In: Physical Review A, 2011, vol. 83, no. 5, p. 052701
Absolute vibrational excitation cross sections were measured for diacetylene (1,3-butadiyne). The selectivity of vibrational excitation reveals detailed information about the shape resonances. Excitation of the C≡C stretch and of double quanta of the C-H bend vibrations reveals a ²Πu resonance at 1 eV (autodetachment width ~30 meV) and a ²Πg resonance at 6.2 eV...
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In: Physical Chemistry Chemical Physics, 2008, vol. 10, p. 5232 - 5237
A difference was observed in the reactivity of alcohols and ethers toward free electrons. Whereas the lowest core-excited state of the negative ion—a ²(n,3s²) Feshbach resonance—of the alcohols readily dissociates by losing a hydrogen atom, ethers show no observable signal from this resonance. This difference in reactivity has a parallel in the anomalous shapes and energies of the...
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In: Physical Review A, 2008, vol. 77, no. 4, p. 040701
Absolute cross sections for the production of the two astronomy-relevant negative ions H−C≡C⁻ and H−C≡C−C≡C⁻ by dissociative electron attachment to acetylene C₂H₂ and diacetylene C₄H₂ were measured (with a ±25% error bar). Acetylene yielded the C₂H⁻ ion at an electron energy of 2.95 eV with a cross section of 3.6±0.9 pm² and also the C₂⁻ ion at 8.1 eV...
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In: Physical Chemistry Chemical Physics, 2008, vol. 10, p. 1507-1511
Dissociative electron attachment (DEA) to diethyl ether yielded primarily the C₂H₅O⁻ ion, with a strong Feshbach resonance band at 9.1 eV and a weaker shape resonance band at 3.89 eV. Very similar spectra were obtained for dibutyl ether, with C₄H₉O⁻ bands at 8.0 and 3.6 eV. Some of these primary ions subsequently lost H₂ and yielded weaker signals of the C₂H₃O⁻ and...
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In: Physical Chemistry Chemical Physics, 2007, vol. 9, p. 3163-3173
We studied dissociative electron attachment to a series of compounds with one or two hydroxyl groups. For the monoalcohols we found, apart from the known fragmentations in the 6–12 eV range proceeding via Feshbach resonances, also new weaker processes at lower energies, around 3 eV. They have a steep onset at the dissociation threshold and show a dramatic D/H isotope effect. We assigned...
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