[Wien] vacuum thickness

[Stefaan Cottenier]

>         I wonder how to reach a good vacuum thickness, from prior mail, a
possible strategy could be: When you see that e.g. surface properties or the
potential in the middle of the vacuum (directly printed in case.scf) do no
change any more, then you have reached a good vacuum thickness.
>         I just don't know which parameter printed in case.scf is the
potential in the middle of the vacuum.

Look at the :VZERO label. The Coulomb potential at z=0 and z=0.5 is printed
as v0c and v5c respectively. (either z=0 or z=0.5 will be the center of your
vacuum, and if not, you can always make it like that).

As repeated recently on the mailing list, a good physical quantity to
monitor vacuum thickness (and slab thickness as well) is the work function:

WF = (v0c or v5c) - :FER

Stefaan