Over the past two decades, terahertz (THz) time-domain spectroscopy has become a valuable technique for the characterization of solid samples, primarily due to its sensitivity to bulk molecular packing arrangements. However, in recent years the role that specific THz vibrations play in a number of important physical phenomena has become increasingly apparent, with numerous studies highlighting how THz motions are directly responsible for the functioning of materials, ranging from enzymatic catalysis to solid-state phase transformations. Such dynamics are intimately linked to the molecular structures, condensed phase geometries, and even electronic configurations, and therefore understanding material properties is intrinsically linked to understanding the associated low-frequency dynamics.
In this work, the nature of THz-frequency motions in molecular solids, coupled with state-of-the-art ab initio quantum mechanical simulations, will be used to interpret, characterize, and predict a number of physical characteristics related to energy storage and generation in advanced materials. Specifically, THz vibrations in metalorganic frameworks will be shown to be directly related to the bulk mechanical properties, where they in turn dictate properties such as gas storage and sequestration.
Additionally, the role of THz phonons in determining the type and nature of dynamic disorder in organic semiconducting crystals will be highlighted, with specific attention paid to understanding the nature of the forces that result in large electron-phonon couplings and thus hinder charge carrier mobilities in such materials. In both of these studies, the understanding gained through THz characterization is enabling the guided and rational design of new materials, ultimately showcasing the utility of THz spectroscopy for the complete characterization of advanced materials.
Refreshments will be served in Olin Hall 118 at 3:30 P.M.