[Pw_forum] external potential and partial wavefunctions

Zhiping Yin yinzping at gmail.com
Sat Mar 24 01:14:51 CET 2007

Dear Guido,

Thanks very much for your kindly reply!
The external potential should contain both the local part (which
should be the local ionic potential) and the non-local part which is
V_NL. In the USPP,
V_NL=sum_ij (D_ij *|beta_i> <beta_j|
My question is: in PWscf, how to get out the non-local potential V_NL.
Where are the D_ij and |beta_i> stored?  In the paper Vanderbilt, PRB
41, 7892 (1990), the author suggested that "the pseudopotential itself
must be updated as part of the self-consistent screening process". I
wonder whether PWscf does this in the self-consistent iterations. If
yes, where are the new pseudopotentials stored? Regarding to the
non-local psedupotential, I guess, in the pp.x, the total potential
V_bare+V_H + V_xc doesn't contain the non-local part V_NL, right?  Do
the V_bare and local ionic potential refer to the same thing? Or what
does the V_bare mean here?

I am sorry for all these questions, but I really appreciate you for
your helpful responses.

Best regards,
Zhiping Yin

On 3/23/07, Guido Fratesi <fratesi at mater.unimib.it> wrote:
>  | Thanks very much! I am not sure the exact meaning of the "local ionic
>  | potential" in Pwscf. Can you explain it in more details?
> Please have a look at Vanderbilt, PRB 41, 7892 (1990)
> (pw.x sums vloc for all atoms)
> Pseudopotentials are explained also in modern textbooks like
> Electronic Structure: Basic Theory and Practical Methods
> by Richard M. Martin, published by Cambridge University Press, 2004
> Regards,
> Guido Fratesi
> Dipartimento di Scienza dei Materiali
> Universita` degli studi di Milano-Bicocca
> via Cozzi 53, 20125 Milano, Italy
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Zhiping Yin
graduate student
department of physics
UC Davis

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