A Monte-Carlo study of sub-keV electron transport in water: the influence of the condensed phase

We explore the influence of condensed phase in various single-collision and slowing-down distributions of low-energy (sub-keV) electron tracks in water (i.e. vapor versus liquid phase at the same density). A unified methodology for both phases has been developed and implemented in our Monte-Carlo code based on elements of the Born and Bethe theories which are used to establish cross-sections for inelastic electronic scattering, the main mechanism of energy loss in the present study. The linear dielectric response theory was used for the valence shells of the liquid phase implemented by Born-corrections at low energies. By using experimental optical data as input, various many-body effects, such as, polarisation, collective excitations and correlation, are, for the most part, automatically accounted for. Monte-Carlo calculations of the spatial pattern of energy distribution, as well as, the clustering properties of collision events in full slowing-down electron tracks have been performed for both the vapor and liquid phases of water. The degree in which various model assumptions pertaining to the condensed-phase influence the above distributions is examined.