Do this thought experiment: take a structure with, say, 5 different inequivalent positions for the same element, and then do something unphysical: replace on one of the positions only the element by the next element in the periodic table. Would that really matter? Well...
Or do the following computer experiment: calculate hypothetical bcc-U with and without spin-orbit coupling, and see what the difference on the total energy is (this would also be a way to explore the effect of Emax on spin-orbit coupling -- cfr. one of your previous posts). Stefaan > Consider an atom A (heavy element) with let us say, 5 different non > equivalent atoms in the crystal lattice. > > During the spin orbit coupling initialization, we have to modify the > case.inso file. > > In case we incorporate only 4 atoms for so coupling and leave one of the > nonequivalent position, will it really matter in the SCF cycle for the > calculation of ENE?