Non-adiabatic dynamics simulations of light-driven chemistry at surfaces

In molecular photochemistry, incident light triggers an electronic excitation. The consequence of this is ultrafast coupled electron-nuclear dynamics and the associated breakdown of the Born-Oppenheimer approximation. Similarly, light-driven electronic excitations can selectively promote chemical reactions at metal catalyst surfaces.

While experimental evidence for this exists for examples such as carbon dioxide reduction and hydrogenation and hydrogen dissociation, the underlying mechanisms and design parameters and the role of excited electron distributions in the metal are still mostly unresolved. This project will develop novel molecular simulation techniques that capture the intricate interplay of light, electrons, and atoms in surface photochemistry.

Light excitation of metals and metal nanoparticles involves light-matter coupling, electron-electron scattering, electron-phonon scattering, and electron-nuclear coupling between metal and adsorbate. This leads to ultrafast energy dissipation effects across the molecule metal interface, resonant charge-transfer, and even coherent quantum dynamical effects.

Novel mixed quantum-classical simulation methods will be developed that incorporate these effects and validated on well characterized model systems.

Once established, the newly developed methods will be used to simulate light-driven chemical transformations such as the promotion of CO hydrogenation to CHO on plasmonic catalyst materials. This will establish the mechanistic details of hot electron interaction with molecular adsorbates and the key design parameters for optimal photocatalytic transformations on metal catalysts of varying surface termination and composition, which will inform experimental design.

The project is closely aligned with the EPSRC investment areas computational and theoretical chemistry, Chemical reaction dynamics and mechanisms, and catalysis.