BEGIN:VCALENDAR VERSION:2.0 PRODID:-//ZContent.net//ZapCalLib 1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT SUMMARY:Photodynamics simulations explain photochemical reactivity and sele ctivities towards strained molecules LOCATION:Chemistry A101 TZID:America/Denver DTSTART:20210902T160000 UID:2026-05-21-19-59-37@natsci.colostate.edu DTSTAMP:20260521T195937 Description:About the Seminar\n\nPhotochemical reactions are increasingly important for the construction of value-added\, strained organic architect ures. Direct excitation and photoredox reactions typically require mild co nditions and permit access highly strained molecules and new synthetic met hodologies. The a priori design of photochemical reactions is challengin g because degenerate excited states often result in competing reaction mec hanisms to undesired products. Further\, a lack of experimental techniques that provide atomistic structural information on ultrafast timescales (10 –15 – 10–12 s) limits general ‘chemical intuition’ about these processes.  Computations\, however\, provide a path forward. I will disc uss how my group has leveraged state-of-the-art quantum mechanical calcula tions\, non-adiabatic molecular dynamics\, and machine learning (ML) techn iques to understand the reactivities and selectivities of a photochemical cascade reaction towards the first stable polyacetylene\, fluoropolyacetyl ene. I will introduce our new open-access machine learning tool\, Python Rapid Artificial Intelligence Ab Initio Molecular Dynamics (PyRAI2MD)\,  which enables 1\,000-fold longer simulations than are currently possible with multiconfigurational NAMD simulations. PyRAI2MD has enabled nanoseco nd ML-NAMD simulations on stereoselective electrocyclic reactions with rec ord degrees of freedom and molecular complexities. 4:00 pm END:VEVENT END:VCALENDAR