Slow-Neutron Scattering by Hindered Rotators

Abstract

Using a description of a rotator in a strong static electric field the scattering of low-energy neutrons by a condensed system of polar molecules with only rotational degrees of freedom is discussed. Energy and angular differential scattering cross sections for symmetric and linear molecules are derived. It is shown in the case of symmetric molecules that there exist inelastic effects of the same order of magnitude as free-rotation transitions. A simple expression useful for the description of hindered rotation excitations is given. The cross section for water is computed and compared with measurements and existing theory.