Formation of H₂CO and C0₂ on an icy grain analogue using fast H-atoms

Formadehyde (H₂CO) and carbon dioxide (CO₂) are produced in collisions of a superthermal, 3 eV beam of H(²S) atoms with CO molecules adsorbed on a gold surface at 4.8K. The reaction-generated products are detected and anayzed using the techniques of temperature programmed desorpton (TPD), quadrupole mass spectrometry (QMS), and a novel application of the Metropolis random-walk procedure to identify the unique fractionaton patterns of H₂CO and CO₂ from the patterns of other species such as N₂, CO, and H₂0 embedded in the CO blanket and devolved in the TPD/MS process. Reaction sequences will be given to account for the formaton of H₂CO and C0₂.