The ionization of water molecules is a relevant reaction in fields such as plasma physics, fusion experiments, astrophysics, and radiobiology. We perform a theoretical study of the simple ionization of liquid and gas-phase molecules via fast-electron impact. We employ a first-order perturbative model and consider asymmetric collisions in a coplanar geometry. The reaction observables, i.e., the cross-sections, are obtained via numerical calculation [1-3]. We compute triple-differential cross-sections for the liquid and the gaseous phases. To describe the bound states of liquid-phase water molecules, we utilize a Wannier orbital formalism [4] . Localized orbitals for individual molecules are generated, which include information regarding their interactions with the surrounding liquid environment. The initial bound state of the molecule in the gas phase is represented by linear combinations of Gaussian functions centered on each atom of the water molecule (this approach provides a representation of the multicenter structure of the molecule). The fast-incident and scattered electrons in the reaction are described by plane waves, whereas the ejected electron at low energy is described by a Coulomb wave.
We compare our predictions with experimental data, theoretical calculations, and previous calculations for liquid-phase water [5,6 and references therein] of triple-differential, double-differential, single-differential, and total cross-sections. We find qualitative agreement with the different data. Although the physical properties of the phases are different, the scarse available results nevertheless show little difference.
References
[1] M.L. de Sanctis et al, J. Phys. B (2012) 45, 045206
[2] M.L. de Sanctis et al, J. Phys. B (2015) 48, 0155201.
[3] M.L. de Sanctis et al, Eur. Phys. J.D (2017) 71, 125
[4] P. Hunt et al, Chem. Phys. Lett. (2003) 376, 68
[5] C. Champion Phys. Med. Biol. 55 (2010) 11–32
[6] Mi-Young Song et al, J. Phys. Chem. (2021) Ref. Data 50 , 023103