Molecular motion in supercooled glycerol a Mössbauer scattering experiment

Rayleigh scattering of photons with λ=0·86 Å was applied to liquid glycerol at T=-16·5°C. Using the Mössbauer effect, the width and intensity of the quasi-elastic line as well as the inelastic scattering intensity were measured for momentum transfers between 0·6 Å-1 and 4·2 Å-1. A model of the molecular motions is developed in order to analyse the results quantitatively. It comprises the molecular structure factor, a radial distribution function for the centres of mass, random-walk diffusion of the centres of mass and of the molecular orientation, and a high frequency motion; translation-rotation coupling is assumed to produce a common jump time. The results are compared with other experiments, especially N.M.R. relaxation.