Vibronic Emission Spectroscopy Of Benzyl-type Radicals Generated By Corona Discharge

Lee, Sang

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https://hdl.handle.net/2142/51145 Copy

Description

Title

Vibronic Emission Spectroscopy Of Benzyl-type Radicals Generated By Corona Discharge

Author(s)

Lee, Sang

Contributor(s)

• Yoon, Young
• Yi, Eun Hye

Issue Date

2014-06-16

Keyword(s)

Radicals

Abstract

Benzyl radical is a prototypical aromatic free radical and has been the subject of numerous spectroscopic studies. On the other hand, ring-substituted benzyl radicals, benzyl-type radicals, have received less attention due to the difficulties associated with production in corona discharge and analysis of spectra. We report vibronic emission spectra of hetero halogen multi-substituted benzyl radicals generated by corona discharge of corresponding toluene derivatives using a pinhole-type glass nozzle, from which visible vibronic emission spectra were recorded using a long-path monochromator. The spectra show nice features of strongest origin band and a series of vibronic bands in the lower energies originating from the vibrationless D$_1$ state. From the analysis of the spectra observed, we determined the energies of the D$_1$ $\rightarrow$ D$_0$ electronic transition and vibrational mode frequencies in the ground electronic state.\footnote{Y.~W.~Yoon and S.~K.~Lee, \textit{J.~Phys.~Chem.~A} \underline{\textbf{117}}, 2485 (2013).} On the other hand, all substituted benzyl radicals show the origin bands shifted to red region with respect to the parental benzyl radical at 22002 cm$^{-1}$. The shifts of multi-substituted benzyl radicals can be well estimated using the method developed from mono-substituted benzyl radicals as well as the positions of nodal point and mutual orientation of substituents, which could be useful for scientists to set a proper scanning range of their spectrometers for the spectroscopic observation of transient molecules. In this presentation, we will discuss the substituent effect\footnote{Y.~W.~Yoon, S.~Y.~Chae, and S.~K.~Lee, \textit{Chem.~Phys.~Lett.} \underline{\textbf{584}}, 37 (2013).}\footnote{Y.~W.~Yoon and S.~K.~Lee, \textit{Chem.~Phys.~Lett.} \underline{\textbf{570}}, 29 (2013).}on electronic transition energy and the experimental technique developed in this laboratory.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/51145

DOI

https://doi.org/10.15278/isms.2014.MI01

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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