This award supports a visit by Dr. A.J. Sievers of the Laboratory of Atomic Physics & Materials Science Center of Cornell University to the University of Canterbury in Christchurch, New Zealand, to work with Dr. J.A. Campbell on a study of the infrared properties of glassy crystals. Glass crystals represent a new materials system in which the universal character of glass behavior in solids can be probed. Although X-ray diffraction shows that crystal retains its long range order in the glassy state, low temperature thermodynamic measurements show that an additional low energy spectrum appears identical to that found in glasses. Dr. Campbell proposes to grow and characterize glassy Ba(1-x)La(x)F(2+x) crystals where x is varied from 0.001 to 0.46 so that the glass parameter is altered in a systematic manner. Dr. Sievers proposes to carry out persistent IR spectral hole burning measurements on these systems to compare the concentration of low lying nonequilibrium states to the concentration of thermodynamic glassy states. This proposed application of the persistent IR spectral hole burning technique will provide a new methodology for investigating and quantifying the physical characteristics of the low lying states in glasses. These experiments may also lead to a new understanding of processes influencing optical materials applications such as the relaxation behavior of optical excitations in laser glasses and the permanence of high density optical storage in glassy hosts.
