Energy dependence of the Penning ionization electron spectrum of Ne* (3P2,0)+Kr

Brunetti, Brunetto Giovanni; Candori, Pietro; Falcinelli, Stefano; Lescop, Benoît; Liuti, G.; Pirani, Fernando; Vecchiocattivi, Franco

doi:10.1140/epjd/e2005-00312-5

Cited by 35 publications

(33 citation statements)

References 31 publications

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“…This can be easily achieved because the microwave discharge produces not only metastable atoms but also many He(I) and Ne(I) photons, having an energy comparable to that of metastable atoms. To calibrate the electron transmission efficiency and the electron energy scale, some He * -H2O, H2S, NH3 PIES, and Ne(I)-H2O, H2S, NH3 PES spectra have been measured by exploiting the microwave discharge beam source: in the first case we use for the energy calibration the weak electron signal by He(I) photons of 21.22 eV, whereas in the latter case we record a PES spectrum, using the discharge source in pure neon producing a high intensity of Ne(Iα,β) photons [22,34], essentially of 16.84 and 16.66 eV, respectively, in a α:β ratio of about 5.3, checked by photoelectron spectrometric measurements of Kr atoms [35,36]. By comparison of our measurements with the expected spectrum as obtained from the He(I) radiation by Kimura et al [37], we calibrate the ionization energy scale.…”

Section: Experimental Techniquesmentioning

confidence: 99%

The Possible Role of Penning Ionization Processes in Planetary Atmospheres

2015

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Abstract:In this paper we suggest Penning ionization as an important route of formation for ionic species in upper planetary atmospheres. Our goal is to provide relevant tools to researchers working on kinetic models of atmospheric interest, in order to include Penning ionizations in their calculations as fast processes promoting reactions that cannot be neglected. Ions are extremely important for the transmission of radio and satellite signals, and they govern the chemistry of planetary ionospheres. Molecular ions have also been detected in comet tails. In this paper recent experimental results concerning production of simple ionic species of atmospheric interest are presented and discussed. Such results concern the formation of free ions in collisional ionization of H2O, H2S, and NH3 induced by highly excited species (Penning ionization) as metastable noble gas atoms. The effect of Penning ionization still has not been considered in the modeling of terrestrial and extraterrestrial objects so far, even, though metastable helium is formed by radiative recombination of He + ions with electrons. Because helium is the second most abundant element of the universe, Penning ionization of atomic or molecular species by He * (2 3 S1) is plausibly an active route of ionization in relatively dense environments exposed to cosmic rays. OPEN ACCESSAtmosphere 2015, 6 300

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Section: Experimental Techniquesmentioning

confidence: 99%

The Possible Role of Penning Ionization Processes in Planetary Atmospheres

2015

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“…On the other hand, the importance of carbon dioxide and nitrous oxide are well known in the Earth's atmosphere where both species are important greenhouse gases and N 2 O can participate in ozone depletion [49,50]. Moreover, CO 2 is the main component of the Mars (95.3%) and Venus (96.5%) atmospheres and, together with acetylene molecules, has been detected as a minor component in Titan's atmosphere (2-4 ppm and about 10 ppb, respectively) [51].…”

Section: Resultsmentioning

confidence: 99%

Molecular Dications in Planetary Atmospheric Escape

et al. 2016

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Fundamental properties of multiply charged molecular ions, such as energetics, structure, stability, lifetime and fragmentation dynamics, are relevant to understand and model the behavior of gaseous plasmas as well as ionosphere and astrophysical environments. Experimental determinations of the Kinetic Energy Released (KER) for ions originating from dissociations reactions, induced by Coulomb explosion of doubly charged molecular ions (molecular dications) produced by double photoionization of CO 2 , N 2 O and C 2 H 2 molecules of interest in planetary atmospheres, are reported. The KER measurement as a function of the ultraviolet (UV) photon energy in the range of 28-65 eV was extracted from the electron-ion-ion coincidence spectra obtained by using tunable synchrotron radiation coupled with ion imaging techniques at the ELETTRA Synchrotron Light Laboratory Trieste, Italy. These experiments, coupled with a computational analysis based on a Monte Carlo trajectory simulation, allow assessing the probability of escape for simple ionic species in the upper atmosphere of Mars, Venus and Titan. The measured KER in the case of H + , C + , CH + , CH 2 + , N + , O + , CO + , N 2 + and NO + fragment ions range between 1.0 and 5.5 eV, being large enough to allow these ionic species to participate in the atmospheric escape from such planets into space. In the case of Mars, we suggest a possible explanation for the observed behavior of the O + and CO 2 2+ ion density profiles.

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“…The used experimental set up, described in detail in previous papers [25,30,34] and showed in Fig. 2, basically consists of a metastable hydrogen or rare gas atom beam crossing at right angles an effusive molecular beam.…”

Section: Methodsmentioning

confidence: 99%

“…In general, such a source was employed by using a ≈6 or ≈10 Torr inlet pressure of pure Helium or Neon, respectively. When we use such a device performing Penning ionization experiments with Ne * metastable atoms, we are producing both metastable atoms and a high intensity of Ne(I α,β ) photons, essentially of 73.6 and 74.4 nm wavelength respectively, in a α:β ratio of about 5.3, checked by photoelectron spectrometric measurements of Kr atoms [22,25]. The use of the microwave discharge beam source allows us also to calibrate the electron transmission efficiency and the electron energy scale in our PIES measurements by recording photoionization spectra for the investigated systems and comparing them with data reported in literature [42].…”

Section: Methodsmentioning

confidence: 99%

“…This allows the various systems to be put on a relative scale which can be then normalized by reference to a known cross section such as, in the present case, the Ne * -Ar absolute total ionization cross-section by West et al [43]. For electron energy spectra determinations, a hemispherical electrostatic selector has been used [25,36]. This is located above the beam crossing volume in opposite direction with respect to the quadrupole mass spectrometer.…”

Section: Methodsmentioning

confidence: 99%

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A Theoretical and Computational Approach to a Semi-classical Model for Electron Spectroscopy Calculations in Collisional Autoionization Processes

Falcinelli

Rosi

Pirani

et al. 2016

Computational Science and Its Applications – ICCSA 2016

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Abstract. The analysis of energy spectra of emitted electrons is of great relevance to understand the main characteristics of the potential energy surfaces and of the stereodynamics of the collisional autoionization processes. In this work we analyze the electron kinetic energy spectra obtained in our laboratory in high resolution crossed beam experiments. For such an analysis, a novel semi-classical method is proposed, that assumes ionization events as mostly occurring in the vicinities of the collision turning points. The potential energy driving the system in the relevant configurations of the entrance and exit channels, used in the spectrum simulation, has been formulated by the use of a semi-empirical method. The analysis puts clearly in evidence how different approaches of the metastable atom to the target molecule lead to ions in different electronic states.

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Energy dependence of the Penning ionization electron spectrum of Ne* (3P2,0)+Kr

Cited by 35 publications

References 31 publications

The Possible Role of Penning Ionization Processes in Planetary Atmospheres

The Possible Role of Penning Ionization Processes in Planetary Atmospheres

Molecular Dications in Planetary Atmospheric Escape

A Theoretical and Computational Approach to a Semi-classical Model for Electron Spectroscopy Calculations in Collisional Autoionization Processes

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