Skip to main content
Mechanistic organic photochemistry with machine-learning-accelerated photodynamics simulations
Add to Calendar 2023-04-26T18:30:00 2023-04-26T19:30:00 UTC Mechanistic organic photochemistry with machine-learning-accelerated photodynamics simulations 301A Chemistry Building
Start DateWed, Apr 26, 2023
2:30 PM
End DateWed, Apr 26, 2023
3:30 PM
Presented By
Steven Lopez - Northeastern University
Event Series: Chemistry Department Organic Seminar Series Spring 2023
steven lopez

Steven Lopez - Northeastern University


Photochemical reactions are increasingly important for constructing value-added, strained organic architectures. Direct excitation and photoredox reactions typically require mild conditions to access therapeutic gases (e.g., carbon monoxide) and new synthetic methodologies. A priori design of photochemical reactions is challenging because degenerate excited states often result in competing reaction mechanisms to undesired products. Further, a lack of experimental techniques that provide atomistic structural information on ultrafast timescales (10–15 – 10–12 s) has limited general rules about these reactions. Computations, however, provide a path forward. I will discuss how my group has leveraged multiconfigurational complete active space self consistent field (CASSCF) calculations, non-adiabatic molecular dynamics, and machine learning (ML) techniques to understand reaction mechanisms and enumerate new reaction pathways. I will introduce our new open-access machine learning tool, Python Rapid Artificial Intelligence Ab Initio Molecular Dynamics (PyRAI2MD), which enables 100,000-fold longer simulations than current NAMD simulations with multiconfigurational quantum chemical methods. I will describe how PyRAI2MD has enabled the first ML-NAMD simulations with QM/QM (CAS/HF) training data. The presentation will explain the origins of the reactivities and selectivities of photochemical pericyclic reactions and CO-evolving reactions in aqueous environments.