Steering ultrafast photochemical reactions with infrared excitation
| Dates: | 8 December 2021 |
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| Times: | 13:00 - 14:00 |
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| What is it: | Seminar |
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| Organiser: | Photon Science Institute |
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| Who is it for: | University staff, Current University students |
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| Speaker: | Prof. Julia Weinstein |
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Join us for this PSI seminar with guest speaker Prof. Julia Weinstein. Light absorption in molecules initiates a plethora of reactions on the ultrafast timescale. Designing the ways to control such processes, and direct light energy along a preselected pathway, is a fascinating problem that has been capturing scientists' imagination for decades if not centuries. One process of particular interest is photoinduced electron transfer, which is the primary step in photosynthesis and many applications related to light-harvesting and photocatalysis. Our approach to controlling photoinduced electron transfer is to change vibronic interactions in the excited state using mode-specific IR-excitation. We show that the yield of an electron transfer reactions in the excited state can be radically altered – from 100% to none - by mode-specific infrared excitation of vibrations which are coupled to the electron transfer pathway. It was particularly surprising to see this effect at work in solution! Some proposed design criteria necessary to achieve such an effect will be discussed, and illustrated on the example of photoactive Pt(II)-based systems - Donor-Acceptor pairs that are similar in design to molecular systems utilized in chemical and biological light harvesting (aka photosynthesis!). We will also discuss how multipulse experiments, such as UV(pump)-IR(pump)-IR(probe) and a beautiful method of two-dimensional infrared spectroscopy, 2DIR, are used in such experiments and help identifying reaction coordinate.
Delor et al, Toward control of electron transfer in donor-acceptor molecules by bond-specific infrared excitation. Science 2014, 1492, doi:10.1126/science.1259995;
Directing the path of light-induced electron transfer at a molecular fork using vibrational excitation. Nature Chemistry, 2017, 9(11), 1099-1104. doi:10.1038/nchem.2793
This event will be taking place online and furthers details about the event and how to join will be made available shortly.
Speaker
Prof. Julia Weinstein
Organisation: University of Sheffield
Biography: Julia Weinstein is a Professor of Physical Chemistry at the Department of Chemistry, the University of Sheffield. Julia obtained her Diploma in Chemistry (with honours) from Moscow Lomonosov State University in 1990, followed by a PhD from the same institution in 1994, on "The role of exciplexes in the mechanism of electron transfer in Marcus's kinetic region". She has been a member of the academic staff at the MSU since 1994. In 2000, she became a Royal Society/NATO Postdoctoral Fellow at the University of Nottingham, which was followed by a temporary lectureship at the same institution. Julia was awarded an EPSRC Advanced Research Fellowship in 2004 on "Light-Switchable Molecular Devices based on Metal Chromophores". She joined the Department in Sheffield in 2005.
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This event will take place online
