Ultrafast Mechanics of Molecular Liquids and Solids: Vibrational and Structural Relaxation

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

This project aims to understand the mechanical dynamics of molecular liquids and solids at a fundamental level. The largest of two distinct but related thrusts involves the development and use of a new technique termed three dimensional (3D) Infrared-Raman spectroscopy. With three dimensional Infrared-Raman spectroscopy it is possible to study how vibrational energy flows through molecules, and how liquid state structures evolve in time. Important liquids such as water and methanol at room temperature will be studied to improve the laser apparatus and advance a theoretical understanding of 3D spectroscopy. A low temperature apparatus is being developed to study temperature dependence of these liquids and cryogenic solids. The smaller thrust involves the development and use of a shock wave spectroscopy technique to study supercooled liquids such as glasses and polymers which have slow structural relaxation dynamics. This technique is also referred to as the nanoshock technique. It produces large amplitude structural distortions in materials and then uses vibrational spectroscopy to monitor structural evolution back toward the original structure. This project involves the development of new instrumentation to study phenomena such as energy flow and how structures evolve in complex systems such as proteins and polymers. The relevance of this project to topics such as the accelerated aging of structural and biological materials is high, and students trained in these areas should be very competitive in the job market in areas of materials and biosciences of high interest to industry.