低能离子碰撞多原子分子碎裂过程的完全关联动力学研究

Study of the fragmentation of molecule induced by highly charged ions is of great interest not only because of its fundamental nature to understand the physical mechanisms but also because of its various applications in many fields, such as astrophysical plasma and radiation damage of biological tissues. The reaction microscope enables one to measure the momentum vectors of all fragments with high resolution and unprecedented efficiency. In this project, we plan to study the fragmentation of symmetric polyatomic molecule following electron capture or transfer ionization process induced by low-energy highly-charged ions using the reaction microscopes. The three-dimensional momentum vectors of all the fragments are measured in coincidence with the scattered projectile. The fragmentation dynamics and the role played by the emitted electron and the outgoing projectile will be investigated in detail. Special emphasis will be devoted to explore which of several symmetric bonds will break. This project will be very helpful to understand the complete correlation dynamics of the coupled motions of electrons, recoil ions and scattered projectile during the fragmentation process of molecules beyond the Born-Oppenheimer approximation.

研究分子的解离碎裂过程不仅有助于人们理解物理机制等基本问题，同时还在天体等离子体物理、生物组织辐射损伤等其它学科中有着广泛的应用。反应显微成像谱仪技术的发展使得对原子分子碰撞末态反应产物的运动学完全测量成为可能。本申请拟利用反应显微成像谱仪开展低能高电荷态离子俘获或转移电离导致的多原子分子解离实验，对末态所有产物进行多重符合的运动学完全测量，突破目前玻恩-奥本海默近似研究范畴，通过考察对称多原子分子电离解离时对称共价键的选择性断裂等现象，详细研究分子电离解离过程中低能出射电子和散射炮弹离子对分子离子解离过程的影响，在此基础上理解超越玻恩-奥本海默近似的分子电离解离过程中剩余靶离子、出射电子和散射炮弹离子间运动耦合的完全关联动力学。

研究分子的解离碎裂过程不仅有助于人们理解物理机制等基本问题，同时还在天体等离子体物理、生物组织辐射损伤等其它学科中有着广泛的应用。我们利用反应显微成像谱仪，通过升级改造实验装置，实现了对多原子分子反应碎片动量的多重符合测量，在此基础上，开展了低能高电荷态离子俘获或转移电离引起的多原子分子乙炔和甲烷的解离碎裂动力学研究，通过考察不同碰撞电离机制下反应碎片离子的空间角分布和动能释放，研究了分子电离解离过程的完全关联动力学，发现对称分子碎裂的取向效应和炮弹离子在分子电离过程中的速度及电荷效应，显示出低能高电荷态离子或电子与分子碎片离子在解离碎裂过程中的关联性。此外，进一步开展了不同能量高电荷态离子引起的环丙烷和丙烯、丙炔和丙二烯等多原子分子的解离碎裂动力学以及离子碰撞原子的俘获过程机制研究，揭示了分子多体碎裂动力学机制，发现炮弹速度效应对分子碎裂模式的影响，观察到了显著的同分异构体效应，此外还研究了单电子俘获基本过程态选择俘获机制以及双电子俘获过程中双激发态形成机制。