Momentum imaging spectroscopy of fragment ions produced in highly charged ion - molecule collisions controlled by the heat of formation

本研究最重要的目的是发展一种实验技术，以确定高电荷离子与分子碰撞中中间态与后续破碎过程之间的关系。为了研究离子与分子之间电子转移引起的碎片化过程，有必要确定碰撞后分子产生的中间态。然而，由于目前只选择了入射离子的电荷态变化，因此没有获得关于中间态的信息。在这项研究中，我们开发了一种新的光谱装置，它不仅可以测量电荷状态的变化，还可以根据碎片离子的三维动量图像测量动能的变化。这项研究还包括开发一种紧凑型离子源，在没有任何冷却系统的情况下产生高电荷离子。本项目第一期（2000年）研制了一种紧凑的多电荷离子源，并发表了相关论文。离子源的尺寸非常小（长40厘米，直径20厘米），功耗非常低（4 W）。利用一对钕铁硼永磁体和特殊形状的磁轭，成功地从离子源中萃取出Ne^<10+>、Ar^<18+>和Kr^<29+>。在项目的最后一个学期（2001年），开发了sd动量成像分析仪。我们参加了一些会议并出版了会议记录。利用该分析仪不仅可以测量电荷态的变化，还可以根据碎片离子的sd动量图像测量动能的变化。该装置可以在电子转移碰撞后立即确定入射离子和靶分子的电子态。首次有可能确定Ar^<q+> （q=3、8、9、11和12）与N_2、CH_4和CF_4分子碰撞时分子的电子态。此外，还得到了分子取向和断裂不对称性的一些信息。少

The most important purpose of this research is developing of an experimental technique to identify the correlation between an intermediate state and following fragmentation processes in collisions between highly charged ion and molecule. In order to investigate fragmentation processes induced by electron transfer between ion and molecule, it is necessary to specify an intermediate state of molecule produced just after the collision. No information about the intermediate state, however, had been obtained because only charge-state change of incident ion had been selected until now. In this research, we developed a hew spectroscopic device which is able to measure not only charge-state change but also kinetic energy change in coincidence with 3D-momentum image of fragment ions. This research also includes development of a compact ion source producing highly charged ions without any cooling system.In the first term of this project (2000), a compact multiply-charged ion source was developed … More , and a related paper was published. The size of the ion source is very small (40 cm long and 20 cm diameter) and the power consumption is very low (4 W). Extraction of Ne^<10+>, Ar^<18+>, and Kr^<29+> was succeeded from the ion source by using a pair of NdFeB permanent magnets and special shaped yokes.In the last term of this project (2001), the SD-momentum imaging analyzer was developed. We participated in some conferences and published the proceedings. It is possible to measure not only charge-state change but also kinetic energy change in coincidence with SD-momentum image of fragment ions by using this analyzer. This device makes it possible to assign both electronic states of incident ion and target molecule just after the electron transfer collision. It was possible to specify the electronic states of molecules in collisions between Ar^<q+> (q=3, 8, 9, 11, and 12) and N_2, CH_4, and CF_4 molecules for the first time. In addition, some information on molecular orientation and asymmetry of fragmentation were obtained from the results. Less