Relation between biomolecular dissociation and energy of secondary electrons generated in liquid water by fast heavy ions
Relation between biomolecular dissociation and energy of secondary electrons generated in liquid water by fast heavy ions
复制标题
液态水中快重离子产生的二次电子与生物分子解离和能量的关系
DOI：
10.1140/epjd/e2020-10172-x
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Saito Manabu
中科院分区：
文献类型：
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作者：
Tsuchida Hidetsugu;Kai Takeshi;Kitajima Kensei;Matsuya Yusuke;Majima Takuya;Saito Manabu
摘要本工作中，我们测量并模拟了在快重离子辐照下，水分子发射的二次电子引起的液态水中生物分子的解离。我们计算了液态水中碳离子沿沿着径迹产生的二次电子在布喇格峰区的能谱。计算采用碳径迹结构模式下的粒子和重离子输运程序系统（PHITS）。这种模式使非弹性碰撞的模拟沿着碳离子轨道的基础上考虑在蒙特卡罗代码KURBUC的横截面。为了了解我们以前的MeV-SIMS实验中的生物分子解离过程与甘氨酸溶液的微滴目标，我们计算了二次电子的碰撞光谱附近的液体表面使用PHITS。此外，我们研究了二次电子能量和形成的积极和消极的甘氨酸片段之间的关系。结果表明，亚甲基胺阳离子的形成是由能量为13-100 eV的二次电子引起的。甘氨酸相关的负离子，如氰化物阴离子，甲酸根阴离子，和去质子化甘氨酸的形成被发现是由低能量（小于13 eV）的二次电子。这些离子是已知的解离电子附着的产物。
AbstractIn this work, we measured and simulated the dissociation of biomolecules in liquid water induced by secondary electrons ejected from water molecules during fast heavy-ion irradiation. We calculated the energy spectra of secondary electrons generated along carbon ion tracks in liquid water in the Bragg peak region. The calculation was done using the Particle and Heavy Ion Transport code System (PHITS) in carbon track structure mode. This mode enables simulation of inelastic collisions along a carbon ion track based on the cross sections considered in the Monte Carlo code KURBUC. To understand the biomolecular dissociation processes in our previous MeV-SIMS experiments with microdroplet targets of glycine solution, we calculated the collision spectra of secondary electrons produced near liquid surfaces using PHITS. Furthermore, we examined the relationship between the secondary electron energy and formation of positive and negative glycine fragments. The results showed that the formation of methylene amine cations is caused by secondary electrons with energies of 13–100 eV. The formation of glycine-related negative ions such as cyanide anion, formate anion, and deprotonated glycine was found to be caused by low-energy (less than 13 eV) secondary electrons. These ions are known products of dissociative electron attachment.Graphical abstract