The ABINIT Users Mailing List ( CLOSED )

[Matteo Giantomassi <gmatteo@pcpm.ucl.ac.be>]

On Tue, 26 Jun 2007, snd2mit@yahoo.co.in wrote:

> Is is possible to calculate GW correction using ABINIT 5.3.4 for structures 
> in the supercell like polymers, 1D chains, molecule contained in a large cell 
> etc?
>
> Thanks
>
> - Madan

It's possible to perform such a kind of calculations but
one should take into account that a supercell approach implies periodic 
boundary conditions.
As a consequence one should perform a converge study with respect to the size 
of
supercell along the nonperiodic dimensions in order to be sure that the isolated system is described correctly. 
Unfortunately it has been reported that the GW corrections converge slowly with the size of the unit cell,
and obtaining accurate results might require quite expensive calculations due 
to the large number of G vectors.

A possible solution consists in employing a coulomb cutoff technique to remove 
the spurious interactions between unphysical images along the nonperiodic
dimensions. Unfortunately this approach is not yet implemented in ABINIS.

For more details on this topic you can have a look at:
Phys. Rev. B 73, 205119 (2006)
Phys. Rev. B 73, 233103 (2006)

Best Regards,
Matteo Giantomassi
>