An exploratory study has been made of the energy loss of a low energy
electron incident on a thin dielectric film while it is travelling out
side of the dielectric. Quantal theory is used to represent the electr
on while the polarisation propagator of the dielectric is constructed
from local theory for water. Numerical results using this theory have
been compared with experimental data from thin, solid, amorphous H2O f
ilms. Although not strictly comparable, since the media considered are
not identical, it is believed that under some circumstances such aloo
f losses could represent a significant part of the measured loss distr
ibutions, particularly at the lower energies employed.