[Pw_forum] external potential and partial wavefunctions
fratesi at mater.unimib.it
Mon Mar 26 12:25:47 CEST 2007
> 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?
pp.x plots the LOCAL part only, possibly adding Hartree and XC
contributions. One cannot plot as function of r a nonlocal potential.
The NL part is defined by matrix D and projectors beta. IT IS updated in
the scf cycle by PW/newd.f90 (variable deeq):
* projectors are read from the pseudopotential file
* D^0 (unscreened D) as well
* D = D^0 + \int V Q dr is computed by PW/newd.f90
Look at PRB 47, 10142 (1993), Laasonen, CPMD with Vanderbilt USPP in
particular Eq. (13) and following note discussing the screening of D.
Dipartimento di Scienza dei Materiali
Universita` degli studi di Milano-Bicocca
via Cozzi 53, 20125 Milano, Italy
Phone: +39 02 6448 5214
email: fratesi at mater.unimib.it
More information about the users