一套用于研究原子团簇热力学的离子速度成像谱仪

发布时间：2018-04-21 04:30

本文选题：原子团簇 + 激发温度　；参考：《原子核物理评论》2016年04期

【摘要】：原子团簇的激发温度可由反应产物(出射电子或碎片)的初始平动能这一可观测量间接获得,为了提高原子团簇激发温度的测量精度,设计并搭建了一套具有高动能分辨的离子速度成像谱仪。本谱仪的高动能分辨性能首先借助Simion8.0软件优化静电透镜和分子束限束装置的几何结构来实现,然后通过理论模拟证明本套谱仪具有预期好的动能分辨能力。设备搭建完成后,研究了C60分子束在纳秒激光场中发生的延迟电离过程,获得了C_(60)~+离子随延迟时间增加而逐渐变窄的二维时间切片图像。分析表明,激光脉冲产生的多个C_(60)~+离子间的库仑耦合作用将会扩展二维切片图像的横向分布,提取库仑耦合作用对C_(60)~+离子初始平动能的影响,并通过分析C_(60)~+离子间的库仑耦合随延迟时间增加而逐渐变弱的定量依赖关系,证实了本套谱仪具有了设计预期的高动能分辨能力。这一工作为下一步基于离子速度成像技术细致研究分子热力学的相关课题提供技术参考。
[Abstract]:The excitation temperature of the cluster can be obtained indirectly by the observable measurement of the initial flat kinetic energy of the reaction product (emitting electron or fragment). In order to improve the accuracy of the measurement of the excitation temperature of the cluster, A set of ion velocity imaging spectrometer with high kinetic energy resolution is designed and built. The high kinetic energy resolution of this spectrometer is realized by optimizing the geometry structure of electrostatic lens and molecular beam limiting device by Simion8.0 software, and then the theoretical simulation proves that this spectrometer has the desired kinetic energy resolution ability. The delayed ionization process of C60 molecular beam in nanosecond laser field was studied after the equipment was completed, and a two-dimensional slice image of C60 ~ + gradually narrowed with the increase of delay time was obtained. The analysis shows that the Coulomb coupling between several CID ions generated by laser pulses will expand the transverse distribution of two-dimensional slice images, and extract the effect of Coulomb coupling on the initial flat kinetic energy of Che 60 ~ + ions. By analyzing the quantitative dependence that the Coulomb coupling between Che ~ + ions weakens gradually with the increase of delay time, it is proved that this spectrometer has the expected high kinetic energy resolution ability. This work provides a technical reference for the further detailed study of molecular thermodynamics based on ion velocity imaging technology.
【作者单位】：河南科技大学物理工程学院;中国科学院近代物理研究所;西北师范大学物理与电子工程学院;
【基金】：国家自然科学基金资助项目(U1232122,10904152)~~
【分类号】：TH70

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