The Scattering of Slow Neutrons byO2Molecules

The scattering of slow neutrons by ${\mathrm{O}}_2$ is due to nuclear interaction as well as magnetic forces arising from two magnetically active electrons. The molecular (nuclear) scattering is subdivided into elastic (coherent and incoherent) transitions and inelastic (mostly hyperelastic) transitions. The magnetic scattering is purely incoherent and essentially elastic. Numerical values are obtained for the integral cross sections of these various scattering processes in dependence upon the wavelength. The case of very long neutron wavelength is of greatest physical interest, since only then can a sizable magnetic effect be expected. The analysis requires careful consideration of the thermal motion of the ${\mathrm{O}}_2$ molecules, which sometimes influences the order of magnitude of the result. More accurate experiments can be expected to lead to an independent measurement measurement of the distribution of the magnetically active shell of valence electrons.