The ABINIT Users Mailing List ( CLOSED )

[Riad Shaltaf <shaltaf@pcpm.ucl.ac.be>]

Dear Salvador,

The 'inclvkb' is meant to include the commutators [Vnl,iqr] in the
calculation of the wings of the polarizability in the limit q=0.
see Appendix B of Olevano et al , PRB 60,14224 (1999).
This shall be important in case you are doing the calculation using a
small number of k points. This extra term is time consuming, and it can
be neglected in case you are using a denser k point grid.
What error can be produced neglecting this term, for case of Si bulk
(4x4x4 k point grid), switching the calculation of this term off leads
to an error~ 0.01 eV. In your case it is worth to check it, and
according to the amount of error, you will be able to judge on the
accuracy of your results.
You will not be able to calculate the GW corrections for a k point,
which is absent from the KSS grid, the code needs the LDA/GGA
wavefunctions and energies for that point to proceed in (optdriver 4).
But you can be able to estimate GW corrections for k points not included
in KSS grid by interpolating the results for other k points. 

I hope this might help..
-- 
Riad Shaltaf                       UCL/SE/FSA/MAPR/PCPM
Tel: +32 (0)10 47 28 50            Bâtiment Boltzmann, a+1
Fax: +32 (0)10 47 34 52            1 place Croix du Sud
Mel: shaltaf@pcpm.ucl.ac.be        1348 Louvain-la-Neuve (Belgique)