Electron Spectroscopy and Mass Spectrometric Study of Penning Ionization of N2O and H2O molecules

In the study here presented, we report on the results of an experimental investigation based on the measurement of the collision energy dependence, in the thermal energy range, of: i) the cross sections for each one of the possible ionic product channels in the Ne*-N2O and Ne*-H2O systems; ii) the PIES for He* and Ne* autoionizing collisions with the same molecular targets. In our experiment different observables are obtained, for each system, in the same apparatus, with identical experimental conditions, allowing for a direct integration of these information, in order to obtain a complete picture of the dynamics of the studied reactions. By mass spectrometry we determined total and partial cross sections for each product ions, as a function of collision energy, while, by using a hemispherical electron energy analyzer, we measured the energy spectrum of product electrons for collisions at different translational energies. The total and partial ionization cross sections have been measured in the collision energy range between 0.03 and 0.2 eV and the electron energy spectra have been obtained at four different collision energies: 0.055, 0.124, 0.184, and 0.441 eV. The analysis of the data exploits both a semiempirical evaluation of the intermolecular interaction between the two neutral partners and the features of the N2O and H2O molecular orbitals involved in the exchange mechanism, which is assumed to be the most responsible one for the collisional autoionization.