Instituto de Física Fundamental, Consejo Superior de Investigaciones Científicas-CSIC, Serrano 113-bis, 28006 Madrid, Spain.
Laboratório de Colisões Atómicas e Moleculares, CEFITEC, Departamento de Física, Universidade NOVA de Lisboa, 2829-516 Caparica, Portugal.
Int J Mol Sci. 2023 Jul 29;24(15):12182. doi: 10.3390/ijms241512182.
In this study, we present a complete set of electron scattering cross-sections from 1-Methyl-5-Nitroimidazole (1M5NI) molecules for impact energies ranging from 0.1 to 1000 eV. This information is relevant to evaluate the potential role of 1M5NI as a molecular radiosensitizers. The total electron scattering cross-sections (TCS) that we previously measured with a magnetically confined electron transmission apparatus were considered as the reference values for the present analysis. Elastic scattering cross-sections were calculated by means of two different schemes: The Schwinger multichannel (SMC) method for the lower energies (below 15 eV) and the independent atom model-based screening-corrected additivity rule with interferences (IAM-SCARI) for higher energies (above 15 eV). The latter was also applied to calculate the total ionization cross-sections, which were complemented with experimental values of the induced cationic fragmentation by electron impact. Double differential ionization cross-sections were measured with a reaction microscope multi-particle coincidence spectrometer. Using a momentum imaging spectrometer, direct measurements of the anion fragment yields and kinetic energies by the dissociative electron attachment are also presented. Cross-sections for the other inelastic channels were derived with a self-consistent procedure by sampling their values at a given energy to ensure that the sum of the cross-sections of all the scattering processes available at that energy coincides with the corresponding TCS. This cross-section data set is ready to be used for modelling electron-induced radiation damage at the molecular level to biologically relevant media containing 1M5NI as a potential radiosensitizer. Nonetheless, a proper evaluation of its radiosensitizing effects would require further radiobiological experiments.
在这项研究中，我们给出了 1-甲基-5-硝基咪唑（1M5NI）分子在 0.1 到 1000 eV 能量范围内的一套完整的电子散射截面数据。这些信息对于评估 1M5NI 作为一种潜在的分子增敏剂的作用具有重要意义。我们之前使用磁约束电子传输装置测量的总电子散射截面（TCS）被视为本次分析的参考值。弹性散射截面是通过两种不同的方案计算的：对于较低能量（低于 15 eV），使用 Schwinger 多通道（SMC）方法；对于较高能量（高于 15 eV），使用基于独立原子模型的屏蔽修正加和规则与干涉（IAM-SCARI）。后者也被用于计算总离化截面，这些截面与电子碰撞诱导阳离子碎片的实验值相补充。双微分离化截面是使用反应显微镜多粒子符合谱仪测量的。使用动量成像谱仪，还展示了通过电子碰撞的离解电子俘获直接测量阴离子碎片产率和动能的结果。其他非弹性通道的截面是通过在给定能量处抽样其值来用自洽程序推导的，以确保在该能量下所有散射过程的截面之和与相应的 TCS 相符。这个截面数据集已经准备好用于模拟含有 1M5NI 作为潜在增敏剂的生物相关介质中的分子水平上的电子诱导辐射损伤。然而，要对其增敏效果进行适当的评估，还需要进一步的放射生物学实验。
