Dissociative single and double photoionization with excitation between 37 and 69 eV in N<sub>2</sub>

Ehresmann, A.; Machida, Shinjiro; Kitajima, M.; Ukai, Masatoshi; Kameta, Kosei; Kouchi, Noriyuki; Hatano, Yoshihiko; Shigemasa, E.; Hayaishi, T

doi:10.1088/0953-4075/33/3/316

Cited by 19 publications

(20 citation statements)

References 37 publications

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“…4. The XUV photons populate a superexcited state of the molecular ion, (N 2 + ) * , which can have an internal energy above the double photoionization threshold [24,25]. If there is no IR pulse present in the experiment (or if the delay between the XUV and the IR pulses is long enough), the excited wave packet evolves along the (N 2 + ) * potential energy curve until the internuclear distance is sufficient to energetically allow the autoionization r c IR FIG.…”

Section: A Pump-probe Measurementsmentioning

confidence: 99%

Autoionization and ultrafast relaxation dynamics of highly excited states in N2

et al. 2012

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We have used the velocity-map imaging (VMI) technique to measure autoionization dynamics in molecular nitrogen initiated by a train of attosecond pulses. The pump-probe measurements show clear evidence of a crossing between potential energy curves of the highly excited N 2 + ion and of the N 2 2+ ion. It is found that the autoionization becomes energetically allowed when the two nuclei are still very close (∼ 3Å), in contrast with observations in other diatomic molecules, and that it can be coherently manipulated by a strong femtosecond infrared pulse.

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Section: A Pump-probe Measurementsmentioning

confidence: 99%

Autoionization and ultrafast relaxation dynamics of highly excited states in N2

et al. 2012

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“…14. The decay of the v = 0 state is dominated by optical transitions to the ground state. The (0,0) and (0,1) bands emit photons that are characterized by wavelengths 1587 and 1594 Å, respectively (e.g, Ehresmann et al 2000). Higher vibrational levels decay by predissociation.…”

Section: The Auger Effect and Double Valence Shell Ionization In Molementioning

confidence: 99%

Energy Deposition in Planetary Atmospheres by Charged Particles and Solar Photons

2008

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We discuss here the energy deposition of solar FUV, EUV and X-ray photons, energetic auroral particles, and pickup ions. Photons and the photoelectrons that they produce may interact with thermospheric neutral species producing dissociation, ionization, excitation, and heating. The interaction of X-rays or keV electrons with atmospheric neutrals may produce core-ionized species, which may decay by the production of characteristic X-rays or Auger electrons. Energetic particles may precipitate into the atmosphere, and their collisions with atmospheric particles also produce ionization, excitation, and heating, and auroral emissions. Auroral energetic particles, like photoelectrons, interact with the atmospheric species through discrete collisions that produce ionization, excitation, and heating of the ambient electron population. Auroral particles are, however, not restricted to the sunlit regions. They originate outside the atmosphere and are more energetic than photoelectrons, especially at magnetized planets. The spectroscopic analysis of auroral emissions is discussed here, along with its relevance to precipitating particle diagnostics. Atmospheres can also be modified by the energy deposited by the incident pickup ions with energies of eV's to MeV's; these particles may be of solar wind origin, or from a magnetospheric plasma. When the modeling of the energy deposition of the plasma is calculated, the subsequent modeling of the atmospheric processes, such as chemistry, emission, and the fate of hot recoil particles produced is roughly independent of the exciting radiation. However, calculating the spatial distribution of the energy deposition versus depth into the atmosphere produced by an incident plasma is much more complex than is the calculation of the solar excitation profile. Here, the nature of the energy deposition processes by the incident plasma are described as is the fate of the hot recoil particles produced by exothermic chemistry and by knock-on collisions by the incident ions.

