GGA pseudopotentials for Fe.

(Even if it were not strictly necessary, a pseudo-core helps to iron out
some numerical instabilities which appear near r=0 when the GGA is used.)

Fe.gga-cc.in: Pseudopotential with a 3d6-4s2 configuration.
The p-pseudo looks a bit ugly. Increasing r_c(p) (Fe.large-rp.inp )
fixes this, but is the pseudopotential more or less transferable?

Fe.4s13d7.inp: Pseudopotential with a 3d7-4s1 configuration.

(Test the above pseudopotentials with Fe.test.inp.)

Fe.sc.inp: Pseudopotential with the 3s and 3p electrons in the valence.
Note that, in order to test it, we need a special test file: Fe.test.sc.inp.

Fe.sc.opt.inp: Same as above, but with rcs roughly optimized for transferibility while keeping the pseudopotentials relatively soft.

(To test the small-core pseudos we need a special test file: Fe.test.sc.inp)

The "spin" files are experimental.
