The d electrons in Cu can be treated
either as "core" or "valence" (and
actually as "core but corrected").

Exercises:

1. Generate and test the "3d in valence" 
   pseudopotential found here.

2. Prepare an input file for a
   "3d in core" pseudopotential. Generate
   the pseudo and test it.

3. Put core corrections to the pseudopotential
   of case 2.
