University of Illinois Urbana-Champaign

Electronic Ground And Excited State Spectral Diffusion Of A Photocatalyst

Kiefer, Laura M.

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TH10_Abstract.pdf
TH10_Abstract.txt
TH10_Presentation.pptx

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https://hdl.handle.net/2142/51195

Description

Title
Electronic Ground And Excited State Spectral Diffusion Of A Photocatalyst
Author(s)
Kiefer, Laura M.
Contributor(s)
  • Kubarych, Kevin J
  • King, John T.
Issue Date
2014-06-17
Keyword(s)
Mini-symposium: Spectroscopy in Kinetics and Dynamics
Date of Ingest
  • 2014-09-17T16:56:25Z
  • 2015-04-14T18:37:56Z
Abstract
\chem{Re(bpy)(CO)_3Cl} is a well studied \chem{CO_2} reduction catalyst, known for its ability as both a photosensitizer and a catalyst with a high quantum yield and product selectivity. The catalysis reaction is initiated by a 400 nm excitation, followed by an intersystem crossing (ISC) and re-equilibration in the lowest triplet state. We utilize the quasi-equilibrium nature of this long-lived triplet metal-to-ligand charge-transfer ($^{3}$MLCT) state to completely characterize the solvent dynamics using the technique of transient two-dimensional infrared (t-2DIR) spectroscopy to extract observables such as the frequency-frequency correlation function (FFCF), an equilibrium function. The electronic ground state solvent dynamics are characterized using equilibrium two-dimensional infrared spectroscopy (2D IR). Our technique allows us to independently observe the solvent dynamics of different electronic states and compare them. In this study, three carbonyl stretching modes were utilized to probe both the intramolecular and solvent environments in each electronic state. In the electronic ground state, the totally symmetric mode exhibits pure homogeneous broadening and a lack of spectral dynamics, while the two other modes have similar FFCF decay times of $\sim$ 1.5 ps. In the $^{3}$MLCT, however, all three modes experience similar spectral dynamics and have a FFCF decay time of $\sim$ 4.5 ps, three times slower than in the electronic ground state. Our technique allows us to directly observe the differences in spectral dynamics of the ground and excited electronic states and allows us to attribute the differences to specific origins such as solvent-solute coupling and molecular flexibility.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
English
Permalink
http://hdl.handle.net/2142/51195
DOI
https://doi.org/10.15278/isms.2014.TH10
Copyright and License Information
Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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Abstracts & Presentations - 2014 International Symposium on Molecular Spectroscopy PRIMARY