My research broadly seeks to understand and characterize the atomic distribution and structure of crystalline solids using advanced spectroscopic and computational techniques. My laboratory work focuses on the atomic arrangement of typically minor, but important, species or elements added to crystals - a question that pertains to numerous technologically and geologically important materials. My research has pushed the frontier of using solid-state nuclear magnetic resonance (NMR), my main spectroscopic tool, to investigate paramagnetic materials and determine the site preference of incompatible elements at the 100's of ug/g level.
As a "people person" at heart, I am especially excited about joining a collaborative faculty setting, where my interdisciplinary mindset and leadership skills can play a key part in solving especially challenging research questions.Research directions
- Optical materials
- Catalytic materials
- Geologic mineralogy
- Simple software research tools
- Opening scientific research
Optical materialsStudying optical materials from new perspectives. My research has introduced paramagnetic NMR as powerful method for studying solid-state laser materials.
Optical materials play many key roles in the technological progress of our world, from enabling self-driving cars to detect pedestrians to reflecting the beam of light that enabled the detection of gravity waves. These materials' usefulness often depends on subtle changes to chemical composition and atomic arrangement; tailoring this composition can affect optic qualities. Additionally, many of the qualities that make optical materials great for optics also make them fascinating playgrounds for learning more about the complex nature of chemical bonding and distribution.
The majority of spectroscopic research in this field uses (with little surprise) optical spectroscopy. While it is a powerful and aptly suited technique, it is, like all spectroscopy techniques, only able to observe part of the picture. My research has presented an efficient NMR spectroscopic approach that uses the effects of unpaired electronic spins to observe atomic distribution in optical grade materials such as laser, scintillators, and phosphors. In future work I intend to merge my expertise with low concentration NMR to investigate the formation and minimization of grain boundary defects in optical materials, a current problem limiting the application and effectiveness of multicrystalline solid-state laser materials.
Despite cement's widespread use and the enormous greenhouse gas emissions related to its production, the materials and methods used to produce cement have seen relatively small improvements over the last 190 years. The insight needed for creating the greener cements of tomorrow may actually come from a deeper understanding of the crystal structures and atomic species found in current and historic cements. My research in this aspect includes directed studies of key cement minerals, such as B-belite, as well as the application of computer algorithms to increase the capacity of spectroscopic techniques for studying these minerals.Electron microscopy of B-belite grains.The thermodynamics of phase stability can often be influenced by minor changes in composition. In the above image, B-belite grains are stabilized by adding 0.3 wt% Al.
In progress!Zirconia nanoparticles aggregated into a large sphere.
In contrast to the high purity of an engineering environment, the Earth presents a messy and dynamic workspace for studying matter. With the eyes of an experimentalist, I see the Earth as a large chemistry project that has been running for 4.6 B years. In addition to the shear variability and variety of natural materials present at the surface, Earth also provides materials from conditions that are unreasonable to replicate in a typical laboratory setting. Given this complexity of geologically-relevant questions, it is a perfect test ground to develop spectroscopic and analysis approaches. My work in geologic mineralogy has used NMR to identify possible mechanisms for incorporating trace elements into mantle minerals including forsterite, clinoenstatite, and periclase.Optical microscopy on crushed synthetic forsterite grains.
The exchange between engineering focused sciences (materials science, mechanical engineering, ceramics) and the Earth sciences (geology and environmental sciences) happens too seldom, and some of my current geological research involves testing synthesis methods that I believe will be significantly useful to future experimental petrologists.
Simple software research tools
While research is continually becoming more complex, I believe researchers can become more efficient in part by using simple software tools. Throughout my PhD, I developed a number of small programs that automated processes and expanded the size of datasets I could analyze. I am now in the process of reworking these tools for free distribution to a wider audience of researchers, and hope to continue developing free software tools that are intuitive to use and that increase scholarly productivity.
Opening scientific research
In addition to my experimental work, I am passionate about opening access to research to a larger share of our world. Specifically, I hope to play a role in returning research results to the (virtual) shelves of libraries to improve research communication. Libraries used to purchase printed materials from publishers (who served a very important role in disseminating paper copies of information), and these libraries would then provide, protect, and perpetuate this information. Since the library then owned the printed paper material, their users could look at this information as many times as they wanted, for as long as the library kept the material. Unfortunately, this model has drastically changed, in that libraries no longer hold the content which their patrons seek, and instead only own limited time "access keys" which the library patrons can use to get information off the digital shelves of publishing companies and societies. Since libraries don't own permanent copies of materials, contracts for access must be frequently struck and the content suppliers can demand ever increasing fees to see the material.
I believe that, with the capabilities of the internet, libraries could take a more active role in publishing to improve access to research and reduce overall publication costs. The internet is an incredibly cost effective medium that enables an unprecedented level of communication and an extremely low cost. (Don't take my word for it; look up how many people are served by Wikipedia and its yearly operating cost!) With the formatting capabilities of inexpensive programs such as Microsoft Word, most of the publishing process is already completed by the researcher, and other aspects, such as reviewing and associate editorships, are in many cases donated efforts. The responsibility, complexity and cost associated with hosting the scientific material could be put forth by libraries, incurring overall costs below current publication prices, and empowering them with digital shelves that parallel their physical ones.
An important effect of online and open access publications is that they give the general public (who in many cases contribute heavily to the funding of scientific and engineering research) easy access to see what it is they are paying for. This makes the true face of academia directly visible to the researchers of tomorrow, and the capacity to embark on research available to anyone with curiosity or intrigue.
Solid-state Nuclear Magnetic Resonance
My work in computational chemistry primarily studies diamagnetic and paramagnetic non-periodicity in otherwise periodic systems. Computational approaches enable both a prediction and possible interpretation of experimental results, in many cases enabling and extending conclusions drawn initially from expensive or difficult to obtain experimental NMR spectra. In most of my simulations, a single atomic species with unpaired electron spins is contained within a large diamagnetic oxide crystal, from which the Fermi-contact interactions and localized effects on the magnetic field can be estimated. Oftentimes, large probabilistic calculations paired with additional simulations are necessary to bridge the insight of the highly homogeneous computational simulations with the complex atomic distribution found in synthesized materials.
Some of the computational packages and tools I use are: Notepad++, HTCondor (a fantastic freely available software package that enables distributed computing), Crystal14, Quantum Espresso, GULP, Atomic Simulation Environment, MolDraw, and Mike Towler's Billy.
Electron probe micro analysisEPMA explains the crystallization history of this ceramic. As this ceramic cooled, zircon rich particles (in green) provided nucleation sites for long aluminum rich crystals (in purple). The remaining composition could not crystallize fast enough, and remains as a magnesium rich intergranular glass.