Yield enhancement of molecular ions with MeV ion-induced electronic excitation
Yield enhancement of molecular ions with MeV ion-induced electronic excitation
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DOI：
10.1016/j.apsusc.2008.05.108
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发表时间：
2008-12-15
影响因子：
6.7
通讯作者：
Matsuo, J.
中科院分区：
文献类型：
--
作者：
Nakata, Y.;Honda, Y.;Matsuo, J.
我们对入射能量在10 keV ~ 2 MeV范围内的精氨酸薄膜进行了二次离子质谱分析，其表面区域的电子能量损失随能量增加而增加，并且超过了核能损失。质子化精氨酸的产率随入射能量的增加而增加，在2 MeV时比在10 keV时大约大两个数量级，在10 keV时，核碰撞过程占主导地位。结果表明，近表面区域的电子激发增强了分子离子的脱附。此外，碎片离子对质子化精氨酸的产率随入射能量的增加而降低，表明核能沉积对分子碎片化有显著影响。这些结果证明了MeV离子诱导的电子激发对生物分子的软解吸和电离。(C) 2008 Elsevier b.v.版权所有
We performed secondary ion mass spectrometry for arginine thin films in the incident energy range from 10 keV to 2 MeV, in which electronic energy loss in the surface region increases with energy and exceeds the nuclear energy loss. The yield of protonated arginine increased with incident energy, and at 2 MeV it was approximately two orders of magnitude larger than at 10 keV, where the nuclear collision process is dominant. It was found that the molecular ion desorption is enhanced by the electronic excitation induced in the near-surface region. In addition, the yield ratios of the fragment ions to the protonated arginine decreased with incident energy, which indicates that the nuclear energy deposition significantly affects molecular fragmentation. These results demonstrate a soft desorption and ionization of biomolecules by the MeV ion-induced electronic excitation. (C) 2008 Elsevier B. V. All rights reserved.