The ABINIT Users Mailing List ( CLOSED )

["D. R. Hamann" <drh@bell-labs.com>]

Matthew,

The implementation of nonlocal psp's in Abinit is undocumented as far as 
I know except for a thick sheath of notes by Doug Allan in the Abinit 
archives.   Section III E of my recent paper,
http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRBMDO000071000003035117000001&idtype=cvips&gifs=yes 
<http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PRBMDO000071000003035117000001&idtype=cvips&gifs=yes>
will give you a general idea of how they are handled.

I have run cross-comparisons between Abinit and several of my own codes, 
inputting the same psp's as tabulated real-space radial functions to 
each, and get essentially identical results.

Don

m.foulkes@imperial.ac.uk wrote:

> As a test, one of my research students took a self-consistent Si potential 
> from Abinit and fed it into a program of his own, which carries out a single 
> non-selfconsistent solution of the Kohn-Sham Hamiltonian to find the electron 
> density. When he disabled the non-locality of the pseudopotential (in Abinit 
> and his own program) his density agreed exactly with the density calculated 
> by Abinit; but when he used the full non-local pseudopotential in both 
> programs there were significant differences.
>
> We cannot explain this discrepancy, especially since the non-local 
> pseudopotential form factors we use were written out from inside Abinit 
> itself. Our best guess is that Abinit's way of implementing non-local 
> (Kleinman-Bylander) pseudopotentials is not as we had been assuming. We have 
> already looked at (parts of) the source code and scanned the literature, but 
> remain unsure.
>
> Are there any papers or other documentation in which the details of Abinit's 
> implementation of KB pseudopotentials are explained? If not, does Abinit do 
> anything unusual that might have caught us out?
>  


--
D. R. Hamann                            Phone: 908-582-4454
Director, Theoretical Materials         Fax:   908-582-4868
 Physics Research (retired)             email: drh@physics.bell-labs.com
Bell Laboratories 
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