Department of Chemistry and Biochemistry
Physical Chemistry Seminar Series

Professor Jessica Anna, University of Pittsburgh
February 26, 2024—2:00pm
Tykeson 140

Elucidating Photoinduced Processes and Ultrafast Dynamics of Natural Light Harvesting Complexes and Model Systems

Photosynthetic organisms have developed the molecular level machinery to efficiently and effectively harvest solar energy. To accomplish this, they use natural multichromophoric assemblies called light harvesting complexes to absorb photons and transfer the excitation energy to reaction centers where charge separation can take place with a high quantum efficiency. Elucidating the mechanism of energy transfer and electron transfer in these complexes is essential to (1) understanding
their high quantum efficiencies and subsequently (2) incorporating this information into design principles for artificial photosynthetic systems and photocatalysts. However, given the complexity of natural light harvesting complexes, there are still questions regarding the mechanism of energy and electron transfer in these systems. In this talk I will discuss our recent studies in this area where we apply ultrafast pump-probe and multidimensional spectroscopies in the visible and mid-IR spectral regions to photosystem I, a large natural light harvesting complex, and structurally simpler model systems that mimic specific properties of light harvesting complexes, including artificial light harvesting chromophores, isolated cofactors, and transition metal complexes. From our studies we gain insight into pathways of energy equilibration among different electronic states, information on solvation dynamics, and insight into how non-covalent interactions and spatial confinement  can act to alter the properties and dynamics of molecules.