Atomic Population Analysis of Complex Materials for Energy and Environmental Applications
Atomic population analysis methods are used to compute net atomic charges, atomic spin moments, bond orders, atomic multipoles, atomic polarizabilities, C6 dispersion coefficients, and other properties. These quantities provide key insights into electronic and magnetic ordering and chemical bonding in materials. In addition, net atomic charges, atomic polarizabilities, and C6 dispersion coefficients can be used to construct force-fields for atomistic (e.g., molecular dynamics and Monte Carlo) simulations of materials. The main challenge has been developing an atomic population analysis method that provides good accuracy across a wide range of materials with any form of magnetism (non-magnetic, collinear magnetism, and non-collinear magnetism) with or without periodic boundary conditions. My research group develops improved computational methods and computer codes for performing atomic population analysis and uses these to study complex materials for energy, catalytic, and environmental applications. Recently, we received NSF funding to develop automated methods to construct polarizable, flexible force-fields to design membranes using metal-organic frameworks to purify (a) helium from natural gas sources and (b) hydrogen from solar water splitting. An example metal-organic framework material is shown to the right.
Design of More Efficient Selective Oxidation Catalysts
Computational chemistry is an important tool for studying catalytic mechanisms in order to design more efficient catalysts and processes. Using computational chemistry, we designed a new class of organometallic catalysts that is predicted to catalyze selective oxidation of organic substrates via a new catalytic route. Our goal is to develop new catalysts and processes that facilitate the selective oxidation of challenging organic substrates (e.g., alkenes with allylic hydrogen atoms) using molecular oxygen as oxidant without using a co-reductant. Using molecular oxygen as the oxidant is desirable, because it is readily available in air. Eliminating the need for a co-reductant should avoid the formation of unwanted co-products. After extensively exploring these catalysts using density functional theory (DFT) computations, we have spent the last year in the lab doing experiments to try to develop a method to synthesize them. This represents an exciting new phase for us. Last year, we received NSF funding from the Innovation Corps program to explore potential product-market fit. As part of the I-Corps program we interviewed people from numerous chemical and pharmaceutical companies to better understand commercial needs.
In addition to the two projects described above, I occasionally work on other research projects. These will usually involve some novel mathematical or physical aspects that I believe have not been adequately researched and might provide some ground-breaking impacts. These topics could involve theoretical or experimental work, or both. To the right is shown an unusual effect that produces an attraction between two thin metallized dielectric foils have the same sign of electrostatic charges. I believe this may be the first known violation of Coulomb’s Law. As explained in one of my publications, I attribute this unusual attraction of like electrostatic charges to scattering of electromagnetic waves off the electrostatic potential kink that occurs at the positions of the confined charge layers. Additional research is required to better understand this effect.