J. A. Noble, E. Congiu, F. Dulieu, H. J. Fraser
The desorption characteristics of molecules on interstellar dust grains are
important for modelling the behaviour of molecules in icy mantles and,
critically, in describing the solid-gas interface. In this study, a series of
laboratory experiments exploring the desorption of three small molecules from
three astrophysically relevant surfaces are presented. The desorption of CO, O2
and CO2 at both sub-monolayer and multilayer coverages was investigated from
non-porous water, crystalline water and silicate surfaces. Experimental data
was modelled using the Polanyi-Wigner equation to produce a mathematical
description of the desorption of each molecular species from each type of
surface, uniquely describing both the monolayer and multilayer desorption in a
single combined model. The implications of desorption behaviour over
astrophysically relevant timescales are discussed.
View original:
http://arxiv.org/abs/1112.2162
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