Heterogeneous Dynamics in Disordered Materials by Spectroscopy

Arizona State University, Scottsdale AZ

Investigators

Abstract

CHE-0204065 PI: Richert, Ranko In this project, funded by the Experimental Physical Chemistry Program of the Chemistry Division, Richert will perform research using triplet state solvation dynamics to study relaxation and dynamical heterogeneity in glass-forming liquids. Experiments will be performed on probe rotation, polarization-angle-dependent detection of the solvation time correlation function, and heterogeneity on the microsecond to nanosecond time scales. A new technique developed by Richert allows the first simultaneous measurement of probe rotational dynamics and solvation dynamics. This project deals with the important topic of how supercooled liquids make a transition to the solid state of aggregation. Many previous experiments have pointed to the existence of heterogeneous regions in the otherwise homogeneous liquid, with the heterogeneous regions exhibiting different dynamical behaviors from the homogeneous ones. The principal investigator has invented a unique technique by means of which the properties of the heterogeneous regions can be obtained separately from the homogeneous ones in a single experiment. Great advances in the understanding of the liquid to glass transition are expected to result from this research, with potential applications to polymer science and plastic crystals. Students will participate in this research.