FIRST-PRINCIPLES QUANTUM CALCULATIONS OF CATALYTIC AND MECHANOCHEMICAL REACTIONS

Abstract

Anthropogenic climate change and pollution are the most pressing challenges of the ongoing environmental crisis. Addressing these challenges demands a shift towards cleaner, more sustainable methods. Traditional chemical processes often rely on energy-intensive methods and hazardous solvents. Mechanochemistry—an emerging field that uses mechanical force to drive chemical reactions—offers a revolutionary alternative to traditional methods by eliminating or significantly reducing the need for solvents, lowering energy consumption, and enabling novel reaction pathways. Mechanochemical methods have already been extensively demonstrated in the literature for a range of applications. However, a robust theoretical framework for understanding mechanochemical processes using quantum mechanical methods remains elusive.Through a combination of first-principles quantum chemical calculations and novel theoretical approaches, this work explores the role of mechanical forces at the molecular level. Various modeling techniques are employed to study hydrostatic pressures, normal stresses, and shear stresses in model systems. The rate enhancement of Diels-Alder reactions under hydrostatic pressures is investigated using a modified solvation model. Normal stresses are applied to adsorbed methyl thiolate on Cu(100) using a quasi-static approach, while a shear stress model derived from continuum mechanics is applied to adsorbed ethyl thiolate on Cu(100). Additionally, catastrophe theory is integrated to describe a critical stress phenomenon where certain molecular architectures can exhibit mechanochemical resistance. Beyond mechanochemistry, we also investigate the electronic structure and binding of oxygen on Pd/Au(100) single-atom alloys.