[Wien] unscreened hubbard parameter U

[Amene Nouri]

Hello WIEN2k users
I have a question about using the method introduced by Madsen and Novak for calculation hubbard parameter of LDA+U. Do you think it is correct to calculate unscreened atomic U?
I used this method by using supercells with 20 bohr lattice constant. The result that I found is one order of magnitude smaller than what I expected. For example I found it 4.5 eV for Fe but the correct one is 24 ev.
Do you have any suggestion?
Thanks in advance