Photoelectron spectroscopy of the negative ion SeO−

Coe, James V.; Snodgrass, J. T.; Freidhoff, C. B.; McHugh, K. M.; Bowen, Kit H.

doi:10.1063/1.450608

Cited by 94 publications

(56 citation statements)

References 32 publications

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“…In one case, they were produced with a nozzle-ion source and their photoelectron spectra measured with a continuous anion photoelectron apparatus. 45 In the other case, the anions were generated with a photoinduced electron emission source, and their photoelectron spectra were measured with a pulsed anion photoelectron apparatus. 46 In both instruments, anion photoelectron spectroscopy was conducted by crossing a mass-selected beam of negative ions with a fixed-frequency photon beam and then energy analyzing the resultant photodetached electrons.…”

Section: Experimental Methodsmentioning

confidence: 99%

“…In this type of anion photoelectron spectrometer, the ion source and all of the other components operate continuously. 45 The ion source was a biased (−500 V), supersonic expansion nozzle-ion source in which the acetoacetic acid sample was placed inside its stagnation chamber. There, due to the warming of the source by the adjacent hot filament, some of the sample evaporated and was expanded through a 25 μm diameter nozzle orifice into ∼10 −4 Torr vacuum along with argon gas which was maintained at a pressure of 1−2 atm in the source's stagnation chamber.…”

Section: Experimental Methodsmentioning

confidence: 99%

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Importance of Time Scale and Local Environment in Electron-Driven Proton Transfer. The Anion of Acetoacetic Acid

et al. 2015

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Anion photoelectron spectroscopy (PES) and electron energy-loss spectroscopy (EELS) probe different regions of the anionic potential energy surface. These complementary techniques provided information about anionic states of acetoacetic acid (AA). Electronic structure calculations facilitated the identification of the most stable tautomers and conformers for both neutral and anionic AA and determined their relative stabilities and excess electron binding energies. The most stable conformers of the neutral keto and enol tautomers differ by less than 1 kcal/mol in terms of electronic energies corrected for zero-point vibrations. Thermal effects favor these conformers of the keto tautomer, which do not support an intramolecular hydrogen bond between the keto and the carboxylic groups. The valence anion displays a distinct minimum which results from proton transfer from the carboxylic to the keto group; thus, we name it an ol structure. The minimum is characterized by a short intramolecular hydrogen bond, a significant electron vertical detachment energy of 2.38 eV, but a modest adiabatic electron affinity of 0.33 eV. The valence anion was identified in the anion PES experiments, and the measured electron vertical detachment energy of 2.30 eV is in good agreement with our computational prediction. We conclude that binding an excess electron in a π* valence orbital changes the localization of a proton in the fully relaxed structure of the AA − anion. The results of EELS experiments do not provide evidence for an ultrarapid proton transfer in the lowest π* resonance of AA − , which would be capable of competing with electron autodetachment. This observation is consistent with our computational results, indicating that major gas-phase conformers and tautomers of neutral AA do not support the intramolecular hydrogen bond that would facilitate ultrarapid proton transfer and formation of the ol valence anion. This is confirmed by our vibrational EELS spectrum. Anions formed by vertical electron attachment to dominant neutrals undergo electron autodetachment with or without vibrational excitations but are unable to relax to the ol structure on a time scale fast enough to compete with autodetachment.

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Section: Experimental Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

Importance of Time Scale and Local Environment in Electron-Driven Proton Transfer. The Anion of Acetoacetic Acid

et al. 2015

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“…All photoelectron spectra reported here were recorded with 2.540 eV photons and calibrated against the photoelectron spectrum of O − [15,16]. Our apparatus has been described previously [17].…”

Section: Experimental and Computational Methodsmentioning

confidence: 99%

Electrophilic properties of common MALDI matrix molecules

Lippa¹,

Eustis²,

Wang³

et al. 2007

International Journal of Mass Spectrometry

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“…Our negative ion photoelectron spectrometer has been described elsewhere. 30 Anions were formed in our supersonic expansion source. There, the mixture of indole and water was heated to approximately 70…”

Section: Methodsmentioning

confidence: 99%