Experimental study of the formation of molecular hydrogen and carbon dioxide on dust grain analogues

In the past five years, we have conducted laboratory studies of the formation of key molecules on dust grain analogues in astrophysically relevant conditions. After a description of the apparatus and of the experimental methods, we report on the application of such methods to the resolution of two astrophysical problems that have been left unsolved: (1) The determination of the efficiency and mechanism of formation of molecular hydrogen on different types of interstellar dust grains (silicates, carbonaceous material and ices) and (2) The elucidation of the mechanisms of formation of CO2 in dense, quiescent clouds. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.