Hi all,
I have a doubt on the LDA+U implementation in siesta, more
specifically on the definition of U and J.
The siesta LDA+U manual states that "although the input allows to
define independent values of the U and J parameters for each atomic
shell, in the actual calculation the two parameters are combined to
produce an effective Coulomb repulsion U_{eff}=U-J. U_{eff} is the
parameter actually used in the calculation for the time being.". Now,
does that really mean what it seems to imply, namely that any
combination of U and J that produces a given U_{eff} will give me the
same final results? For example, if I want my U_{eff} to be 1.0 eV,
then U=0.6, J=0.4 and U=1.4 and J=-0.4 will give me the same final
results?
Cheers,
Marcos
