The Global XAS Journal club is an ongoing virtual seminar series. The seminar for this week in the Americas/Europe time window is below -- you can forward this to interested persons in the XAS community but
please do not make any public posting (we've had problems with zoom-bombing). Please email me
seidler@uw.edu to be added to the direct mailing list, where you would get this information for both the Americas/Europe and also Asia-Oceania/Europe timed seminars. About 70 prior lectures are available at the youtube channel
https://www.youtube.com/channel/UCwtkyiTV4BltKTQ7tS0CltQ/videos(1) XAS speakers who are early career scientists, such as postdocs, assistant professors, or new staff scientists at facilities and national labs, and
(2) beamline scientists to speak about capabilities and science outcomes/goals at their beamlines.
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X-ray Spectroscopy of Light-induced Chemical Reactions -- A New Universal Probe of Photoexcited Molecular Dynamics
Prof. Aditi Bhattacherjee (University of Iowa)
Thursday July 15: 9 am Seattle (PDT), 12 noon NY, 5 pm London, 6 pm Berlin, 7 pm Moscow
Abstract: Photochemical reactions of small organic molecules are prevalent in the atmosphere, in biological machineries and photocatalytic materials. Recent laboratory breakthroughs have enabled access to ultrafast X-ray spectroscopy at the carbon K-edge (1s absorption edge of carbon, at 284 electron volts). This has opened new avenues to explore ultrafast reaction mechanisms in a host of photochemical reactions in small molecules with high temporal resolution.[1] In this talk, I will discuss experiments that show how the excitation of 1s-core electrons of the constituent carbon atoms in organic molecules is a key spectroscopic probe of photoinduced molecular dynamics.
First, I will present the mechanistic details that emerge in the ultrafast ring-opening reactions of hydrocarbon as well as heteronuclear organic molecules from the direct orbital sensitivity of time-resolved X-ray absorption spectroscopy at the near edge.[2,3] Second, I will also show that in favorable cases, ultrafast intersystem crossing in molecules can be identified even though X-ray absorption spectroscopy is not directly sensitive to spin states.[4] Our work reveals that future chemical applications of this method at multiple absorption edges may provide new universal spectroscopic probes of photoinduced molecular dynamics.
Suggested reading:
[1] Bhattacherjee and Leone AccChemRes 21, 3203, 2018.
https://pubs.acs.org/doi/10.1021/acs.accounts.8b00462[2] Attar, Bhattacherjee, Das, Schnorr, Closser, Prendergast, and Leone Science 356, 54, 2017.
https://science.sciencemag.org/content/356/6333/54[3] Bhattacherjee, Schnorr, Oesterling, Yang, Xue, Vivie-Riedle and Leone JAmChemSoc 140, 39, 12538, 2018.
https://pubs.acs.org/doi/10.1021/jacs.8b07155[4] Bhattacherjee, Das, Schnorr, Attar and Leone JAmChemSoc 139, 46, 2017.
https://pubs.acs.org/doi/abs/10.1021/jacs.7b07532