Main properties of multiply charged molecular ions (energetics, structure, stability, lifetime and fragmentation dynamics) are relevant to know and to model the behavior of gaseous plasmas, planetary ionospheres, and astrophysical environments. Experimental measurements of the kinetic energy released of fragment ions produced by the Coulomb explosion of molecular dications (doubly charged molecular species) originating by double photoionization of CO2 molecules, are reported and discussed. The kinetic energy released, as a function of the UV photon energy in the range of 34–50 eV, is extracted from the electron–ion–ion coincidence spectra recorded by using tunable synchrotron radiation coupled with ion imaging techniques at the GasPhase beam line of ELETTRA Synchrotron Light Laboratory Trieste, Italy. This kind of experiment allows assessing the probability of escape for simple ionic species in the ionosphere of Mars and Titan. The kinetic energy released, measured in the case of O+ and CO+ fragment ions, are ranging between 1.0–5.0 and 0.4–3.0 eV, respectively. These values are large enough to allow such ionic species in participating in the atmospheric escape from Mars (only O+ ions) and Titan (both O+ and CO+ ions) into space. In the case of Mars, we suggest a possible rationalization for the observed behavior of the O+ and CO2+2 ion density profiles by Viking 1 lander and Mariner 6 spacecraft.

The Escape of O+ and CO+ Ions from Mars and Titan Atmospheres by Coulomb Explosion of CO2+2 Molecular Dications

FALCINELLI, Stefano
2017

Abstract

Main properties of multiply charged molecular ions (energetics, structure, stability, lifetime and fragmentation dynamics) are relevant to know and to model the behavior of gaseous plasmas, planetary ionospheres, and astrophysical environments. Experimental measurements of the kinetic energy released of fragment ions produced by the Coulomb explosion of molecular dications (doubly charged molecular species) originating by double photoionization of CO2 molecules, are reported and discussed. The kinetic energy released, as a function of the UV photon energy in the range of 34–50 eV, is extracted from the electron–ion–ion coincidence spectra recorded by using tunable synchrotron radiation coupled with ion imaging techniques at the GasPhase beam line of ELETTRA Synchrotron Light Laboratory Trieste, Italy. This kind of experiment allows assessing the probability of escape for simple ionic species in the ionosphere of Mars and Titan. The kinetic energy released, measured in the case of O+ and CO+ fragment ions, are ranging between 1.0–5.0 and 0.4–3.0 eV, respectively. These values are large enough to allow such ionic species in participating in the atmospheric escape from Mars (only O+ ions) and Titan (both O+ and CO+ ions) into space. In the case of Mars, we suggest a possible rationalization for the observed behavior of the O+ and CO2+2 ion density profiles by Viking 1 lander and Mariner 6 spacecraft.
2017
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/1399690
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 9
  • ???jsp.display-item.citation.isi??? 9
social impact