The radiation chemistry of CO has been studied, using principally low-energy protons from a Van de Graaff accelerator, as a function of dose rate, temperature and small amounts of additives (CO2 and O2). At dose rates higher than those used in previous work a true dose-rate inhibition effect has been found which is interpreted on the basis of competition between second-order and first-order processes. The effect of CO2 on yields is negligible at concentrations up to 0.5% by volume but initial yields are extremely sensitive to traces of O2, particularly at low dose rates.
Increased temperature reduces yields of solid and increases yields of CO2, but this effect is controlled mainly by subsequent thermal decomposition of the solid. The empirical composition of the solid is unaffected by changes in dose rate, and varies from (C3O2)n at room temperature to essentially pure carbon at temperatures >450°C. Nucleation of the solid occurs predominantly in the gas phase. The relative importance of ionic and excitation processes is discussed.
使用范德格拉夫加速器产生的主要为低能质子的辐射,研究了剂量率、温度和小量添加剂(
CO2和O2)对CO的辐射
化学作用。在高于先前研究中所使用的剂量率下,发现了真正的剂量率抑制效应,该效应基于二阶和一阶过程之间的竞争来解释。在体积浓度高达0.5%时, 对产量的影响可以忽略不计,但初始产量对微量O2极其敏感,尤其是在低剂量率下。
温度升高会降低固体产量并增加 产量,但这种效应主要受固体随后热分解的控制。固体的经验组成不受剂量率变化的影响,且从室温下的(
C3O2)n变化到450°C以上温度时基本上为纯碳。固体的成核主要发生在气相中。讨论了离子过程和激发过程的相对重要性。