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“…Results of many experimental investigations of N 2 prior to 1998 have been summarized by Gallagher et al [1988], and in the book by Berkowitz [2002]. Recent photoionization investigations include Ehresmann et al [2000] and Nicholas et al [2003] on dissociative ionization, Marquette et al [1999] and Kugeler et al [2004] on the coupling between valence‐ionized and core‐excited states. The break‐down of the Frank‐Condon approximation in rotationally and vibrationally resolved partial ionization cross sections, caused by non‐adiabatic coupling and autoionization, has also been examined by Poliakoff et al [1995], Rao et al [1996], Öhrwall et al [1998, 1999], Riu et al [2001], Rathbone et al [2004], and Bolognesi et al [2004].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of electron impact excitation of N₂ X ¹Σ_g⁺(0) into the N₂⁺ X ²Σ_g⁺(v), A ²Π_u(v), and B ²Σ_u⁺(v) states

Shemansky

Liu

2005

J. Geophys. Res.

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Published experimental integrated electric dipole photoionization oscillator strengths (fij) have been applied to the determination of absolute electron impact excitation cross sections of the N2 X 1Σg+(0) state into the N2+ X 2Σg+(v), A 2Πu(v), and B 2Σu+(v) states. The required relative electron impact cross section shape functions from threshold to energy values, limited by the imposition of relativistic effects at the high end, are established in this work by extracting accurate analytic functions from a critical review of extensive published experimental results. The cross sections examined here are important benchmarks used in establishing absolute values for critical rate processes in aeronomy. The determination of the absolute cross sections using the derived fij is accomplished through the physical relationship to a modified Born approximation analytic function that defines the electron impact shape functions. The zero order term of the analytic function is established in value relative to the remaining terms through shape analysis of the experimental electron impact results. The value of fij fixes the absolute value of the zero order term, determining the cross sections over the entire electron impact energy range. It is argued that this methodology is the most accurate approach at this time because of the existence of the intrinsically more accurate photometrically dermined fij. The critical quantities in atmospheric process applications are the branching ratios of excitation into the N2+ X 2Σg+, A 2Πu, and B 2Σu+ states. The N2+ (X 2Σg+, A 2Πu, B 2Σu+) partitioning within the total ionization cross section has been a source of disagreement in the literature, in spite of the fact that substantial effort has been expended in establishing acceptably accurate values. The present work establishes accurate cross sections for these states over the entire practical energy range required for research in atmospheric N2 physical chemistry. The accuracy of the results obtained here are verified by consistency with the most reliably established past experimental electron impact cross sections, in agreement with the independently established total N2+ cross section. We provide analytic collision strengths for the vibrational levels of the N2+ X 2Σg+, A 2Πu, and B 2Σu+ states, allowing establishment of rate coefficients for the system, at an estimated error ≤±8%.

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Dissociative single and double photoionization with excitation between 37 and 69 eV in N₂

Cited by 19 publications

References 37 publications

Autoionization and ultrafast relaxation dynamics of highly excited states in N2

Autoionization and ultrafast relaxation dynamics of highly excited states in N2

Energy Deposition in Planetary Atmospheres by Charged Particles and Solar Photons

Evaluation of electron impact excitation of N₂ X ¹Σ_g⁺(0) into the N₂⁺ X ²Σ_g⁺(v), A ²Π_u(v), and B ²Σ_u⁺(v) states

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Dissociative single and double photoionization with excitation between 37 and 69 eV in N2

Cited by 19 publications

References 37 publications

Autoionization and ultrafast relaxation dynamics of highly excited states in N2

Autoionization and ultrafast relaxation dynamics of highly excited states in N2

Energy Deposition in Planetary Atmospheres by Charged Particles and Solar Photons

Evaluation of electron impact excitation of N2 X 1Σg+(0) into the N2+ X 2Σg+(v), A 2Πu(v), and B 2Σu+(v) states

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Dissociative single and double photoionization with excitation between 37 and 69 eV in N₂

Evaluation of electron impact excitation of N₂ X ¹Σ_g⁺(0) into the N₂⁺ X ²Σ_g⁺(v), A ²Π_u(v), and B ²Σ_u⁺(v) states