Dear Suza, The Hubbard correction to the energy is determined as a function of the occupation of the Hubbard orbitals (such as d for Pb). How do we find the occupation of these orbitals? By projecting the Kohn Sham orbitals (KS) on the Hubbard orbitals (d) : |<d|KS>|^2 * (occ. of |KS>)
Now perhaps you can answer your own question: If you have constructed your system with only s and p electrons of Pb (5d in the core ) how would the projection of Kohn Sham solutions of this system on Pb 5d would look like? Would this projection be what you want to apply U with ? Then there is the technical part of where to read the Hubbard orbitals from, if they are not written in pseudo. But there are alternatives for that. I think the other question above is more significant. About the two different hubbard U for two different orbitals on the same site question: We have implemented this recently in the current version of the code, it is still very fresh and we are testing it. The U+V formalism[1] allows >1 orbital per site to have U correction, and even off-site correction. It is indeed physically meaningful, and easy to understand from the piecewise linearity picture (or at least that is how i understand [2] :) best emine kucukbenli, postdoc at theos, epfl, switzerland [1]V. L. Campo Jr. and M. Cococcioni, "Extended DFT+U+V method with on-site and inter-site electronic interactions", Journal of Physics: Condensed Matter 22, 055602 (2010) [2]I think Cococcioni's thesis explains this link between piecewise linearity and U very well: www.sissa.it/cm/thesis/2002/cococcioni.pdf -------------- next part -------------- An HTML attachment was scrubbed... URL: http://pwscf.org/pipermail/pw_forum/attachments/20130428/38e41448/attachment.html
