Listed below are some examples of research by Stony Brook graduate students working at and supported by Brookhaven Lab:
John C. Lofaro Jr.
SBU-Chemistry Department; BNL-Chemistry Department; Advisor– Michael G. White
Metal Nanoparticles on Oxide Surfaces
The primary focus of this project is to build model catalytic systems that can be used to understand the role of particle-support interaction and particle morphology for understanding and improving catalysts. In particular, we are studying the group 11 (coinage) metals, such as copper and gold, supported on various oxide surfaces. Copper has been used as a catalyst for the industrial processes of water gas shift reaction (WGSR).1 This reaction, which converts carbon monoxide and water to carbon dioxide and hydrogen (CO + H2O → CO2 + H2), has become exceedingly important in recent years due to the push for hydrogen production, especially within the automobile industry.
At this time we are interested in studying simpler systems, so that we can control all aspects of the reaction. Experimentally we produce the metal nanoparticles using a simple thermal evaporator, which allows us to create a constant stream of neutral atoms that nucleate on the substrate surface. This set up allows us to have control over the coverage of particles that are deposited on a single crystal (TiO2, CeO2/YSZ) oxide surface, which has defects to aid in nucleation and are also able to contribute oxygen to the overall reaction. Once on the surface we can conduct Auger electron spectroscopy (AES), which allows us to determine the exact ratio of metal to surface. We also use temperature programmed desorption (TPD) to investigate the reactivity and stability of the systems.
SBU- Department of Chemistry; BNL-National Synchrotron Light Source
My research targets the study of debilitating neurodegenerative diseases, specifically Alzheimer’s disease and Lou Gehrig’s disease (ALS), with the use of synchrotron light. We utilize mouse models of the disease, to investigate the protein aggregates that form from the misfolded metal-binding proteins in each of these diseases. With X-ray fluorescence microscopy (µXRF) at beamline X27A of the NSLS, we are able to image the metal ion concentrations within affected tissue sections. The data allow us to determine how metal homeostasis is affected throughout the course of the disease and whether or not it is found within the protein aggregates. This is particularly important for redox-active metal ions like Cu and Fe, which are capable of inducing oxidative stress in the diseased state when they are not closely regulated. In conjunction with µXRF, IR microscopy is also performed, at beamline U2B, to determine specific chemical changes in the tissue as the disease progresses. Hopefully, these experiments will aid in a greater understanding of the diseases and ultimately contribute to a cure. For more details on our research group, please visit the Miller research group homepage.
SBU-Physics & Astronomy; BNL-Condensed Matter Theory
Doping is one of the most powerful tools for tuning the electromagnetic properties of material
s. Well known examples besides the famous cuprates and pnictides include cobaltates, dilute magnetic semi-conductors, manganites and graphite intercalation compounds. Yet, it is almost inevitable that dopants will introduce quenched disorder, making it very hard to study these important materials theoretically. Together with my advisor Wei Ku, I have developed a method to study disordered systems fromfirst principles, using Wannier functions.
SBU-Computer Engineering; BNL-NSLS-II, HXN (Hard X-ray Nanoprobe Beamline)
My group is focusing on the creation of X-ray optics utilizing physical deposition systems. I have been working on process control, hardware interfacing, and microcontroller-based design for various aspects of the project. Some of my specialized software projects have included an SEM image analysis program to help verify the proper creation of an important X-ray focusing optic called a Multilayer Laue Lens, a process control system for a small rotary deposition system, and a customizable mask calculation system for precisely controlling magnetron sputtering.
SBU-Chemistry; BNL-Chemistry; Advisor-Michael G White
My research project in BNL focuses on the technique called “two-photon photoemission” (2PPE) which is a kind of photoelectron spectroscopy and allows to investigate the unoccupied state between the vacuum level and the Fermi level. In our 2PPE experiment, the ultrafast Ti:sapphire laser beam is tripled and doubled in frequency and used to excite the electron as “pump” and “probe”. We use this technique to study the electronic properties at the metal-molecule interface which is essential for charge transfer in molecular electronics. For example, the position of LUMO/HOMO state of the adsorbate with respect to the Fermi level determines the electron/hole transfer barrier from the metal surface to the adsorbed molecules. By changing the photon energies, polarization of the pump and probe laser beam, and the delay time between the two beams, we could collect the energetic and momentum information as well as the lifetime of the electronic state. The other part of my research is to deposit nanometer-sized clusters on the surface using our size-selected cluster deposition apparatus which has a quadrupole mass filter to control the cluster size precisely. When the cluster size is reduced to nanometer order, the electron properties are expected to differ significantly from those of bulk due to the confinement effects. With 2PPE, we have the capability to study the size dependence of the electronic dynamics on the nanometer-sized clusters.
SBU-Biomedical Engineering; BNL-National Synchrotron Light Source
Alvin Acerbo is a graduate student at the Biomedical Engineering program at Stony Brook University. He is currently working towards his Ph.D. at the National Synchrotron Light Source under the guidance of Lisa Miller and Larry Carr. His research involves the analysis of bone formation in cell cultures and studying the effects of various osteoporosis drugs on this mechanism. The cell cultures are analyzed at various stages using synchrotron based Fourier Transform InfraRed (FTIR), X-ray Fluorescence (XRF) and transmission X-ray tomography (TXM). The combination of several of these imaging techniques allows for the quantification and correlation of various parameters as they relate to bone growth and quality. Alvin is working on several side projects related to his Ph.D. research, including quantifying and improving the contrast and spatial resolution of FTIR microspectroscopy using point spread function deconvolution, and new methods of FTIR data analysis.