碳簇分子和离子的合成及质谱研究

Mass Spectrometer Study of Carbon Clusters and Their Ions

利用脉冲等离子体反应器 ,采用 C2 H2 /Ar,CH4 /Ar,C6H6/Ar放电合成碳簇分子和离子 .采用 TOF-飞行时间质谱和激光电离技术来研究和分析产物分布 .讨论了在不同实验条件下 ,中性碳簇分子和离子的分布情况 ,并对反应过程和机理进行了讨论 .从反应机理来看 ,在相似的等离子条件下 ,采用不同的气体 ,如 C2 H2 /Ar,CH4 /Ar,C6H6/Ar等所得到碳簇分布非常相似 .另外 ,当增加等离子体反应器通道长度 (增大反应时间 ) ,碳簇的尺寸也有增加的趋势 .即较大的碳簇需要较多的反应步骤和较长的反应时间 .这表明 。

The carbon clusters and their ions in m ed ium size (n=2～30) was generated by discharging CH 4/Ar,C 2H 2/Ar or C 6H 6/Ar mixtures in pulse plasma micro-reactor.The time-of-flight(TOF) mass spectrometer and laser ionization technique were used to analysis and study the distribution of the species generated.Through their distributions,the react ion mechanism of carbon clusters and their ions was proposed.As with CH 4/Ar, C 2H 2/Ar or C 6H 6/Ar,the very similar distributions were shown,whi ch indicates the synthesis mechanism is a step addition(C n+C→C n+1 ).Another strong evidence to support this mechanism is that the reactor with a longer channel always produces the clusters of bigger size,because the synthes is of the clusters of big size generally take much more steps and longer period of reacting time.