AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuA

Paper SS1-TuA4
Surface Science - A New Tool for Laboratory Astrophysics

Tuesday, November 4, 2003, 3:00 pm, Room 326

Session: Water at Interfaces II: Adsorbed Layers
Presenter: M.R.S. McCoustra, University of Nottingham, UK
Authors: M.P. Collings, University of Nottingham, UK
J.W. Dever, University of Nottingham, UK
H.J. Fraser, University of Leiden, The Netherlands
M.R.S. McCoustra, University of Nottingham, UK
Correspondent: Click to Email
The evolution of our galaxy, and that of others in the Universe, is subtley controlled by a combination of physics and chemistry. Molecules prevade the galaxy and are found to play a key role in controlling the very processes that give birth to new stars, their planetary systems, and potentially the precursors of life itself. Astronomical observations can give us much detail as to the nature of these molecules but laboratory measurements are necessary to understand the physics and chemistry that lead to their formation. Gas phase chemistry is important in this respect, but in recent years the molecular astrophysics community has come to realise that the interaction of the interstellar gas with solid grains plays a crucial role. Our laboratory effort has sought to apply surface science techniques and methodologies to understanding aspects of the gas-grain interaction. In particular, we will report on combined temperature-programmed desorption (TPD) and reflection-absorption infrared spectroscopy (RAIRS) measurements of the interaction of carbon monoxide (CO), carbon dioxide (CO@sub 2@) and molecular hydrogen (H@sub 2@) with vapour deposited ultrathin films of water (H@sub 2@O) ice under conditions that a closely mimic those in the denser regions of the interstellar medium where stars are known to form. Results will be presented that demonstrate a complex interplay of surface diffusion, substrate morphological change, pore trapping of gases and desorption that modifies the simple model of the behaviour of these systems currently utilised by the molecular astrophysics community.