重离子诱导的水分子与氙原子之间能量传递过程的实验研究

项目名称： 重离子诱导的水分子与氙原子之间能量传递过程的实验研究

项目编号： No.U1532129

项目类型： 联合基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 闫顺成

作者单位： 中国科学院近代物理研究所

项目金额： 62万元

中文摘要： 与传统放疗技术相比，重离子治癌技术优势明显。但是由于生物分子普遍存在于由水团簇构成的环境中，当发生重离子电离辐射时，该环境会与其中的分子发生能量传递，并引起复杂的物理现象。这就导致生物组织的电离解离机理至今尚不清楚。本申请拟利用反应显微成像谱仪开展重离子诱导的水氙混合团簇(H2O)Xe的解离实验，确定水分子是否可以通过原子间库仑退激（Interatomic Coulombic Decay）向Xe原子传递能量，使其发射低能电子，用以模拟水环境与生物分子之间的能量传递过程。该过程可以使生物分子自身发射低能电子，导致自身DNA链的断裂。同时，我们拟开展高电荷态离子与水氙混合团簇的碰撞实验，通过双点双电离（Two-Site Double Ionization）得到水分子和Xe原子对应的碰撞参数分布；同时确定H2O分子的空间取向，研究H2O分子的空间取向与单电离反应动力学的依赖关系。

中文关键词： 重离子；动力学；电离解离；分子取向；库仑爆炸

英文摘要： Although heavy ion radiotherapy has obvious advantages compared with conventional radiotherapy, the heavy ion induced fragmentation mechanisms of biological molecules are still unclear. The reason is that, the biological molecules are embedded in the environment constituted by water clusters, the environment will transfer energy to the biological molecules during heavy ion ionizing radiation. This application is intended to carry out the fragmentation experiment of (H2O)Xe induced by heavy ion impact. This experiment can simulate the energy transfer process between Xe atoms and water environment, and identify the whether the water environment can transfer virtual photon to the Xe atom by Interatomic Coulombic Decay. In the view of radiation damage, this process can lead to emission of low-energy electrons from biological molecules, and resulting in the break of their own DNA strand. Our study can effectively promote the understanding of the radiation damage process. At the same time, we intend to carry out the (H2O)Xe fragmentation experiment induced by highly charged ion impact. Through Two-Site Double Ionization, the collision parameter and orientation of H2O+ ions can be determined, and the correspondence between the H2O molecular orientation and single ionization dynamics can be obtained.

英文关键词： Heavy Ion;Dynamics;Dissociative Ionization;Molecule Orientation;Coulombic Explosion