γ Radiolysis of Gaseous Carbon Dioxide at High Densities

Abstract

The γ radiolysis of gaseous carbon dioxide has been investigated at 50 ± 1°C over the density range of 0.2 to 0.6 g/ml. At density of around 0.5 g/ml, G(CO) from pure carbon dioxide showed a very marked increase. Addition of SF6 at these densities efficiently reduced G(CO). From this it appears that formation of carbon monoxide results mostly from charge neutralization. Examination of the mechanisms in the radiolysis of carbon dioxide in gas and liquid phase, and a calculation on a simple model indicate that this neutralization is of geminate character. Upon addition of hydrocarbons which react with oxygen atoms as well as the addition of both hydrocarbons and SF6, G(CO) passed through a maximum and reached the value of 2.2 at higher concentrations of hydrocarbons, independent of density. It was interpreted that (1) the positive ions involved in neutralization are probably clustered CO2 + in agreement with the above inference, and that (2) there are at least two species responsible for the rapid re-oxidation of CO.