Light Scattering Studies of Molecular Dynamics in Molecular Crystals, Liquid Crystals and Polymers for Applications in Chemical Defense

摘要

A total of 16 papers have appeared in the literature dealing with both the theoretical and experimental (light scattering) investigation of phase transitions and critical phenomena in simple molecular solids. New Brillouin scattering data have been obtained for benzil single crystals near the phase transition at 83.5K. A mean field approach to the dynamics of structural phase transitions in molecular crystals has been developed. Brillouin scattering study of the successive phase transitions in methmmonium iron chloride. In addition to the magnetic transition at low temperature, this system also possesses successive structural phase transitions. These have been studied by means of lattice dynamics and far infrared spectroscopy, birefringenence, x-ray and neutron diffraction, specific heat and ultrasonic sound velocity measurements, and ultrasonic attentuation measurements. Also pursued were high pressure Raman, Brillouin, and Rayleigh scattering studies of benzene in a diamond anvil cell.