Exact evaluation of low-order moments of the imaginary part of the dynamic susceptibility is used to analyze inelastic neutron scattering in a paramagnetic intermediate-valence system. It is shown that (i) the second moment of χ′′(q→,ω)ω measures the mixing energy, (ii) only a weak q→ dependence of χ′′(q→,ω) is expected even in "coherent" systems, and (iii) there are no diffusive modes in the hydrodynamic regime. © 1979 The American Physical Society.421913051308