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Sensitivity of nonlinear photoionization to resonance substructure in collective excitation.

Mazza T, Karamatskou A, Ilchen M, Bakhtiarzadeh S, Rafipoor AJ, O'Keeffe P, Kelly TJ, Walsh N, Costello JT, Meyer M, Santra R - Nat Commun (2015)

Bottom Line: Resonant photoionization of atomic xenon was chosen as a case study.The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance.Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

View Article: PubMed Central - PubMed

Affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg, Germany.

ABSTRACT
Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

No MeSH data available.


Related in: MedlinePlus

Electronic level scheme and emission spectrum.Electron spectrum from XUV-ionized xenon atoms, recorded at hν=105 eV with a FEL irradiance of (6±2) × 1012 W cm−2, is shown along with the energy level scheme for the xenon orbitals involved in the ionization processes. The spectrum includes features coming from electron emission caused by different processes represented by arrows: 1-photon direct emission (black), Auger emission (green) and 2-photon direct emission (red). In the low-KE region (KE <50 eV) the spectrum is dominated by the contribution from the 4d (1-photon) photoemission and by the subsequent Auger decays involving the 5s and the 5p shells. The small features at KE between 80 and 100 eV arise from the 1-photon photoemission from 5s and 5p shells. The high-energy feature is assigned to the 2-photon photoemission from the 4d shell.
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f2: Electronic level scheme and emission spectrum.Electron spectrum from XUV-ionized xenon atoms, recorded at hν=105 eV with a FEL irradiance of (6±2) × 1012 W cm−2, is shown along with the energy level scheme for the xenon orbitals involved in the ionization processes. The spectrum includes features coming from electron emission caused by different processes represented by arrows: 1-photon direct emission (black), Auger emission (green) and 2-photon direct emission (red). In the low-KE region (KE <50 eV) the spectrum is dominated by the contribution from the 4d (1-photon) photoemission and by the subsequent Auger decays involving the 5s and the 5p shells. The small features at KE between 80 and 100 eV arise from the 1-photon photoemission from 5s and 5p shells. The high-energy feature is assigned to the 2-photon photoemission from the 4d shell.

Mentions: Electron spectra (Fig. 2) were collected under different intensity conditions. The spectra include features caused by 1-photon direct emission from the 5p, 5s and 4d shells as well as from NOO Auger decay25. At higher kinetic energies, the 2-photon ionization from the 4d shell is observed in a spectral feature that resembles in shape the 4d (1-photon) emission lines and is separated from them by exactly the energy of one photon.


Sensitivity of nonlinear photoionization to resonance substructure in collective excitation.

Mazza T, Karamatskou A, Ilchen M, Bakhtiarzadeh S, Rafipoor AJ, O'Keeffe P, Kelly TJ, Walsh N, Costello JT, Meyer M, Santra R - Nat Commun (2015)

Electronic level scheme and emission spectrum.Electron spectrum from XUV-ionized xenon atoms, recorded at hν=105 eV with a FEL irradiance of (6±2) × 1012 W cm−2, is shown along with the energy level scheme for the xenon orbitals involved in the ionization processes. The spectrum includes features coming from electron emission caused by different processes represented by arrows: 1-photon direct emission (black), Auger emission (green) and 2-photon direct emission (red). In the low-KE region (KE <50 eV) the spectrum is dominated by the contribution from the 4d (1-photon) photoemission and by the subsequent Auger decays involving the 5s and the 5p shells. The small features at KE between 80 and 100 eV arise from the 1-photon photoemission from 5s and 5p shells. The high-energy feature is assigned to the 2-photon photoemission from the 4d shell.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4403373&req=5

f2: Electronic level scheme and emission spectrum.Electron spectrum from XUV-ionized xenon atoms, recorded at hν=105 eV with a FEL irradiance of (6±2) × 1012 W cm−2, is shown along with the energy level scheme for the xenon orbitals involved in the ionization processes. The spectrum includes features coming from electron emission caused by different processes represented by arrows: 1-photon direct emission (black), Auger emission (green) and 2-photon direct emission (red). In the low-KE region (KE <50 eV) the spectrum is dominated by the contribution from the 4d (1-photon) photoemission and by the subsequent Auger decays involving the 5s and the 5p shells. The small features at KE between 80 and 100 eV arise from the 1-photon photoemission from 5s and 5p shells. The high-energy feature is assigned to the 2-photon photoemission from the 4d shell.
Mentions: Electron spectra (Fig. 2) were collected under different intensity conditions. The spectra include features caused by 1-photon direct emission from the 5p, 5s and 4d shells as well as from NOO Auger decay25. At higher kinetic energies, the 2-photon ionization from the 4d shell is observed in a spectral feature that resembles in shape the 4d (1-photon) emission lines and is separated from them by exactly the energy of one photon.

Bottom Line: Resonant photoionization of atomic xenon was chosen as a case study.The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance.Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

View Article: PubMed Central - PubMed

Affiliation: European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg, Germany.

ABSTRACT
Collective behaviour is a characteristic feature in many-body systems, important for developments in fields such as magnetism, superconductivity, photonics and electronics. Recently, there has been increasing interest in the optically nonlinear response of collective excitations. Here we demonstrate how the nonlinear interaction of a many-body system with intense XUV radiation can be used as an effective probe for characterizing otherwise unresolved features of its collective response. Resonant photoionization of atomic xenon was chosen as a case study. The excellent agreement between experiment and theory strongly supports the prediction that two distinct poles underlie the giant dipole resonance. Our results pave the way towards a deeper understanding of collective behaviour in atoms, molecules and solid-state systems using nonlinear spectroscopic techniques enabled by modern short-wavelength light sources.

No MeSH data available.


Related in: MedlinePlus