Cross sections for positron and electron collisions with an analog of the purine nucleobases: Indole
Cross sections for positron and electron collisions with an analog of the purine nucleobases: Indole
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DOI：
10.1103/physreva.91.012711
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发表时间：
2015-01-26
影响因子：
2.9
通讯作者：
Brunger, M. J.
中科院分区：
文献类型：
--
作者：
Chiari, Luca;Zecca, Antonio;Brunger, M. J.
在带电粒子径迹模拟中需要关于正电子和电子与核碱基碰撞的定量信息，以准确地模拟和评估生物系统中亚细胞水平的任何辐射损伤。然而，散射实验到目前为止仅限于嘧啶核碱基。在本文中，我们报告的总截面测量的正电子碰撞吲哚，嘌呤核碱基的母体分子，在1和25 eV之间的冲击能量。我们还提出了弹性和总散射，电子偶素形成，电子激发，和1和500 eV之间的直接电离的理论截面，计算与屏蔽校正的加性规则的独立原子模型。另外，在相同的能量范围内的玻恩框架内计算旋转激发截面。一个显着的差异被发现之间的测量和计算的总截面，这不能完全占在实验中缺乏前向角散射歧视。目前的结果也比较可用的嘌呤核碱基的理论截面。此外，我们的理论形式主义内计算的电子吲哚碰撞的总截面。
Quantitative information about positron and electron collisions with nucleobases is required in charged-particle track simulations to accurately model and assess any radiation damage at the subcellular level in biological systems. However, scattering experiments have so far been restricted to the pyrimidine nucleobases. In this paper we report on total-cross-section measurements for positron impact on indole, a parent molecule of the purine nucleobases, at impact energies between 1 and 25 eV. We also present theoretical cross sections for elastic and total scattering, positronium formation, electronic excitations, and direct ionization between 1 and 500 eV, as calculated with the independent-atom model with the screening-corrected additivity rule. Rotational excitation cross sections are additionally calculated within a Born framework over that same energy range. A significant discrepancy is found between the measured and computed total cross sections, which cannot be entirely accounted for by the lack of forward-angle-scattering discrimination in the experiment. The present results are also compared to the available theoretical cross sections for the purine nucleobases. In addition, total cross sections for electron-indole collisions computed within our theoretical formalism are provided.