Pictures of unbound molecular electrons, including shape-resonant states. Eigenchannel contour maps

Loomba, D.; Wallace, Scott; Dill, Dan; Dehmer, Joseph L.

doi:10.1063/1.442622

Cited by 74 publications

(31 citation statements)

References 16 publications

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“…Remaining in the case of a single channel perturbed by a short-range potential, a generalized eigenstate ψ E of the full Hamiltonian can also be normalized so as to be real across the whole space [10], in which case it differs from the reference state in the asymptotic region by a radial phase shift, …”

Section: Photoionization Time Delaymentioning

confidence: 99%

Control of photoemission delay in resonant two-photon transitions

et al. 2017

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The photoelectron emission time delay τ associated with one-photon absorption, which coincides with half the Wigner delay τ W experienced by an electron scattered off the ionic potential, is a fundamental descriptor of the photoelectric effect. Although it is hard to access directly from experiment, it is possible to infer it from the time delay of two-photon transitions, τ (2) , measured with attosecond pump-probe schemes, provided that the contribution of the probe stage can be factored out. In the absence of resonances, τ can be expressed as the energy derivative of the one-photon ionization amplitude phase, τ = ∂ E arg D Eg , and, to a good approximation, τ = τ (2) − τ cc , where τ cc is associated with the dipole transition between Coulomb functions. Here we show that, in the presence of a resonance, the correspondence between τ and ∂ E arg D Eg is lost. Furthermore, while τ (2) can still be written as the energy derivative of the two-photon ionization amplitude phase,Eg , it does not have any scattering counterpart. Indeed, τ (2) can be much larger than the lifetime of an intermediate resonance in the two-photon process or more negative than the lower bound imposed on scattering delays by causality. Finally, we show that τ (2) is controlled by the frequency of the probe pulse, ω IR , so that by varying ω IR , it is possible to radically alter the photoelectron group delay.

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Section: Photoionization Time Delaymentioning

confidence: 99%

Control of photoemission delay in resonant two-photon transitions

et al. 2017

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“…15,19 From this transformation one also obtains the eigenphases ␣ for each eigenchannel. The eigenphase sum, 20 sum = ͚ ␣ ␣ , is the multichannel analog of the single-channel central potential scattering phase shift encountered in formal scattering theory.…”

Section: -3mentioning

confidence: 99%

“…2͒ that this resonance is substantially carried by just a single eigenchannel. Figure 3 shows contour plots of this selected resonant eigenchannel 19 which are made in a plane 0.25 Å above the molecular plane ͑since the latter is a nodal plane for b 2g symmetry͒ at the indicated photoelectron kinetic energies selected below, above, and at the shape resonant energy. Along with the corresponding surface representations, these show the strong localization of the continuum function around the six-membered ring and the enhanced amplitude that develops at resonance.…”

Section: -3mentioning

confidence: 99%

An unusual π* shape resonance in the near-threshold photoionization of S1 para-difluorobenzene

Bellm

Davies

Whiteside

et al. 2005

The Journal of Chemical Physics

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Previously reported dramatic changes in photoelectron angular distributions ͑PADs͒ as a function of photoelectron kinetic energy following the ionization of S 1 p-difluorobenzene are shown to be explained by a shape resonance in the b 2g symmetry continuum. The characteristics of this resonance are clearly demonstrated by a theoretical multiple-scattering treatment of the photoionization dynamics. New experimental data are presented which demonstrate an apparent insensitivity of the PADs to both vibrational motion and prepared molecular alignment, however, the calculations suggest that strong alignment effects may nevertheless be recognized in the detail of the comparison with experimental data. The apparent, but unexpected, indifference to vibrational excitation is rationalized by considering the nature of the resonance. The correlation of this shape resonance in the continuum with a virtual * antibonding orbital is considered. Because this orbital is characteristic of the benzene ring, the existence of similar resonances in related substituted benzenes is discussed.

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“…[1][2][3] However, processes in the ionization continuum frequently span a wide spectral range. For example, Cooper minima 4 -8 and shape resonances [9][10][11][12][13][14][15][16] typically extend over a range of 10-50 eV, and it is hence desirable to study rotational distributions over a comparable range. Unfortunately, rotationally resolved photoelectron experiments are typically limited to the near-threshold region [17][18][19][20][21][22][23][24][25][26][27] ͑although recent progress has resulted in partially rotationally resolved photoelectron data over a significant range 28,29 ͒.…”

Section: Introductionmentioning

confidence: 99%

Rotationally resolved photoionization: Influence of the 4σ→kσ shape resonance on CO+(B 2Σ+) rotational distributions

Farquar

Miller

Poliakoff

et al. 2001

The Journal of Chemical Physics

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We present experimental and theoretical results on rotational distributions of CO ϩ (B 2 ⌺ ϩ ) photoions. Rotational distributions were determined for both the v ϩ ϭ0 and v ϩ ϭ1 vibrational levels following photoionization of cold (T 0 Ϸ9 K) neutral CO target molecules. Data were generated using dispersed ionic fluorescence over a wide range of photoelectron kinetic energies, 0рE k р120 eV, which allows one to interrogate the ionization dynamics. This wide spectral coverage permits illustrative comparisons with theory, and calculated spectra are presented to interpret the data. In particular, the comparison between theory and experiment serves to identify the strong continuum resonant enhancement at h exc Ϸ35 eV in the lϭ3 partial wave of the 4→k ionization channel, as this feature has profound effects on the ion rotational distributions over a wide range of energy. Second, there are differences between the rotational substructure for the v ϩ ϭ0 and v ϩ ϭ1 vibrational levels. All of the experimentally observed features and trends are reproduced by theory, and the consequences of these comparisons are discussed.

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Pictures of unbound molecular electrons, including shape-resonant states. Eigenchannel contour maps

Cited by 74 publications

References 16 publications

Control of photoemission delay in resonant two-photon transitions

Control of photoemission delay in resonant two-photon transitions

An unusual π* shape resonance in the near-threshold photoionization of S1 para-difluorobenzene

Rotationally resolved photoionization: Influence of the 4σ→kσ shape resonance on CO+(B 2Σ+) rotational distributions

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