  Intermediate valence compounds containing rare earth or actinide ions are
archetypal systems for the investigation of strong electron correlations. Their
effective electron masses of 10 to 50 times the free electron mass result from
a hybridization of the highly localized $f$-electrons with the more itinerant
$d$-electrons, which is strong enough that their properties are dominated by
on-site electron correlations. To a remarkable degree, this can be modeled by
the Anderson Impurity Model, even though the $f$-electrons are situated on a
periodic lattice. However, in recent years, there has been increasing evidence
that the dynamic magnetic susceptibility of intermediate valence compounds is
not purely local, but shows variations across the Brillouin zone that have been
ascribed to $f$-band coherence. So far, this has been based on simplified
qualitative models. In this article, we present a quantitative comparison of
inelastic neutron scattering from a single crystal of CePd$_3$, measured in
four-dimensional (Q,$\omega$)-space, with ab initio calculations, which are in
excellent agreement on an absolute scale. Our results establish that the
Q-dependence of the scattering is caused by particle-hole excitations within
$f$-$d$ hybridized bands that grow in coherence with decreasing temperature.
