Photoionization cross sections for the production of the doubly charged ion N2+ from N-2 have been measured by means of synchrotron radiation in the photon energy range from 50 to 110 eV. The appearance energy for N2+ has been determined as 55.2 +/- 0.2 eV, i.e., about 1.3 eV higher than the spectroscopic dissociation limit leading to the charge asymmetric dissociation channel N2+(P-2)+N(S-4) at 53.9 eV. The onset of a second threshold at 59.9 +/- 0.2 eV is detected and the energy dependence of photoion intensities near the threshold regions is interpreted in terms of the Wannier theory. The production of the N2+ dication is discussed in terms of direct and indirect mechanisms for dissociative charge asymmetric photoionization and by comparison with the potential energy curves of the intermediate N-2(2+) dication. Experimental evidences for the opening of the Coulomb explosion channel N2++N+ at high photon energies are provided by measuring the kinetic energy release spectra of N2+ fragments at selected photon energies. (c) 2007 American Institute of Physics.

Dissociative double photoionization of N-2 using synchrotron radiation: Appearance energy of the N2+ dication

De Simone M;Coreno M
2007

Abstract

Photoionization cross sections for the production of the doubly charged ion N2+ from N-2 have been measured by means of synchrotron radiation in the photon energy range from 50 to 110 eV. The appearance energy for N2+ has been determined as 55.2 +/- 0.2 eV, i.e., about 1.3 eV higher than the spectroscopic dissociation limit leading to the charge asymmetric dissociation channel N2+(P-2)+N(S-4) at 53.9 eV. The onset of a second threshold at 59.9 +/- 0.2 eV is detected and the energy dependence of photoion intensities near the threshold regions is interpreted in terms of the Wannier theory. The production of the N2+ dication is discussed in terms of direct and indirect mechanisms for dissociative charge asymmetric photoionization and by comparison with the potential energy curves of the intermediate N-2(2+) dication. Experimental evidences for the opening of the Coulomb explosion channel N2++N+ at high photon energies are provided by measuring the kinetic energy release spectra of N2+ fragments at selected photon energies. (c) 2007 American Institute of Physics.
2007
Istituto di Nanotecnologia - NANOTEC
INFM
Istituto Officina dei Materiali - IOM -
ELECTRON-IMPACT IONIZATION
CROSS-SECTIONS
ANGULAR-DISTRIBUTIONS
DIATOMIC-MOLECULES
COULOMB EXPLOSION
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/143622
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