Minimally Empirical, First Principles-Derived Reactive Potential for Accelerated Simulations of Chemically Interacting Systems

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With support from the Chemical Theory, Models, and Computational Methods (CTMC) program in the Division of Chemistry, Alex Mironenko of the University of Illinois at Urbana-Champaign is developing minimally empirical reactive interatomic potentials from first principles for accelerating chemical reaction simulations and materials discoveries. Quantum chemical methods being developed over the last 100 years have led to new molecules, materials, and reactions predicted on a computer, reducing the amount of costly trial-and-error experimentation. The methods, however, remain too expensive to describe all intricacies of chemical transformations. Data-driven approximate methods – so-called interatomic potentials – are more affordable but often miss essential physics and require large, expensive data sets for their accuracy. Mironenko will develop interatomic potentials that will incorporate all required physics at a low cost using an overlooked “chemical pseudo-potential” theory introduced in the 1960s. His research group will implement the method using general-purpose software and assess its performance on a chemical reaction of significance to renewable energy. More broadly, the technique aims to quantify and unify fundamental concepts of chemical reactivity and will be integrated into educational modules for both undergraduate and graduate students. This project will generalize the minimally empirical reactive potential, demonstrated for the simplest hydrogen clusters, to main-group elements containing s and p valence orbitals. Several hypotheses and ideas pertaining to the method will be tested, including, but not limited to (1) electronegativity equilibration, (2) effective atomic pseudo-potentials, and (3) analytical bond orders derived from the underlying quantum theory. The method will be implemented using general-purpose, parallelizable open-access software, designed to compute the reactive potential energy surface at a low computational cost. The method will be used to study the mechanism of organocatalytic C-C coupling of formaldehyde to form platform chemicals - C3 oxygenates. The choice is motivated by its impact and relative simplicity, enabling direct comparison of predictions with state-of-the-art ab initio methods. If successful, the proposed method will pave the way to systematically derived, minimally empirical, and transferable reactive potentials, thereby accelerating data generation and further enabling predictive computational chemistry, catalysis, and materials science. The research also has the potential to create new knowledge about the fundamental origins of elementary, textbook electronic structure theories (Huckel, molecular orbital theory), potentially opening up new approaches to the description/teaching of theoretical physical chemistry, in general.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.