Scattering of Slow Neutrons by Solid and Liquid Terphenyls

The partial differential cross sections for scattering of slow neutrons by samples of solid and liquid terphenyls were measured and are presented in scattering law form. These data show that the difference between the scattering from the liquid and the solid is principally of magnitude and not shape. No effects due to the ortho-, meta-, or para-chemical binding is evident. Resonances attributed to transitions between vibrational states in the molecule are seen in the liquid data but not in the solid data. Fourier inversion of the scattering-law data show that the space-time self-correlation function $G_s(\overline{r}, t)$ for these materials is not Gaussian. A comparison of these data with other available scattering-law curves indicate that the curves may be grouped into classes of (1) polycrystalline solids, (2) liquid-amorphous solids, and (3) gases. The total cross sections for the terphenyls for 0.0251 ev neutrons were also measured.