  We present exact results for the dynamical structure function, i.e.~the
density-density correlations for the 1/r^2 system of interacting particles at
three special values of the coupling constant. The results are interpreted in
terms of exact excitations of the model which are available from Bethe's
Ansatz, thereby throwing light on the quasi-particle content of the elementary
excitations. We also obtain the first moment of the discrete version of the
model, which provides a non-trivial check on its structure function. We show
that the property of spectrum saturation is a common feature of both versions.
