  Here we report the first evidence for a reversible phase change in an
ethanethiol ice prepared under astrochemical conditions. InfraRed (IR)
spectroscopy was used to monitor the morphology of the ice using the S-H
stretching vibration, a characteristic vibration of thiol molecules. The
deposited sample was able to switch between amorphous and crystalline phases
repeatedly under temperature cycles between 10 K and 130 K with subsequent loss
of molecules in every phase change. Such an effect is dependent upon the
original thickness of the ice. Further work on quantitative analysis is to be
carried out in due course whereas here we are reporting the first results
obtained.
