Absolute partial and total cross‐section functions for the electron impact ionization of C60 and C70
Absolute partial and total cross‐section functions for the electron impact ionization of C60 and C70
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C60 和 C70 电子碰撞电离的绝对部分和总截面函数
DOI：
10.1063/1.472059
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发表时间：
1996
影响因子：
4.4
通讯作者：
T. Märk
中科院分区：
文献类型：
--
作者：
S. Matt;B. Dünser;M. Lezius;H. Deutsch;K. Becker;A. Stamatović;P. Scheier;T. Märk
采用分子/电子束离子源，结合离子束偏转模式的双扇形场质谱仪，研究了C60和C70的电子冲击电离。从阈值到1000 eV的电子能量范围内，确定了产生单电荷和多电荷母离子（直到电荷态z=4）和碎片离子（在C60的情况下低至C+44，在C70的情况下低至C2+50）的相对部分电离截面。绝对部分电离截面和总电离截面是用一种新的方法获得的，用于绝对校准，涉及阳离子和阴离子产率的相互比较。结果表明，与其他电离通道相比，该通道不仅具有异常大的母离子横截面[例如，σ(C+60/C60)比σ(C+58/C60)大30倍以上]，而且产生多电荷母离子和碎片离子也存在异常。例如，形成C2+60的最大横截面为30%…
Electron impact ionization of C60 and C70 was studied using a molecular/electron beam ion source in combination with a two sector field mass spectrometer operated in the ion beam deflection mode. Relative partial ionization cross sections for the production of singly and multiply charged parent ions (up to charge state z=4) and fragment ions (down to C+44 in the case of C60 and down to C2+50 in the case of C70) were determined from threshold up to 1000 eV electron energy. Absolute partial and total ionization cross sections are obtained using a novel approach for the absolute calibration involving an intercomparison of the cation with the anion yield. The results obtained reveal not only an anomalous large parent ion cross section as compared to other ionization channels [e.g., σ(C+60/C60) is more than a factor of 30 larger than σ(C+58/C60)] but also anomalies for the production of multiply charged parent and fragment ions. For instance, the maximum cross section for the formation of C2+60 amounts to 30% ...