The scattering of slow neutrons by diatomic molecular fluids

Abstract

A calculation of the differential scattering cross section for molecules is needed to interpret neutron diffraction experiments on molecular gases or liquids. In this and a subsequent paper we improve the accuracy of existing calculations to the level achieved by modern experiments, typically 1 per cent. Some of the older models are reexamined and some difficulties with them are discussed. New models for the double differential cross section are presented and integrated numerically over the energy transfer to give the required cross sections. Some recent formulae for this cross section are criticized, and our results are compared to the predictions of these formulae to confirm that they give incorrect results.