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Optical Control of Living Cells Electrical Activity by Conjugated Polymers
Published on: January 28, 2016
Optical control of electrons during electron transfer.
I B Martini1, E R Barthel, B J Schwartz
1Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA 90095-1569, USA.
Science (New York, N.Y.)
|July 21, 2001
Summary
Femtosecond laser pulses control electron transfer reactions. Exciting electrons in immediate contact pairs halts back transfer, while exciting those in solvent-separated pairs has mixed effects on sodium anion production.
Area of Science:
- Chemical Dynamics
- Physical Chemistry
- Photochemistry
Background:
- Electron transfer reactions in solution are fundamental to many chemical processes.
- Controlling these reactions is crucial for developing new chemical transformations and technologies.
- The charge transfer to solvent (CTTS) reaction provides a model system for studying electron dynamics.
Purpose of the Study:
- To investigate the use of sequential femtosecond laser pulses to control electron transfer dynamics.
- To elucidate the role of different contact pair configurations in the CTTS reaction of sodide in tetrahydrofuran.
- To understand how targeted electron excitation influences back electron transfer rates.
Main Methods:
- Utilizing a sequence of three femtosecond laser pulses to initiate, manipulate, and monitor the CTTS reaction.
- Generating sodide (Na-) in tetrahydrofuran and initiating the CTTS reaction with an initial pulse.
- Employing a second pulse to excite electrons within immediate or solvent-separated contact pairs (Na0:solvated electron).
- Monitoring Na- production via back electron transfer using a third pulse.
Main Results:
- The initial pulse successfully initiated the CTTS reaction, forming Na0:solvated electron contact pairs.
- Excitation of electrons in immediate contact pairs effectively suppressed back electron transfer, preventing Na- reformation.
- Excitation of electrons in solvent-separated pairs exhibited a dual effect, both enhancing and hindering back electron transfer.
- The specific configuration of the contact pair significantly influences the outcome of the electron excitation process.
Conclusions:
- Sequential femtosecond laser pulses offer a precise method for controlling electron transfer dynamics in solution.
- The spatial arrangement of the electron and cation within contact pairs dictates the response to external optical excitation.
- This study demonstrates a pathway to selectively control reaction outcomes by manipulating intermediate electronic states.
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