  We use core-valence-valence (CVV) Auger spectra to probe the Coulomb
repulsion between holes in the valence band of Fe pnictide superconductors. By
comparing the two-hole final state spectra to density functional theory
calculations of the single particle density of states, we extract a measure of
the electron correlations that exist in these systems. Our results show that
the Coulomb repulsion is highly screened and can definitively be considered as
weak. We also find that there are differences between the 1111 and 122 families
and even a small variation as a function of the doping, x, in Ba(Fe1 xCox)2As2.
We discuss how the values of the hole-hole Coulomb repulsion obtained from our
study relate to the onsite Coulomb parameter "U" used in model and first
principles calculations based on dynamical mean field theory, and establish an
upper bound for its effective value. Our results impose stringent constraints
on model based phase diagrams
