Auger electron–ion coincidence experiment on nitrogen molecule excited by electron impact

Abstract

The first Auger electron–ion coincidence experiment on the nitrogen molecule excited by electron impact is described. The kinetic energy releases of the N++ and the N+ fragments in the 43–72 eV binding energy range have been measured. The experimental results are compared with previous experimental data obtained by using synchrotron radiation and theoretical predictions.

Formation, stability and dissociation dynamics of ${{\rm{N}}}_{2}{}^{{\rm{n}}+}$ cations (n= 1 − 2) in 3.5 keV e−-N2collisions studied using the energy resolved electron–ion coincidence technique

“…In fact, the N 2+ fragments that originated from process (5) given in table 1 are expected to have low kinetic energy, as we observe in our experiment; this is because the B.E. of the initial + N 2 2 dissociative states (55 eV-68 eV) are very close to the E th =53.9 eV of that process [12,18]. The low intensity of the peaks in this region of the spectra coupled with our poor energy resolution prohibits any quantitative assignment of the configuration of the fragmentation products from our data.…”

“…With such an intrinsic energy resolution, the presence of a DC field applied in the interaction region neither produces an appreciable change in the energy resolution of the electrons measured by the CMA nor affects the shape and intensity of the electron energy spectra. The KER values of the fragment ions for the dissociation pathways can be estimated using the relation [18]:…”

“…A common feature to be noted in these figures is that there is a presence of + N , 2 + N 2 2 and N 2+ ions with their Table 1. Adiabatic threshold energies (E th ) for different decay channels with respect to the ground state of N 2 [14,18]. N b 2 ions correspond to those which initially move away from the detector after their birth and turn around to reach the detector.…”

“…The results reported here were obtained using energetic electrons of 3.5 keV as an excitation source; nevertheless, a number of such measurements have also been performed with a synchrotron radiation source [10][11][12][13][14] and with ions [15,16]. Alberti et al [17] and Fainelli et al [18,19] have performed the coincidence measurements between emitted electrons of known energies and fragmented ions, including electron-ion-ion coincidence using a 4.0 keV electron impact on N 2 . In their experiments, the fragmentation patterns were recorded and the kinetic energy of the fragments was determined for the specific energy of emitted electrons.…”

New results on core excited N2O obtained by electron–ion coincidence spectroscopya)

“…One way to approach this ''state to state'' photochemistry is to perform coincidence experiments between energy analyzed electrons and fragment ions, as has been recently developed. [7][8][9][10][11][12] However, such experiments remain very difficult, especially in the field of molecules for the following reasons:…”