Mechanism of hydrocarbon formation upon interaction of energetic hydrogen ions with graphite
Mechanism of hydrocarbon formation upon interaction of energetic hydrogen ions with graphite
复制标题
高能氢离子与石墨相互作用形成碳氢化合物的机制
DOI：
10.1063/1.98777
复制
发表时间：
1987
影响因子：
4
通讯作者：
J. Bohdansky
中科院分区：
文献类型：
--
作者：
J. Roth;J. Bohdansky
目前的模型为碳氢化合物的形成后，高能氢离子与石墨的相互作用，假设吸附的氢与碳表面原子的反应，需要800-900 K的温度。该模型受到分层13 C/12 C样品碳氢化合物形成结果和室温注入后解吸测量结果的强烈质疑。在用200 A的13 C层覆盖的热解石墨样品的氘轰击期间监测13 CD 4和12 CD 4的形成。只有当离子能量小于200 A时，13 CD 4才占主导地位，而在更高的能量下，只有12 CD 4存在。因此，甲烷是在离子范围的末端形成的，而不是在反向扩散离子的表面反应中形成的。在室温植入后使用缓慢温度范围的解吸实验显示在D2之前释放CD 4，因此表明在植入期间已经形成的CD 4的扩散限制释放。
The current model for hydrocarbon formation upon the interaction of energetic hydrogen ions with graphite assumes a reaction of adsorbed hydrogen with carbon surface atoms requiring a temperature of 800–900 K. This model is strongly questioned by results of hydrocarbon formation from a layered 13C/12C sample and by desorption measurements after room‐temperature implantation. The formation of 13CD4 and 12CD4 is monitored during deuterium bombardment of a pyrolytic graphite sample covered with a layer of 200 A of 13C. Only for ion energies corresponding to ranges smaller than 200 A 13CD4 dominates, while at higher energies only 12CD4 is found. The methane is thus formed at the end of ion range rather than in a surface reaction of back‐diffusing ions. Desorption experiments using a slow temperature range after room‐temperature implantation show the release of CD4 prior to D2, thus indicating a diffusion‐limited release of CD4 already formed during the implantation.