BEGIN:VCALENDAR VERSION:2.0 PRODID:-//ZContent.net//ZapCalLib 1.0//EN CALSCALE:GREGORIAN METHOD:PUBLISH BEGIN:VEVENT SUMMARY:Surprising reaction dynamics of molecules far-from-equilibrium LOCATION:Chemistry A101 TZID:America/Denver DTSTART:20230307T160000 UID:2026-04-05-14-55-27@natsci.colostate.edu DTSTAMP:20260405T145527 Description:About the Seminar\n\nChemists have always known that chemical r eactions involve bond formation and bond breaking events. Femtosecond time -resolved measurements have provided the timescales of fundamental bond br eaking and bond forming processes\; been used to confirm reaction mechanis ms in a wide range of systems (organic\, inorganic\, biological\, atmosphe ric\, etc.)\; and been instrumental to test electronic structure calculati ons as well as molecular dynamics simulations. However\, there are some c hemical reactions that are very difficult to study with femtosecond time r esolution. This talk will focus on the reaction dynamics of molecules far- from-equilibrium. In particular\, the multiple reactions that follow when a molecule absorbs tens of electron volts of energy following electron sca ttering\, a situation that occurs in every electron-ionization mass spectr ometer. Early theories have failed to predict the fragment ion patterns fo llowing electron ionization because the assumption of fast intramolecular energy distribution prior to fragmentation. Lack of dynamic information ha s prevented scientists from determining how fast the energy distributes an d how it affects bond breaking\, forming\, and rearrangements. Therefore\, currently predicting the fragmentation pattern of a given molecule is alm ost impossible. Similarly\, identifying a molecule based on its mass spect rum is only possible if its spectrum is already found in a database. The d ifficulty of these two tasks stems from our lack of knowledge about reacti on dynamics far-from-equilibrium. I will present femtosecond time-resolved measurements of multiple simultaneous reaction pathways [1] that reveal surprising examples of unexpected pathways that include roaming moieties [ 2]\, concerted dynamics\, and intramolecular rearrangements\, all occurrin g prior to intramolecular energy redistribution.\n\n Jochim\, L. Dejesus\ , M. Dantus\, “Ultrafast disruptive probing: simultaneously keeping trac k of tens of reaction pathways\,”\, Rev. Sci. Instr. 93\, 033003 (2022). \n Ekanayake\, et al\, “H2 roaming chemistry and the formation of H3+ f rom organic molecules in strong laser fields\,” Nat. Commun. 9\, 5186 (2 018).\n\n \;\n\nAbout the Speaker \n\nMarcos Dantus is a University D istinguished Professor and MSU Foundation Professor at Michigan State Univ ersity. He is affiliated with the Department of Chemistry and the Departme nt of Physics and Astronomy. Dantus obtained his undergraduate and master s degree in chemistry from Brandeis University (1985). He completed his Ph.D. (1991) and postdoctoral training (1993) at The California Institute of Technology in 1991 where he designed and built the first femtosecond la ser system to study ultrafast fundamental chemical processes\, and the fir st ultrafast electron diffraction system. This work was recognized by Calt ech’s Milton and Francis Clauser Doctoral Prize\, and was cited in the 1 999 Chemistry Nobel Prize given to his research advisor Ahmed Zewail.\n\nD antus is an accomplished scientist\, inventor\, and entrepreneur with 253 publications (h-index = 61)\, 33 issued and 5 pending patents. He is a pio neer in the use of spectrally and temporally shaped ultrafast pulses and t he inventor of revolutionary laser optimization instruments. His entrepren eurial endeavors include the commercialization of instruments that improve the performance of lasers\, biodegradable packaging materials\, and the d evelopment of fuel additives to reduce harmful emissions and improve combu stion efficiency.\n\nDantus’ honors include election as a fellow of the National Academy of Inventors\, the Optical Society of America\, and the A merican Physical Society. 4:00 pm END:VEVENT END:VCALENDAR