Ions in carbon dioxide at an atmospheric pressure

The formation and decay of cluster ions, (CO2)+sub(n), (CO(CO2)sub(n))+, ((CO)2(CO2)sub(n))+, H2O(CO2)sub(n))+, (H(H2O)(CO2)sub(n))+, and (H(H2O)2(CO2)sub(n))+ in atmospheric pressure carbon dioxide are observed with a time-resolved atmospheric pressure ionization mass spectrometer. It was found that the reaction of the cluster ions is not always analogous to that of the corresponding bare ions, and that a trace amount of impurities, i.e. H2O and CO, causes a decisive effect on the reaction course of cluster ions. Relevance of these observations is discussed to the radiolysis of carbon dioxide. (author)