Multiple differential cross sections for the ionization from the 1B1 orbital of liquid water molecule by fast electron impact

M. L. DE SANCTIS; O. A. FOJÓN; R. VUILLEUMIER; C. R. STIA; M. F. POLITIS

Valparaíso, Chile

Congreso; V Encuentro Sudamericano de Colisiones Inelásticas en la Materia; 2010

Universidad Técnica Federico Santa María

We study the single ionization of water molecules in liquid phase by electron impact at high impact energies. We compute multiple differential cross sections within a simple first order model. We employ wavefunctions obtained through a Wannier orbital formalism in order to represent de initial molecular state of the liquid phase. In particular, we consider coplanar geometries in which the incident, scattered and ejected electrons lie in the same plane. Moreover, we analyze asymmetric kinematic conditions for the scattered and ejected electrons (ejected energies of some eV). By means of an approximate static potential, we obtain an estimation of the influence of the passive electrons of the molecule (those not ionized) on the ionization process. We compute MDCS for the 1B1 orbital of the water molecule as a function of the ejection angle at definite scattering angle, incident and ejected energies, and for fixed orientations of the molecule. It is observed that MDCS depend strongly on the orientation of the molecule. As experimental results of MDCS at fixed molecular orientations for liquid water are not available, we compare our theoretical predictions with other theoretical ones obtained for water molecules in gas phase. In addition, as molecules are randomly oriented in experiments with water vapor, we also present MDCS averaged over all molecular orientations. The main physical features of the experiments (such as binary and recoil peaks) are similar to the ones observed in our results.