We develop theories and computer algorithms to reveal the underlying physical principles that govern the complex kinetics and dynamical behaviors of a variety of intriguing chemical systems, ranging from gas-phase collisions to interfacial and condensed-phase reactions, and to biological systems. We are interested in understanding the electronic structures and geometries of reactive intermediates, the reaction mechanisms, and the detailed kinetics of clean-energy-driven catalysis, including electrocatalysis and photocatalysis.