  In a recent article, Schild et al. present what they call an alternative
approach to the determination of mean free paths of electron scattering in
liquid water. This by no means new approach is based on a very simplistic two
channel model of electron scattering with only one fully elastic and one fully
inelastic (total loss) channel. The parameterization consists of an elastic
cross section, its angular dependence (DCS), and a cross section for electron
loss by inelastic scattering. The two cross sections (or the equivalent MFPs)
are determined from fits to experimental data (EALs and measured anisotropy
parameters). The elastic DCS is calculated ab initio for various cluster
models. Furthermore, they claim to find elastic and inelastic mean free paths
that are much shorter than those for amorphous ice. We find that there are a
number of issues both with the approach of the authors and with the comparison
of their results with the literature. As outlined in the comment, the reported
values for elastic and inelastic mean free paths are questionable and
conclusions regarding the difference between electron scattering in liquid
water and amorphous ice are invalid.
