Measurement of Interionic Potentials in Solids Using Deep-Inelastic Neutron Scattering

A quasiclassical approximation that we develop is used to obtain, in a simple way, the range of validity of the impulse approximation. We show that at energy transfers readily obtained in pulsed neutron sources, the neutron-scattering cross section for ions bound in a solid is accurately described by the impulse-approximation limit. A new and practical method of inverting the Radon transform that describes $S(q, \omega )$ in this limit is provided, that may be of use in other areas as well. The momentum distribution obtained in this way may be used to infer the interionic potential for light ions in a heavy host.