Scattering of Slow Neutrons by Deuterated Methane

The scattering of slow neutrons by gaseous deuterated methane has been computed. This case is of particular interest since contributions to the scattering from the direct scattering terms and the interference scattering terms can be comparable in magnitude. Plausible arguments are presented which suggest that an incident neutron energy of 0.1 eV is large enough so that experimental results on liquid C${\mathrm{D}}_4$ using neutrons of that energy could be confidently compared with the calculated results of this paper for a gas, without the difficulties caused by liquid effects in interpretating the scattering at smaller incident-neutron energies.