Miles Carlson and Evan Mader, “Bonding Teaching and Research: Computational Chemistry Exercises for Stem Education”
Mentor: Mohamed Ayoub, Mathematics & Natural Sciences
Poster #35
This research project aims to provide computational chemistry exercises for undergraduate chemistry and S.T.E.M. curriculum and research. The modeling exercises and problems will help the user gain proficiency using modern computational tools to express wavefunction (Ψ) and its associated chemical phenomena in terms of chemically intuitive descriptors, with minimal distractions from the underlying mathematical or programming details. They will also provide written instructions to a) acquaint with basic methods of computational chemistry and analysis to explore electronic properties and use of Natural Bond Orbital (NBO) graphic capabilities to visualize possible bonding patterns of chemical compounds to be able to qualitatively and quantitatively discover structure-reactivity relationship behind the chemistry observed; b) adapt the exercises widely to explore research in the S.T.E.M. areas; and c) bring in the computational chemistry component to complement formal theory and build a better bridge to the experimental field. Students readily and securely access the server to run calculations on their own personal computers remotely, using WebMO environment, a powerful web-based interface to popular computational chemistry packages. In this work we investigate hydrogen bonded complexes, using density functional theory and correlation-consistent, triple-z (aug-cc-pVTZ) basis followed by NBO and natural resonance theory (NRT) analysis to explore the unique causal charge transfer between donor-acceptor orbitals interaction and other distinctive hydrogen bonding properties, which include downfield 1H-chemical shifts of H-bonded nuclei, and red-shifting IR vibrational frequencies for H-bonded hydride bonds. Then we employ natural energy decomposition analysis (NEDA) to compute binding energy and its classical and nonclassical components to better understand the physical basis for their formation. Our preliminary result demonstrates that classical static and induced interactions of molecular charge densities are responsible for the long-range behavior of the interaction potential and that quantum mechanical effects only contribute at short range where the charge densities overlap considerably.