So Very Far Away

I began my thesis planning to craft pieces of both fiction and nonfiction. I had very much enjoyed working on a travel essay during the fall semester, but I have always had an inherent interest in writing short stories, so I had hoped to explore both genres, using my previous work from a seminar in fiction and a travel writing class as a springboard. However, in writing “So Very Far Away,” my second nonfiction piece, which I developed from material that I was unableto keep in the essay “Lunch with the Americans,” I discovered that nonfiction was an incredibly freeing genre because the essential ingredients were already present. My personal experiences provided the basic elements of plot, character, and setting, yet I discovered new challenges as I attempted to present these experiences in a way that moved beyond mere memories and reflections and towards a larger meaning that would matter to others as well. I became sointrigued by this process of creating cohesive narratives through the editing and shaping of memories that I decided to focus completely on nonfiction for my thesis work and write a collection of essays about my time abroad.

Au@Hg nanoalloy formation through direct amalgamation: Structural, spectroscopic, and computational evidence for slow nanoscale diffusion

Dynamic core-shell nanoparticles have received increasing attention in recent years. This paper presents a detailed study of Au-Hg nanoalloys, whose composing elements show a large difference in cohesive energy. A simple method to prepare Au@Hg particles with precise control over the composition up to 15 atom% mercury is introduced, based on reacting a citrate stabilized gold sol with elemental mercury. Transmission electron microscopy shows an increase of particle size with increasing mercury content and, together with X-ray powder diffraction, points towards the presence of a core-shell structure with a gold core surrounded by an Au-Hg solid solution layer. The amalgamation process is described by pseudo-zero-order reaction kinetics, which indicates slow dissolution of mercury in water as the rate determining step, followed by fast scavenging by nanoparticles in solution. Once adsorbed at the surface, slow diffusion of Hg into the particle lattice occurs, to a depth of ca. 3 nm, independent of Hg concentration. Discrete dipole approximation calculations relate the UV-vis spectra to the microscopic details of the nanoalloy structure. Segregation energies and metal distribution in the nanoalloys were modeled by density functional theory calculations. The results indicate slow metal interdiffusion at the nanoscale, which has important implications for synthetic methods aimed at core-shell particles.