Violation of the Franck-Condon Principle due to Recoil Effects in High Energy Molecular Core-Level Photoionization

Kukk, E.; Ueda, Kiyoshi; Hergenhahn, U.; Liu, X.-J.; Prümper, G.; Yoshida, Hiroaki; Tamenori, Y.; Makochekanwa, Casten; Tanaka, Takahiro; Kitajima, M.; Tanaka, Hiroshi

doi:10.1103/physrevlett.95.133001

Cited by 135 publications

(83 citation statements)

References 16 publications

(18 reference statements)

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“…40 A similar effect has been observed for CH 4 for the v = 1 and v = 2 components. 47 Figure 2 shows that vibrational excitations due to recoil effects are much less pronounced for BF 3 than for CF 4 (and CH 4 47 ). As can be seen, BF 3 photoionization leads to a large progression of vibrational levels in its symmetric stretching mode.…”

Section: Resultsmentioning

confidence: 99%

Intramolecular photoelectron diffraction in the gas phase

Ueda

Miron

Plésiat

et al. 2013

The Journal of Chemical Physics

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We report unambiguous experimental and theoretical evidence of intramolecular photoelectron diffraction in the collective vibrational excitation that accompanies high-energy photoionization of gas-phase CF 4 , BF 3 , and CH 4 from the 1s orbital of the central atom. We show that the ratios between vibrationally resolved photoionization cross sections (v-ratios) exhibit pronounced oscillations as a function of photon energy, which is the fingerprint of electron diffraction by the surrounding atomic centers. This interpretation is supported by the excellent agreement between first-principles static-exchange and time-dependent density functional theory calculations and high resolution measurements, as well as by qualitative agreement at high energies with a model in which atomic displacements are treated to first order of perturbation theory. The latter model allows us to rationalize the results for all the v-ratios in terms of a generalized v-ratio, which contains information on the structure of the above three molecules and the corresponding molecular cations. A fit of the measured v-ratios to a simple formula based on this model suggests that the method could be used to obtain structural information of both neutral and ionic molecular species.

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Section: Resultsmentioning

confidence: 99%

Intramolecular photoelectron diffraction in the gas phase

Ueda

Miron

Plésiat

et al. 2013

The Journal of Chemical Physics

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“…This is partly due to the need for high kinetic-energy resolution in combination with high photon energy (that of x rays) but also to the fact that emission of a fast electron is accompanied by recoil of the residual cation [28], thus leading to a redistribution of the available energy even on symmetry-forbidden vibrational modes. As shown by Kukk et al [28], the recoil of CH + 4 ions leads to excitation of the asymmetric stretching and bending vibrations, which superimpose to the dominant symmetric stretching vibrational components. As a result, the apparent v ratios increase almost linearly with photon energy, thus hiding the underlying diffraction.…”

Section: Introductionmentioning

confidence: 99%

“…The specific example we consider here is vibrationally resolved C(1s) photoionization of CH 4 , a molecule for which there is a vast literature [26][27][28][29], but no evidence of diffraction has been reported so far. This is partly due to the need for high kinetic-energy resolution in combination with high photon energy (that of x rays) but also to the fact that emission of a fast electron is accompanied by recoil of the residual cation [28], thus leading to a redistribution of the available energy even on symmetry-forbidden vibrational modes.…”

Section: Introductionmentioning

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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“…For molecules, such recoil effects have been described for the first time in the pioneering work by Domcke and Cederbaum 9 . They are, however, rather weak in the soft X-ray regime up to about 1 keV in energy and have been observed only in recent years in photoelectron spectra: the first observation of vibrational recoil was observed by Kukk et al 10 in the methane molecule. Later on, this effect was more clearly observed in the tetrafluoro methane molecule CF 4 (ref.…”

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confidence: 99%

Atomic Auger Doppler effects upon emission of fast photoelectrons

et al. 2014

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Studies of photoemission processes induced by hard X-rays including production of energetic electrons have become feasible due to recent substantial improvement of instrumentation. Novel dynamical phenomena have become possible to investigate in this new regime. Here we show a significant change in Auger emission following 1s photoionization of neon, which we attribute to the recoil of the Ne ion induced by the emission of a fast photoelectron. Because of the preferential motion of the ionized Ne atoms along two opposite directions, an Auger Doppler shift is revealed, which manifests itself as a gradual broadening and doubling of the Auger spectral features. This Auger Doppler effect should be a general phenomenon in high-energy photoemission of both isolated atoms and molecules, which will have to be taken into account in studies of other recoil effects such as vibrational or rotational recoil in molecules, and may also have consequences in measurements in solids.

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Violation of the Franck-Condon Principle due to Recoil Effects in High Energy Molecular Core-Level Photoionization

Cited by 135 publications

References 16 publications

Intramolecular photoelectron diffraction in the gas phase

Intramolecular photoelectron diffraction in the gas phase

Intramolecular electron diffraction in vibrationally resolvedK-shell photoionization of methane

Atomic Auger Doppler effects upon emission of fast photoelectrons

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