Slow neutron scattering by molecules

Explicit exact calculations are given for the scattering cross-section for slow neutrons for homonuclear molecular gases for time-of-flight instruments. It is shown that the recoil and detector (Placzek) corrections can be readily estimated using simple formulae by a modification to the first-order Placzek correction procedure and which is capable of generalization to any molecule. Although the procedure is for molecular gases it is expected that the corrections will apply almost equally well to molecular liquids.