Observation of the c6h7 radical in an argon matrix using matrix isolation infrared spectroscopy

Amicangelo, Jay C.

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https://hdl.handle.net/2142/107391 Copy

Description

Title

Observation of the c6h7 radical in an argon matrix using matrix isolation infrared spectroscopy

Author(s)

Amicangelo, Jay C.

Contributor(s)

• Orwat, Nicole
• Su, Yen Jui
• Oslosky, Jacob
• Totleben, Lia

Issue Date

2020-06-24

Keyword(s)

Mini-symposium: Spectroscopy with Undergraduates

Abstract

The cyclohexadienyl radical (\chem{C_6H_7}) was observed in a low temperature argon matrix with matrix isolation infrared spectroscopy. The \chem{C_6H_7} radical was produced from the reaction of H atoms with benzene (\chem{C_6H_6}) in the argon matrices. The H atoms were produced by vacuum ultraviolet (VUV) photolysis of \chem{H_2S}, which was co-deposited with the \chem{C_6H_6} in the argon matrices. The most intense peak of the \chem{C_6H_7} radical was observed at 621.0 \wn, with several other weaker peaks observed at 865.9, 910.9, 961.2, 973.7, 1290.3, 1390.2, 1394.9, 1425.9, 2758.7, and 2781.3 \wn. The experiments were performed with various concentrations of \chem{H_2S} and \chem{C_6H_6} and at deposition temperatures of 10 K, 15 K, and 20 K. The largest yield of the \chem{C_6H_7} radical was for VUV photolysis co-deposition of 1:200 \chem{H_2S}:Ar with 1:200 \chem{C_6H_6}:Ar at 15 K. The identification and assignment of the \chem{C_6H_7} radical peaks was accomplished by comparisons to spectra without VUV photolysis, the \chem{H_2S} and \chem{C_6H_6} monomer spectra both with and without VUV photolysis, filtered (400 – 900 nm) Hg-Xe lamp photolysis, and 35 K annealing spectra. Experiments were also performed in which H atoms were reacted with \chem{C_6D_6} producing the \chem{C_6D_6H} radical, with peaks observed at 460.0, 747.8, 759.3, 830.0, 1245.6, 1246.7, and 2791.9/2797.0 \wn. Quantum chemistry calculations for the \chem{C_6H_7} radical were also performed using density functional theory at the B3LYP/aug-cc-pVTZ level to obtain the theoretical structure and theoretical infrared spectrum to support the assignments. The peaks of the \chem{C_6H_7} radical observed in argon matrices are in good agreement with the values reported in xenon matrices\footnote{V.~I.~Feldman, F.~F.~Sukhov, E.~A.~Logacheva, A.~Y.~Orlov, I.~V.~Tyulpina, and D.~A.~Tyurin, Chem.~Phys.~Lett.~\underline{437}, 207 (2007)} and $para$-hydrogen matrices\footnote{M.~Bahou, Y.~J.~Wu, and Y.~P.~Lee, J.~Chem.~Phys.~\underline{136}, 154304 (2012)}.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

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http://hdl.handle.net/2142/107391

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Copyright 2020 is held by the Author(s)

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