"MOLECULAR PROPERTIES OF THE ﾀNTI-AROMATIC"" SPECIES CYCLOPENTADIENONE, C5H5=0"

Ellison, Barney

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Description

Title

"MOLECULAR PROPERTIES OF THE ﾀNTI-AROMATIC"" SPECIES CYCLOPENTADIENONE, C5H5=0"

Author(s)

Ellison, Barney

Contributor(s)

• Hemberger, Patrick
• Zwier, Timothy S.
• Ahmed, Musahid
• Stanton, John F.
• Daily, John W.
• Ormond, Thomas

Issue Date

25-Jun-15

Keyword(s)

Mini-symposium: Accelerator-Based Spectroscopy

Abstract

begin{wrapfigure}{l}{0pt} includegraphics[scale=0.18]{Barney_figure.eps} end{wrapfigure}A common intermediate in the high temperature combustion of benzene is cyclopentadienone, C$_{5}$H$_{4}$=O. Cyclopentadienone is considered to be an �anti-aromatic� molecule. It is certainly a metastable species; samples persist at LN$_{2}$ temperatures but dimerize upon warming to -$80^{circ}$C. It is of great interest to physically characterize this �anti-aromatic� species. The microwave spectrum, the infrared spectrum, the ionization energy, and the electron affinity of cyclopentadienone have been measured. Flash pyrolysis of o�phenylene sulfite (C$_{6}$H$_{4}$O$_{2}$SO) provides molecular beams of C$_{5}$H$_{4}$=O entrained in a rare gas carrier. The beams are interrogated with time-of-flight photoionization mass spectrometry, confirming the clean, intense production of C$_{5}$H$_{4}$=O. a) Chirped-pulse Fourier transform microwave spectroscopy and CCSD(T) electronic structure calculations have combined to determinefootnote{Kidwell textit{et al.} J. Phys. Chem. Letts. 2201 (2014)} the r$_{e}$ molecular structure of C$_{5}$H$_{4}$=O. b) Guided by CCSD(T) electronic structure calculations, the matrix infrared absorbance spectrum of C$_{5}$H$_{4}$=O isolated in a 4 K neon matrix has been usedfootnote{Ormond textit{et al.} J. Phys. Chem. A textbf{118}, 708 (2014)} to assign 20 of the 24 fundamental vibrational frequencies. c) Imaging photoelectron photoion coincidence (iPEPICO) spectrafootnote{Ormond textit{et al.} Mol. Phys. textbf{in press} (2015)} of cyclopentadienone establishes the ionization energy, IE(C$_{5}$H$_{4}$=O), to be 9.41 $pm$ 0.01 eV. d) Prof. A. Sanov�s groupfootnote{Khuseynov textit{et al.} J. Phys. Chem. A textbf{118}, 6965 (2014)} has reported the electron affinity, EA(C$_{5}$H$_{4}$=O), to be 1.06 $pm$ 0.01 eV.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

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