摘要
利用分子束飞行时间质谱和激光电离技术研究C4H2等离子体放电过程产生的中性碳氢团簇(CnHm)的质谱分布、稳定结构和形成机理.实验结果显示,碳氢团簇的质谱峰分布与其所含碳原子的个数有关,当碳原子的个数小于等于8时,偶数碳的碳氢团簇由于共轭效应的影响,其稳定性和质谱峰的强度均大于奇数碳的碳氢团簇;当碳原子的个数大于等于9时,出现偶数和奇数碳氢团簇的相间分布,奇数碳的碳氢团簇的质谱峰强度大于与其相邻的两个偶数碳的碳氢团簇的;当碳原子的个数为6、8、9～15、17时,CnH3出现较强的质谱峰,这与其具有较低电离能有关.随着碳原子个数的增加,碳氢团簇质谱峰的强度总体呈现减弱趋势,这说明碳氢团簇的形成机理可能以碳原子分步加成为主.
The mass spectrometric distribution,stable structure and the synthesis mechanism of neutral hydrocarbon clusters（C n H m） from C 4 H 2 plasma discharge are studied by molecular-beam timeof-flight mass spectrometry and laser ionization technology.The experimental results show that the distribution of mass spectrometric peaks is dependent on the number of carbon（n） of C n H m.When n ≤8,the peak signals strength and stability with the even-n groups are stronger than those of odd-n groups due to conjugative effect.The alternation of C n H m peak signals with even / odd n groups appears for n≥9with the odd-n groups having stronger signals.When n=6,8,9-15,17,stronger abundant clusters are C n H 3 due to their low ionization potentials.The C n H m mass spectrometric signals generally become weak with increasing n,which indicates the synthesis mechanism is mainly based on a step-addition approach.
出处
《大连理工大学学报》
EI
CAS
CSCD
北大核心
2012年第6期799-802,共4页
Journal of Dalian University of Technology
关键词
C4H2
等离子体放电
碳氢团簇
激光电离
分子束飞行时间质谱
C4H2
plasma discharge
hydrocarbon clusters
laser ionization
molecular-beam time-offlight mass spectrometry
