  By ab initio LMTO calculations in atomic-sphere approximation we have studied
the interlayer exchange coupling between Fe films separated by Au spacers in
infinite Fe/Au multilayers with (001) interface orientation. We also performed
detailed calculations of the magnetization and charge profiles across the
system. We find an enhancement of the Fe moments at the interface, which amount
to $\approx 2.8$ $\mu_B$ instead of the bulk value of 2.2 $\mu_B$, and we also
find a slight magnetic polarization of the order of 0.01 $\mu_B$ at the Au
interface layers. These results do not depend sensitively on the lattice
constants assumed in the calculation.
  When we try to optimize our results with respect to the ratio $R_{Fe}/R_{Au}$
of the Wigner-Seitz spheres for the mutual components, we often find the
optimum near charge neutrality of the interface monolayers: However, this is
not always the case, and usually the sign and the magnitude of the exchange
coupling depend sensitively on the optimal choice of the above-mentioned ratio.
In particular, for Fe$_5$/Au$_3$ we find an anomaly with a large dipole moment
at the interface and a related anomaly of the exchange coupling.
