CO_(2)^(q+)(q≤4)在强激光场中的碎裂动力学研究  

Study of fragmentation dynamics for CO_(2)^(q+)(q≤4) in strong laser fields

作　　者：张帅 江文斌 王新成 江玉海 朱志远[1,2,4] ZHANG Shuai;JIANG Wenbin;WANG Xincheng;JIANG Yuhai;ZHU Zhiyuan(Shanghai Institute of Applied Physics,Chinese Academy of Sciences,Shanghai 201800,China;University of Chinese Academy of Sciences,Beijing 100049,China;Shanghai Advanced Institute,Chinese Academy of Sciences,Shanghai 201204,China;ShanghaiTech University,Shanghai 201210,China)

机构地区：[1]中国科学院上海应用物理研究所,上海201800 [2]中国科学院大学,北京100049 [3]中国科学院上海高等研究院,上海201204 [4]上海科技大学,上海201210

出　　处：《核技术》2022年第5期55-64,共10页Nuclear Techniques

基　　金：国家自然科学基金(No.11827806);上海市科技重大专项(No.2017SHZDZX02)资助。

摘　　要：分子碎裂动力学的研究在物理学、化学和生物学等研究领域受到广泛关注,在实验和理论研究方面已开展了大量的工作。利用强飞秒激光脉冲诱导CO_(2)分子的解离,通过冷靶反冲离子动量谱仪测量获取离子碎片的动量信息。进一步通过光离子-光离子符合(Photoion-Photoion Coincidence,PIPICO)技术和光离子-光离子-光离子符合(Photoion-Photoion-Photoion Coincidence,PIPIPICO)技术精确识别两体和三体解离通道,研究CO_(2)分子碎裂动力学机制。实验观测到了CO_(2)^(q+)(q=2~4)4个两体解离通道,揭示了动力学准直机理在所有两体碎裂通道中都占据主导作用。对于三体解离通道,通过氧离子碎片动量关联图、牛顿图和动能释放谱对CO_(2)^(q+)(q=3、4)的顺序和非顺序碎裂动力学过程的细致研究,结果显示在顺序碎裂过程中,作为中间体的CO^(2+)离子起着重要作用,表明CO^(2+)离子的旋转先于顺序碎裂过程的第二步碎裂发生。[Background]The research of molecular fragmentation dynamics has attracted extensive attention in the fields of physics,chemistry and biology.The major challenge in this field is to understand the selectivity of molecular bond breaking and to elucidate which parameters control bond fission.[Purpose]This study aims to reveal the mechanism of two and three-body fragmentation of CO_(2)in strong laser fields and to elucidate the dynamics information of the ion fragmentation in the Coulomb explosion.[Methods]The time-of-flight(TOF)and three dimensional momentum distributions of ion fragments were obtained using a cold-target recoil ion momentum spectroscopy(COLTRIMS).Precise identification of the two-body and three-body dissociation channels of CO_(2)was determined by the photoion-photoion coincidence(PIPICO)and the photoion-photoion-photoion coincidence(PIPIPICO)techniques.The occurrence of sequential and non-sequential fragmentation during three-body dissociation was revealed by the momentum correlation between two O ions.Finally,the dynamics of the three-body fragmentation process was visualized by the Newton diagram.[Results]Four two-body dissociation channels and three three-body dissociation channels for CO_(2)^(q+)(q≤4)are identified with the coincidence technique.The kinetic energy release(KER)distribution of these dissociation channels is obtained from the three-dimensional momentum.[Conclusions]The experiments reveal that the dynamic collimation mechanism plays a dominant role in the two body fragmentation channels,and the ion fragments of the four two-body fragmentation channels are mainly emitted along the laser polarization direction with the significant anisotropic distribution.Non-sequential and sequential fragmentation of CO_(2)is separated and identified in the momentum correlation and Newtonian diagrams.In the first step of the sequential fragmentation of CO_(2)^(4+),the O^(2+)and CO^(2)+ionic fragments are always produced.It is further shown that the vibration and rotation of the CO^(2)+ion are sh

关 键 词：强激光场 碎裂机制 库仑爆炸 反冲离子动量谱仪 

分 类 号：TL99[核科学技术—核技术及应用] O561.4[理学—原子与分子物理]