An X-ray diffraction study of the structure and molecular motion in liquid carbon disulfide

Abstract

X-ray diffraction intensities from liquid carbon disulfide were measured by the energy dispersive method at room temperature. The obtained intensity function was found to be consistent with that reported by Sandler and Narten in 1976 (S.I. Sandler and A.H. Narten, Mol. Phys., 32 (1976) 1543). It was well simulated by the local lattice structure model, where the orthorhombic cell of the crystalline phase was used and the cell parameters were slightly modified. In the optimized local lattice structure, the T-shaped configuration found in the crystalline phase manifests itself, as predicted theoretically by using the reference interaction site model (RISM) of Sandler and Narten. The structural diffusion in the liquid was represented by the mean-square deviations of the interatomic distances given by the Prins relation. The mean-square deviations were also calculated by using the frequency distribution of the librational motion determined by Ruhman et al. (S. Ruhman, B. Kohler, A.G. Joly and K.A. Nelson, Chem. Phys. Lett., 141 (1987) 16) by means of impulsive stimulated light scattering (ISS). They showed overall consistency with those given by the Prins relation. Thus the deviations of the distances within the structure region in liquid carbon disulfide seem to be mainly due to the librational motion of the molecules.