Electron scattering cross sections for diazene (N[formula omitted]H[formula omitted]) and hydrazine (N[formula omitted]H[formula omitted

Abstract

In this work, a computational study on electron interactions with diazene (N2H2) and hydrazine (N2H4) was performed; two conformations of N2H2 (E–N2H2 and Z–N2H2) were considered. Differential cross sections (DCS), integral cross sections (ICS), and momentum transfer cross sections (MTCS) for elastic scattering as well as total cross sections (TCS) and total absorption cross sections (TACS) were explored at incident energies from 0.1 to 500 eV. A molecular complex optical potential approach combined with Padé approximants was used for describing the electron–molecule collision dynamics and solving the scattering equations. Marked differences were noticed when the DCS for elastic electron–Z–N2H2 scattering were compared to the corresponding results for electron–E–N2H2 (particularly at low incident energies and small angles), a behavior which was assigned to the existence of a permanent dipole moment in the case of the Z–N2H2 molecule; results regarding N2H4 were found to be considerably more similar to those determined for Z–N2H2. In terms of ICS and MTCS, results obtained for E–N2H2 presented a first peak at 1.15 eV (originating from the 2Bg continuum symmetry and being related to the π∗ resonance arising from the nitrogen-nitrogen bond) and another at around 10 eV. These peaks can be related to the −N=N− moiety and to the existence of the N−H bonds, respectively. Interestingly, no peaks were clearly observed in Z–N2H2 ICS and MTCS while only the peak at around 10 eV was (barely) seen in the MTCS of N2H4, even without employing the Born-closure procedure. Hence, conformation plays a major role in probing the resonances for the N2H2 molecule, being the strong dipole moments responsible for masking the structures in the case of Z–N2H2 (as well as eventual additional peaks in N2H4). TACS results were found to be (practically) the same for both conformations of N2H2 at the energy range probed, being systematically lower than N2H4 TACS. In addition, the maxima of absorption was found at 70 eV for N2H4, which is slightly shifted when compared to the maxima probed for E–N2H2 and Z–N2H2 (observed at 80 eV).