Slow-Neutron Inelastic Scattering and the Dynamics of Heavy Water

The results of an extensive slow-neutron inelastic scattering study of heavy water at 299°K are reported. High-energy resolution measurements were made on thin D₂O samples to obtain the double-differential scattering cross sections for energy transfers to 7 kT and momentum transfers to 9.5 Å⁻¹. A spectral density for the modes of motion in D₂O has been obtained by an extrapolation technique. Experimental results are presented in the form of the Egelstaff scattering function and are compared with calculations based on the McMurry-Russell modification of the Nelkin model for water and the Egelstaff-Schofield theory for an incoherent scatterer with a Gaussian self-correlation function.