[Wien] Choosing proper Emin in electron density plot

[Shu Miao]

Dear Wien2k users
There are some discussions about setting Emin in case.in2 when plotting
the electron density on the mailinglist early this year. Some good hints
were given. However, clearer conclusion may be more informative especially
for new users, e.g., me. I want to take the TiC as example to work out
the right way by following those hints. Please give your advice.
In the TiC.scf file, I find the eigenvalues:
-3.4310763   -1.6693347   -1.6693347   -1.6693347   -0.1792457
 0.7811822    0.7811822    0.7811822    0.8523448    0.8523448
 0.8523448    0.8563761    0.8563761    1.4909371    1.7608187
The multiplicities for both Ti and C are 1. So I assign the states as:
-3.4310763 Ti-3s
-1.6693347 Ti-3p
-0.1792457 C-2s
 0.7811822 C-2p
The 5 values around 0.85*** are close but not same, since they are
forming band due to bonding effects in solid. They corresponds to the
partially-filled valence states Ti-3d.
The Fermi level is at 0.73236 just slightly below the C-2p which is not
full. So it seems above assignment is correct. An Emin set between
-0.1792457~0.7811822 should be able to exclude all semicore states in Ti
and C.
In TiC.scf, there is also "Energy to separate semicore and valencestates:
0.25298". This value is consistent with above reasoning.
However, the value in the UG is -1.0. Why this value? Is there any other
consideration I missed? Will a deeper Emin just include a constant
part of electron density from semicore states and won't cause big error if
we only want to know the difference between different plotting?
Please give your advice, whatever it is empirical, technical or
theoretical.
Thanks

Shu Miao