Conferences, Lectures, & Seminars
Events for September
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Catalyst Discovery for Metal-Free, Photoredox CO2 Reduction
Tue, Sep 20, 2022 @ 04:00 PM - 05:20 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Speaker: Dr. Shaama Sharada, Assistant Professor
Talk Title: Catalyst Discovery for Metal-Free, Photoredox CO2 Reduction
Abstract: Organic photoredox catalysis will be an important part of an energy-efficient, sustainable future as these
catalysts can access highly reactive states upon excitation and quenching to carry out reactions that are
otherwise thermally inaccessible or energy-intensive. Our group aims to identify sustainable photoredox
routes for CO2 utilization. Prior experiments show that a simple organic chromophore, p-terphenyl, can
reduce and transform CO2 into useful molecules such as amino acids. However, the steps of the photoredox
cycle and reasons for low turnover numbers of these catalysts are poorly understood. Our goal is to utilize
quantum chemistry methods to delineate mechanisms of key steps in this cycle and leverage these insights to
drive discovery of novel chromophores that are both active and yield high turnover numbers. Thus far, we
have demonstrated that the electron transfer (ET) step from the p-terphenyl radical anion to CO2 is adiabatic,
and ET barriers are lowered when electron-donating groups are substituted to p- terminal positions of the
catalyst. To probe degradation pathways from the excited state, we are establishing a protocol for calculation
and characterization of excited-state donor-acceptor charge transfer complexes in collaboration with the
Dawlaty group (USC). We are also taking our first steps towards driving discovery of new chromophores by
implementing a genetic algorithm (GA) whose fitness function factors in both catalyst activity and
degradation resistance by means of simple descriptors obtained from routine DFT calculations. The GA yields
several candidates that are more viable than experimentally studied terphenyls, highlighting the importance of
automated computational tools in accelerating experimental efforts.
Biography: Dr. Shaama Mallikarjun Sharada is the WiSE Gabilan Assistant Professor in the Mork Family Department of
Chemical Engineering and Materials Science and Assistant Professor in the Department of Chemistry at USC.
Her research interests span the development and application of quantum chemistry methods to design catalysts
for sustainable chemistry transformations. Her group is developing efficient algorithms, inspired from signal
processing, for advancing sophisticated rate theories in catalysis. The group is also establishing frameworks for
catalyst design and discovery towards efficient natural gas conversion and light-assisted carbon dioxide
utilization. Dr. Sharada received her Bachelors and Masters in Chemical Engineering from the Indian Institute
of Technology, Bombay (India) where she was awarded the Institute Gold Medal. She received her PhD in
Chemical Engineering from UC Berkeley in 2015 for developing efficient reaction path search algorithms for
catalysis. As a postdoctoral researcher at Stanford University, her work spanned the development of machine
learning density functionals and surface chemistry benchmarking databases. She is a recipient of the 2022
inaugural Chevron Research Innovation Award (USC) and the 2020 ACS Petroleum Research Fund Doctoral New Investigator Award. She is also a Scialog Fellow for the Negative Emissions Science initiative.
Host: Mork Family Department
More Information: Shaama Sharada Seminar Flyer 9 20.pdf
Location: James H. Zumberge Hall Of Science (ZHS) - 352
Audiences: Everyone Is Invited
Contact: Anthony Tritto
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MFD Seminar: Control and Imaging of the Quantum Electron Motion in Action
Mon, Sep 26, 2022 @ 04:00 PM - 05:20 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Speaker: Dr. Mohammed Hassan, Physics Department and Optical Sciences, University of Arizona
Talk Title: Control and Imaging of the Quantum Electron Motion in Action
Abstract: The electron motion in atoms and molecules is at the heart of all phenomena in nature. The advances in ultrafast light field and synthesis and attosecond spectroscopy enabled tracing and controlling electron motion dynamics in matter. In the first part of this talk, Dr. Hassan will present our capability for on-demand tailoring of light field waveforms spanning two optical octaves, from near-infrared electron motion in dielectric using synthesized light waveforms. This fine control allowed for switching the optical signal with attosecond time resolution. Furthermore, he will introduce the possibility of encoding binary data on ultrashort laser pulses waveforms. This work paves the way for establishing optical switched and light-based electronics with petahertz speeds, several orders of magnitude faster than the current semiconductor-based electronics, opening a new realm in information technology, optical communications, and photonic processors technologies. Dr. Hassan will present a new methodology for all-optical light field sampling and electron meteorology, which allows measuring the electronic delay response in the dielectric system. In the second half of the talk, Dr. Hassan will present the latest results of imaging the quantum electron motion in solid-state in action. He will explain how his team was able to attain the native electron motion (attosecond) temporal resolution in the electron microscope, orders of magnitude faster than the highest reported imaging resolution, by generating a single-isolated attosecond electron pulse inside the microscope and the embellishment of what we call "Attomicroscopy". This attosecond electron imaging by Attomicroscopy provides more insights into the electron dynamics in real-time and space with attosecond and picometer resolutions and promises to find long-anticipated real-life attosecond science application in quantum physics, chemistry, and biology.
Biography: Education: Ph.D. Physics, 2013, Max-Plank Institute for Quantum Optics- Ludwig Maximilian University of Munich
Fields of Study: Atomic, Molecular, and Optical Physics; Condensed Matter Physics
Research Interests: Dr. Hassan''s research focuses on achieving the attosecond temporal resolution in electron microscopy by generative attosecond electron pulses and establishing the "Attomicroscopy" field, which will be utilized for recording film of electronic and atomic motion in action.
Host: Professor Moh El-Naggar (Dept of Physics and Astronomy Colloquium); Professor Andrea Martin Armani (Mork Family Dept of Chemical Engineering and Materials Science)
More Information: 9.26.2022.Mohammed Hassan (1).pdf
Location: John Stauffer Science Lecture Hall (SLH) - 200
Audiences: Everyone Is Invited
Contact: Anthony Tritto