A hitherto unrecognized source of low-energy electrons in water
A hitherto unrecognized source of low-energy electrons in water
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DOI：
10.1038/nphys1500
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发表时间：
2010-02-01
期刊：
影响因子：
19.6
通讯作者：
Hergenhahn, Uwe
中科院分区：
文献类型：
--
作者：
Mucke, Melanie;Braune, Markus;Hergenhahn, Uwe
低能电子是凝聚态物质中电离辐射最丰富的产物。这些电子的起源通常被理解为通过入射辐射从核心或价态电离的二次电子，并通过多次非弹性散射事件减慢。在这里，我们研究了非晶态中等尺寸水簇中低能电子的产生，该水簇模拟了水环境中的水分子。我们发现了一种迄今为止未被认识的低能电子额外来源，该来源是由称为分子间库仑衰变（2）（ICD）的非局部自电离过程产生的。在用真空紫外光对内价态产生的低能电子和光电子进行符合测量时，观察到了这一过程的明确特征。由于 ICD 预计普遍发生在元素周期表中碳和氖之间含有轻原子的弱结合聚集体中 (2,3)，这些结果可能对我们理解活体组织中的电离损伤产生影响。
Low-energy electrons are the most abundant product of ionizing radiation in condensed matter. The origin of these electrons is most commonly understood to be secondary electrons' ionized from core or valence levels by incident radiation and slowed by multiple inelastic scattering events. Here, we investigate the production of low-energy electrons in amorphous medium-sized water clusters, which simulate water molecules in an aqueous environment. We identify a hitherto unrecognized extra source of low-energy electrons produced by a non-local autoionization process called intermolecular coulombic decay(2) (ICD). The unequivocal signature of this process is observed in coincidence measurements of low-energy electrons and photoelectrons generated from inner-valence states with vacuum-ultraviolet light. As ICD is expected to take place universally in weakly bound aggregates containing light atoms between carbon and neon in the periodic table(2,3), these results could have implications for our understanding of ionization damage in living tissues.