Neutron scattering in almost-classical liquids

A theory of quantum corrections for thermal-neutron scattering in almost-classical liquids is developed that goes beyond the usual quasiclassical approximations, which take only detailed balance and translational recoil into account, by also including quantum effects in the structure and dynamics of the liquid itself. The method that we use is similar to one which we have recently developed for calculating corrections for final-state interactions in deep-inelastic neutron scattering. In the present application the method requires an expansion of the moments of the dynamic structure factor in powers of ². We show that the required expansions can conveniently be obtained by an extension of a method due originally to Nelkin.