The ABINIT Users Mailing List ( CLOSED )

[Gian-Marco Rignanese <rignanese@pcpm.ucl.ac.be>]

Hi,

> Hello all,
> 
> I'm trying to compute the band structure of a crystal with La using the
> GWA. The problem is that it seems impossible to use the HGH
> pseudopotential for La (in version 4.4.3) as one cannot use
> pseudopotentials with more than one projector per angular momentum
> channel.

To be more precise, it is not possible to use pseudopotentials with more than 
one projector per angular 
momentum with "kssform" set to "1". In this case, the eigenvalues and 
eigenfunctions are recalculated 
based on the hamiltonian (either by full diagonalisation or iterative 
diagonalisation). But, if you rely on 
the eigenvalues and eigenfunctions that have already been calculated (with a 
given accuracy defined by 
"tolvrs" or "tolwfr"), you can use "kssform 3" that works with any 
pseudopotential. The price that you 
have to pay is that you need to include all the bands that you need in the 
ground state calculation 
(nband>=nbandkss). Typically, you can run a self-consistent calculation (with 
the usual number of 
bands) to get the density. Then, run a non-self-consistent calculation to 
compute all the bands that 
you need.

It is actually not clear if the second method is slower than performing the 
full diagonalization of the 
Hamiltonian.

>Is it the same for the latest version of Abinit?
Yes... and it will remain so unless someone volunteers to implement that!!!


Best regards,

Gian-Marco.

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