2009ApJ...697..801M

Formaldehyde (H₂CO) and carbon dioxide (CO₂) were produced in collisions of a superthermal, 3 eV beam of H(²S) atoms with CO molecules adsorbed on a gold surface at 4.8 K. The reaction-generated products were detected and analyzed using the techniques of temperature programmed desorption (TPD), quadrupole mass spectrometry, and a novel application of the Metropolis algorithm, random-walk procedure to identify the unique fractionation patterns of H₂CO and CO₂ from the patterns of other species such as N₂, CO, and H₂O embedded in the CO blanket and devolved in the TPD/mass spectrometry process. Reaction sequences are given to account for the formation of H₂ CO and CO₂.