QUASI-ELASTIC GAMMA-RAY SCATTERING FROM GLYCEROL

The Mossbauer scattering instrument at the Missouri University Research Reactor (MURR) has been used to study the liquid dynamics of glycerol as a function of temperature. The measurements were made by observing the Mossbauer gamma rays from the 46.5-keV level in W-183 scattered in the direction corresponding to the first liquid structure peak at Q = 1.36 Angstrom(-1). The widths of the Mossbauer velocity spectra were found to be quasielastically broadened by 3.1 mu eV at 24 degrees C up to 55 mu eV at 113 degrees C. The broadening varied quadratically with temperature above the melting point, but showed a linear dependence when plotted versus the absolute temperature divided by the viscosity. As discussed by Singh and Mullen, this latter dependence is expected in the continuous diffusion limit. The original analysis by Singwi and Sojlander was carried out for a diffusing Mossbauer ion, where the observed cross section is the Fourier transform of the self-correlation function. Our case requires the use of the pair-correlation function. Quantitative calculations as well as further experiments are needed.