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

Abstract

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.