Simplification of photoelectron spectra of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>in intense laser fields

Helm, H.; Dyer, Mark J.; Bissantz, H.

doi:10.1103/physrevlett.67.1234

Cited by 33 publications

(14 citation statements)

References 14 publications

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“…They found that dissociative ionization was an important channel for photon absorption from the double-welled E,F 'X+ state, and that competition between ionization, dissociation, and dissociative ionization was dependent on the rovibrational level excited in the intermediate state. Finally, Helm, Dyer, and Bissantz have recently performed measurements of both electron and proton kinetic energies at wavelengths only slightly longer than ours (308 nm + A,~320 nm) [34]; they observe very-lowkinetic-energy protons, which is consistent with our dissociative ionization assignment.…”

Section: B 2885-nm Resultssupporting

confidence: 89%

High-intensity multiphoton ionization ofH2

Allendorf

Szöke

1991

Phys. Rev. A

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A tunable, high-intensity picosecond-dye-laser system has been employed with electron energy analysis to investigate the dynamics of (3+ 1) resonance-enhanced multiphoton ionization via various vibrational levels of the B 'X"and C 'Il"electronic states in H2. At the intensities studied [(0.2 -6) X 10" W/cm ], we find evidence for production of molecular ions in various vibrational levels; at the lower intensities the population distribution of final vibrational states varies with wavelength in a manner consistent with resonant enhancement at the three-photon level, followed by ionization into a vibrational level of H2+ roughly predictable by a Franck-Condon analysis of ionization out of the C state. At higher intensities, there is a shift to increased population of lower vibrational states of H2+, consistent with an ac Stark shift of the correspondingly lower vibrational levels of the C state into resonance with the three-photon energy of the laser. Clear evidence of direct dissociation of H2 followed by single-photon ionization of the excited H atom is observed as well. Above-threshold ionization of these two processes occurs readily. We also find that dissociative ionization is an increasingly important ionization pathway as the wavelength is increased. Finally, we see evidence of a fourth ionization pathway, which we tentatively assign to photoionization into a transient bound state created by the avoided crossing of the first repulsive electronic state of H2,~2po. ", n), with the single-photon-dressed ground state of Hz+, isos, n +1).

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Section: B 2885-nm Resultssupporting

confidence: 89%

High-intensity multiphoton ionization ofH2

Allendorf

Szöke

1991

Phys. Rev. A

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“…The major complication, of course, is the additional degrees of freedom associated with nuclear motion, which makes the full quantum mechanical theoretical treatment still a most challenging problem even for the simple neutral hydrogen molecule [14]. Photoelectron spectroscopy in the subtunneling intensity regime indicates that Freeman-type resonances with Rydberg states as well as higher valence states play a crucial role also for molecules [15][16][17][18][19]. As for atoms, such Rydberg resonances appear in the electron spectrum as sharp peaks located at E γ -E b , where E γ is the photon energy and E b is the electronic binding energy of the Rydberg state, independent of the light intensity [16,17,19].…”

Section: Introductionmentioning

confidence: 99%

“…Photoelectron spectroscopy in the subtunneling intensity regime indicates that Freeman-type resonances with Rydberg states as well as higher valence states play a crucial role also for molecules [15][16][17][18][19]. As for atoms, such Rydberg resonances appear in the electron spectrum as sharp peaks located at E γ -E b , where E γ is the photon energy and E b is the electronic binding energy of the Rydberg state, independent of the light intensity [16,17,19]. Particular molecular phenomena that occur because of the inherent atomic multicenter nature, in addition to alignment and orientation effects [20][21][22], include molecular bond softening and hardening, enhanced ionization, above-threshold dissociation, and Coulomb explosion [12].…”

Section: Introductionmentioning

confidence: 99%

Strong-field photoionization ofO2at intermediate light intensity

et al. 2010

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We investigated by electron spectroscopy the strong-field multiphoton ionization of O 2 molecules with ultrashort laser pulses in the intensity range between the multiphoton and tunneling regimes. The ionization proceeds by at least three different mechanisms, in addition to the eight-and nine-photon nonresonant pathways. Transient multiphoton resonances with vibrational Rydberg levels give rise to direct Freeman-type peaks with sublaser linewidth and spin-orbit splitting. Some resonance levels actually become populated and yield extremely narrow lines because of postpulse vibrational autoionization. When the lowest photon order resonance channel for the Rydberg states is closed, a third contribution becomes dominant with a main peak at 0.4 eV that shares its main properties with the recently discovered universal low-energy structure in the electron spectra of atoms and molecules [C. I. Blaga et al., Nat. Phys. 5, 335 (2009); W. Quan et al., Phys. Rev. Lett. 103, 093001 (2009)]. The variation of the Freeman resonance spectrum with the laser peak intensity is well correlated with the vibronic Franck-Condon factors for the overlap of the intermediate Rydberg state with the O 2 ground state. Accordingly, the Freeman peaks could be unambiguously assigned to individual vibronic multiphoton resonances, and the disappearance of the Freeman resonances at a certain laser intensity could be explained. The population of the autoionizing Rydberg states could be assigned similarly to such vibronic resonances.

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“…[1][2][3][4][5][6] It is considerably more complicated compared to atoms due to their multicenter nature, which introduces additional vibrational and rotational degrees of freedom, and a detailed understanding of the ionization mechanism remains unsettled. A powerful approach in studying the dynamic processes is using velocity map imaging where simultaneous measurement of the photoelectron kinetic energy and angular distributions facilitates the identification and classification of ionization mechanisms.…”

Section: Introductionmentioning

confidence: 99%

“…[10][11][12][13][14][15] Previous studies provide evidence that strong-field ionization of molecules shares many of the characteristics with those of atoms, 1,2 and indeed the two mechanisms have been observed by previous experimental results for molecules. [1][2][3] N2 is one of the two major ingredients of the atmosphere, and its MPI dynamics in intense femtosecond laser fields has been studies extensively. Gibson ) were significant at 616 nm by using conventional photoelectron spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond Photoelectron Imaging of N₂at 410 nm

Guo¹,

Wei²,

Lu³

et al. 2010

Bulletin of the Korean Chemical Society

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We experimentally measure the kinetic energy and angular distributions of photoelectrons of N2 as a function of 410 nm femtosecond laser intensity by using velocity map imaging technique. The strong-field multiphoton ionization of molecules shares many of the characteristics with those of atoms. Electron kinetic energies are nearly independent of laser intensities. The independence suggests that the electron peaks in the photoelectron spectrum actually result from a twostep process, indicative of the occurrence of real population in the intermediate states. The relative amplitudes of electron peaks indicate that in the two-step process, nonresonant population transfer dominates for low intensities, while resonant population transfer dominates for higher intensities.

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Simplification of photoelectron spectra ofH2in intense laser fields

Cited by 33 publications

References 14 publications

High-intensity multiphoton ionization ofH2

High-intensity multiphoton ionization ofH2

Strong-field photoionization ofO2at intermediate light intensity

Femtosecond Photoelectron Imaging of N₂at 410 nm

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Simplification of photoelectron spectra ofH2in intense laser fields

Cited by 33 publications

References 14 publications

High-intensity multiphoton ionization ofH2

High-intensity multiphoton ionization ofH2

Strong-field photoionization ofO2at intermediate light intensity

Femtosecond Photoelectron Imaging of N2at 410 nm

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Product

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Femtosecond Photoelectron Imaging of N₂at 410 nm