Study of the CH<sub>3</sub>CHOH Radical with Ultraviolet Photoelectron Spectroscopy

Dyke, John M.; Groves, Adam; Lee, E. P. F.; Niavaran, M. Hadi Zamanpour

doi:10.1021/jp961302j

Cited by 29 publications

(28 citation statements)

References 23 publications

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“…Note also that the acetyl radical tends to dissociate into CO and CH 3 8, thus preventing any autoionization even if the energetics allowed it. A recent G2 calculation of acetyl 9 has given a VIE of 8.39 eV, which is close to the experimental value, and an AIE of 6.66 eV.…”

Section: Resultssupporting

confidence: 76%

Generation of the C₂H₃O⁺ ion in reactions of O(³P) with 2‐butyne

Metropoulos

2005

Int J of Quantum Chemistry

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ABSTRACT:We investigated the feasibility of formation of the C 2 H 3 O ϩ chemiion during collisions of O( 3 P) with the CH 3 C (ã 4 A 2 ), CH 2 CH (ã 4 AЉ), CH 3 C (X 2 AЉ), and CH 2 CH (X 2 AЈ) radicals, which are possible intermediates in the oxidation of 2-butyne. We determined the C-O bond dissociation energies and the ionization energies of the neutral C 2 H 3 O species as well as the C-O bond dissociation energies of C 2 H 3 O ϩ . We conclude that the CH 3 C (ã 4 A 2 ) radical is the most probable precursor of the chemiion, in agreement with experimental evidence.

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Section: Resultssupporting

confidence: 76%

Generation of the C₂H₃O⁺ ion in reactions of O(³P) with 2‐butyne

Metropoulos

2005

Int J of Quantum Chemistry

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“…Experimentally-determined values are shown in bold; calculated values are shown in italics. b Hydrogen-atom abstraction reaction efficiency = second-order hydrogen-atom abstraction rate constant/collision rate constant (k exp /k coll ). c Reference 71. d Reference 61. e Reference 53. f Reference 72. g Reference 62. h Reference 22. i Reference 74. j Average of the BDE values for cis- and trans- proline; reference 75. k Reference 73. …”

Section: Figures and Tablesmentioning

confidence: 99%

Correlation of Hydrogen-Atom Abstraction Reaction Efficiencies for Aryl Radicals with their Vertical Electron Affinities and the Vertical Ionization Energies of the Hydrogen-Atom Donors

2008

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The factors that control the reactivities of aryl radicals toward hydrogen-atom donors were studied by using a dual-cell Fourier-transform ion cyclotron resonance mass spectrometer (FT – ICR). Hydrogen-atom abstraction reaction efficiencies for two substrates, cyclohexane and isopropanol, were measured for twenty-three structurally different, positively-charged aryl radicals, which included dehydrobenzenes, dehydronaphthalenes, dehydropyridines, and dehydro(iso)quinolines. A logarithmic correlation was found between the hydrogen-atom abstraction reaction efficiencies and the (calculated) vertical electron affinities (EA) of the aryl radicals. Transition state energies calculated for three of the aryl radicals with isopropanol were found to correlate linearly with their (calculated) EAs. No correlation was found between the hydrogen-atom abstraction reaction efficiencies and the (calculated) enthalpy changes for the reactions. Measurement of the reaction efficiencies for the reactions of several different hydrogen-atom donors with a few selected aryl radicals revealed a logarithmic correlation between the hydrogen-atom abstraction reaction efficiencies and the vertical ionization energies (IE) of the hydrogen-atom donors, but not the lowest homolytic X – H (X = heavy atom) bond dissociation energies of the hydrogen-atom donors. Examination of the hydrogen-atom abstraction reactions of twenty-nine different aryl radicals and eighteen different hydrogen-atom donors showed that the reaction efficiency increases (logarithmically) as the difference between the IE of the hydrogen-atom donor and the EA of the aryl radical decreases. This dependence is likely to result from the increasing polarization, and concomitant stabilization, of the transition state as the energy difference between the neutral and ionic reactants decreases. Thus, the hydrogen-atom abstraction reaction efficiency for an aryl radical can be “tuned” by structural changes that influence either the vertical EA of the aryl radical or the vertical IE of the hydrogen atom donor.

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“…Anastasi et al 31,32 observed broad absorption spectra for both radicals in the range of 300-210 nm using a pulse radiolysis/kinetic absorption technique, although their assignment of the CH 2 CH 2 OH spectrum is called into question by the results reported here. The ionization potential of CH 3 CHOH was measured to be <6.85 eV by photoionization mass spectrometry; 27 a more precise value of 6.64 ( 0.03 eV was recently obtained by Dyke et al 33 using photoelectron spectroscopy.…”

Section: Introductionmentioning

confidence: 97%

Photodissociation Dynamics of the Ethoxy Radical (C₂H₅O)

2000

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Photodissociation of the ethoxy (C 2 H 5 O) radical is investigated using photofragment translational spectroscopy. The ethoxy radical is generated by photodetachment of C 2 H 5 O -and subsequently dissociated by photon absorption in the range of 270-220 nm; no dissociation is seen at higher wavelengths. The photofragment yield (PFY) spectrum is structureless but exhibits abrupt increases in intensity at 260 and 225 nm. The product mass distribution shows that C 2 H 5 O dissociates into the vinyl radical (C 2 H 3 ) and H 2 O throughout the entire absorption band. We propose that these products are formed by isomerization and dissociation on electronically excited surfaces rather than by internal conversion to the ground state. The translational energy P(E T ) distributions for this channel are largely insensitive to photon energy. However, at the two highest photon energies (5.51 and 5.96 eV), a new feature appears at E T e 0.3 eV, which is assigned as production of an excited state of C 2 H 3 .

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Study of the CH₃CHOH Radical with Ultraviolet Photoelectron Spectroscopy

Cited by 29 publications

References 23 publications

Generation of the C₂H₃O⁺ ion in reactions of O(³P) with 2‐butyne

Generation of the C₂H₃O⁺ ion in reactions of O(³P) with 2‐butyne

Correlation of Hydrogen-Atom Abstraction Reaction Efficiencies for Aryl Radicals with their Vertical Electron Affinities and the Vertical Ionization Energies of the Hydrogen-Atom Donors

Photodissociation Dynamics of the Ethoxy Radical (C₂H₅O)

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Study of the CH3CHOH Radical with Ultraviolet Photoelectron Spectroscopy

Cited by 29 publications

References 23 publications

Generation of the C2H3O+ ion in reactions of O(3P) with 2‐butyne

Generation of the C2H3O+ ion in reactions of O(3P) with 2‐butyne

Correlation of Hydrogen-Atom Abstraction Reaction Efficiencies for Aryl Radicals with their Vertical Electron Affinities and the Vertical Ionization Energies of the Hydrogen-Atom Donors

Photodissociation Dynamics of the Ethoxy Radical (C2H5O)

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Study of the CH₃CHOH Radical with Ultraviolet Photoelectron Spectroscopy

Generation of the C₂H₃O⁺ ion in reactions of O(³P) with 2‐butyne

Generation of the C₂H₃O⁺ ion in reactions of O(³P) with 2‐butyne

Photodissociation Dynamics of the Ethoxy Radical (C₂H₅O)