Surface-enhanced Raman spectroscopy (SERS) is a powerful analytical technique that can detect single molecules and simultaneously obtain structural information. When an analyte molecule binds to a nanostructured noble metal surface, the otherwise weak normal Raman signal is enhanced by as much as a factor of 108. This makes SERS the...
Human skin oils are significant scavengers of atmospheric oxidants in occupied indoor environments. Many techniques used to study gas-phase transformations of surface films indoors have been limited to off-line bulk analysis, although more surface-selective methodologies are emerging. Here, we present a multi-prong analytical approach to characterizing skin oil ozonolysis. Skin...
This thesis document is comprised of three research projects. The first investigates the active vibrational modes involved in twisted intramolecular charge transfer in a Julolidine-BODIPY dyad using two-dimensional electronic spectroscopy along with DFT calculations. We identified two types of vibrations, compression and torsional motion, as playing an important role in...
Many processes in nature and human-made settings rely on the unique properties of charged metal oxide:aqueous interfaces. Despite their ubiquity, these buried interfaces are challenging to study, since any analytical technique aiming to overcome the relatively small number density of interfacial versus bulk species must be highly sensitive and surface-selective....
This dissertation focuses on the study of the superionic state in multicomponent systems, where the smaller component exhibits delocalization and mobility while still maintaining system compactness through component attractions. Superionic behavior is widely observed in various systems and plays a crucial role in ceramic superionic conductors, which offer high ion...
This manuscript describes and contextualizes the research I performed as a PhD student in Northwestern University. The first three chapters, on Markov chains, stochastic thermodynamics, and large deviation theory, describe three interrelated topics that serve as the background for subsequent research detailed in the next three chapters, on understanding the...
Despite the increasing interest in biogenic secondary organic aerosols (SOAs), their role in the climate system remains the greatest source of uncertainty in global models. Cloud formation, critical for the net cooling effect provided by cloud cover, is dependent on the abundance of SOA particles and their ability to activate...
Recent progress in semiconductor synthesis and photophysics has revealed a host of new materials with exciting properties for applications in optoelectronic devices such as sensors, photovoltaics, solid state lighting, and more. One of the most significant recent additions to the field is the class of hybrid and inorganic materials that...
How molecular chirality manifests at the nano- to macroscale has been a scientific puzzle since Louis Pasteur discovered biochirality. In general, amphiphilic molecules can organize into a variety of assembly shapes including micelles, spherical vesicles, cylindrical micelles, and planar bilayers. However, when such amphiphilic molecules are chiral, helical ribbons, helicoidal...
Understanding the photophysical processes of organic materials is important for utilizing them as functional photonic materials. Typical photophysical processes include intersystem crossing, charge transfer (CT), symmetry-breaking charge separation (SB-CS), singlet fission (SF), etc. There are serval factors that can lead to different photophysical processes, such as the molecular energy levels,...