High-resolution C 1<i>s</i>photoelectron spectra of methane

Köppe, H. M.; Itchkawitz, B. S.; Kilcoyne, A. L. D.; Feldhaus, J.; Kempgens, B.; Kivimäki, A.; Neeb, M.; Bradshaw, A. M.

doi:10.1103/physreva.53.4120

Cited by 68 publications

(44 citation statements)

References 39 publications

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“…Figure 1 shows the photoelectron-Auger-electron coincidence map (bottom left panel) for C 1s photoionization and subsequent KV V Auger decay. Integration along the Auger electron axis results in the photoelectron spectrum (PES), which is shown in the upper panel of the figure and is very similar to previously published high-resolution photoelectron spectra; see, e.g., [32][33][34]. In this spectrum, the vibrational substates v = 0, 1, and 2 are clearly visible at kinetic energies around 13.3, 12.9, and 12.5 eV, respectively.…”

Section: Methodssupporting

confidence: 65%

Probing dissociative molecular dications by mapping vibrational wave functions

et al. 2011

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We present high-resolution photoelectron-Auger-electron coincidence spectra of methane (CH 4 ). Since the vibrational structure in the photoelectron spectrum is resolved, the Auger spectra corresponding to different vibrational levels can be separated. The seven final states of CH 2+ 4 are either dissociative or metastable, but in any case are populated in a repulsive part of their potential-energy curve via the Auger decay. The Auger line shapes can therefore be obtained by mapping the vibrational wave functions of the core-hole state into energy space. We have implemented this connection in the data analysis. By simultaneously fitting the different Auger spectra, detailed information on the energies of the dicationic states and their repulsive potential-energy curves is derived.

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Section: Methodssupporting

confidence: 65%

Probing dissociative molecular dications by mapping vibrational wave functions

et al. 2011

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“…The final state losses lead to the equidistant shift of C 1 and C 2 to apparent higher binding energies. Analogous vibrational fine structure in the C 1s photoelectron region has been observed previously in gas phase spectroscopic measurements of methane, 29 and has been reported for ethylidyne ͑C 2 H 3 ͒ chemisorbed on Rh͑111͒, 30 methoxy ͑CH 3 O͒ on Cu͑100͒, 31 and for ethylene ͑C 2 H 4 ͒ and acetylene ͑C 2 H 2 ͒ on Si͑001͒. 6 The value for h C-H = 0.38͑0.01͒ eV deduced for methyl-terminated Si compares well with the excitation energies of 0.385͑0.010͒ eV ͑Ref.…”

Section: Methodssupporting

confidence: 51%

Chemical and electronic characterization of methyl-terminated Si(111) surfaces by high-resolution synchrotron photoelectron spectroscopy

et al. 2005

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The chemical state, electronic properties, and geometric structure of methyl-terminated Si͑111͒ surfaces prepared using a two-step chlorination/alkylation process were investigated using high-resolution synchrotron photoelectron spectroscopy and low-energy electron diffraction methods. The electron diffraction data indicated that the methylated Si surfaces maintained a ͑1 ϫ 1͒ structure, where the dangling bonds of the silicon surface atoms were terminated by methyl groups. The surfaces were stable to annealing at 720 K. The high degree of ordering was reflected in a well-resolved vibrational fine structure of the carbon 1s photoelectron emission, with the fine structure arising from the excitation of C-H stretching vibrations having h = 0.38± 0.01 eV. The carbon-bonded surface Si atoms exhibited a well-defined x-ray photoelectron signal having a core level shift of 0.30± 0.01 eV relative to bulk Si. Electronically, the Si surface was close to the flat-band condition. The methyl termination produced a surface dipole of −0.4 eV. Surface states related to CH 3 and Si-C bonding orbitals were identified at binding energies of 7.7 and 5.4 eV, respectively. Nearly ideal passivation of Si͑111͒ surfaces can thus be achieved by methyl termination using the two-step chlorination/ alkylation process.

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“…[42]. We have used the same fitting procedure to reanalyze previous measurements performed at SPring8 (Japan).…”

Section: Experimental Methodsmentioning

confidence: 99%

Intramolecular electron diffraction in vibrationally resolvedK-shell photoionization of methane

et al. 2012

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Current techniques based on x-ray or electron diffraction are successfully employed for structure determination in condensed matter but are sometimes limited when applied to low density media such as the gas phase. Here we show that vibrationally resolved photoelectron spectroscopy based on x rays generated by third generation synchrotron light sources can be used to infer the structure of isolated molecules in a simple and efficient way. In particular, we show that vibrational ratios obtained from inner shell C 1s photoelectron spectroscopy of isolated methane molecules exhibit pronounced oscillations that are the fingerprints of electron diffraction by the surrounding atomic centers, thus providing the necessary information for the determination of the molecular geometry.

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High-resolution C 1sphotoelectron spectra of methane

Cited by 68 publications

References 39 publications

Probing dissociative molecular dications by mapping vibrational wave functions

Probing dissociative molecular dications by mapping vibrational wave functions

Chemical and electronic characterization of methyl-terminated Si(111) surfaces by high-resolution synchrotron photoelectron spectroscopy

Intramolecular electron diffraction in vibrationally resolvedK-shell photoionization of methane

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