Atoms adsorbed on cold surfaces react with energetic impinging atoms.

A method of making more-complex molecules from simpler ones has emerged as a by-product of an experimental study in outer-space atom/ surface collision physics. The subject of the study was the formation of CO₂ molecules as a result of impingement of O atoms at controlled kinetic energies upon cold surfaces onto which CO molecules had been adsorbed. In this study, the O/CO system served as a laboratory model, not only for the formation of CO₂ but also for the formation of other compounds through impingement of rapidly moving atoms upon molecules adsorbed on such cold interstellar surfaces as those of dust grains or comets. By contributing to the formation of increasingly complex molecules, including organic ones, this study and related other studies may eventually contribute to understanding of the origins of life.