified by nbandkss2. The part of the 
output looks like this:

======================================================================
 Calculating and writing out Kohn-Sham electronic Structure file
 Using conjugate gradient wavefunctions and energies (kssform=3)
 number of Gamma centered plane waves    507
 number of Gamma centered shells     41
 number of bands     10
 maximum angular momentum components      3
 Conjugate gradient eigenvalues
   k    eigenvalues [Hartree]
   1     -0.2183  0.1626  0.1824  0.1824  0.2841  0.3474  0.3474  0.3664  
0.4523
          0.5137
 ......

However, as I set the kssform2  to 1, the number of bands stored in the kss 
file was 100 as expected. My points are:

1. Is this the usual result when we set the kssform = 3?
2. In the convergence study of GW corrections with respected to nband, we 
need to vary the nband to some value beyond 10. Suppose the number of bands 
stored in the KSS file is 10, can we still do so (set nband above 10) without 
getting incorrect results? 

Besr regards,
Thanusit Burinprakhon