物理化学学报 >> 2011, Vol. 27 >> Issue (08): 1797-1802.doi: 10.3866/PKU.WHXB20110717

热力学，动力学和结构化学 上一篇    下一篇

振动态选择的NO2+离子e3B2态解离生成氧离子通道的动力学

牛铭理1, 宋磊1, 唐小锋1, 周晓国1, 刘世林1, 刘付轶2, 单晓斌2, 盛六四2   

  1. 1. 中国科学技术大学化学物理系, 合肥微尺度物质科学国家实验室(筹), 合肥 230026;
    2. 中国科学技术大学, 合肥同步辐射国家实验室, 合肥 230029
  • 收稿日期:2011-02-28 修回日期:2010-04-06 发布日期:2011-07-19
  • 通讯作者: 周晓国 E-mail:xzhou@ustc.edu.cn
  • 基金资助:

    国家自然科学基金(10979042, 21073173)和国家重点基础研究发展规划项目(973) (2007CB815204)资助

Dissociation Dynamics of O+ Formation Channels from Vibrational State-Selected NO2+ at e3B2 State

NIU Ming-Li1, SONG Lei1, TANG Xiao-Feng1, ZHOU Xiao-Guo1, LIU Shi-Lin1, LIU Fu-Yi2, SHAN Xiao-Bin2, SHENG Liu-Si2   

  1. 1. Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China;
    2. National Synchrotron Radiation Laboratory and School of Nuclear Science and Technology, University of Science and Technology of China, Hefei 230029, P. R. China
  • Received:2011-02-28 Revised:2010-04-06 Published:2011-07-19
  • Contact: ZHOU Xiao-Guo E-mail:xzhou@ustc.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (10979042, 21073173) and National Key Basic Research Program of China (973) (2007CB815204).

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摘要：

结合最新的阈值光电子-光离子符合速度成像技术和同步辐射光电离, 开展了振动态选择的NO2+离子e3B2态解离动力学研究. 在18.8-19.2 eV范围内获得的NO2+离子e3B2态的振动分辨阈值光电子谱与前人结果基本符合, 而由e3B2态(0,0,0)和(1,0,0)振动能级解离生成的O+碎片离子的符合速度成像清楚地显示出多个圆环结构, 表明解离过程中生成了多种具有不同速度的O+离子, 对应中性解离碎片NO分子处于不同的内态. 通过速度和角度积分, 我们分别获得了解离过程中释放的总平动能分布和O+离子的角度分布, 其中两振动态选择的NO2+离子解离生成的NO分子X2Π态振动分布十分相似, 主要布居的振动量子数为3-5. 解离释放的可资用能近似平均分配到碎片的平动能和内能, 其中碎片总平动能约占52%, 内能约占48%. 此外, O+离子的各向异性参数β约为0.3, 且不随NO(X2Π)振动量子数而剧烈变化.

关键词: 解离动力学, 光电离, 阈值光电子谱, 光电子-光离子符合, 速度成像

Abstract:

The dissociation dynamics of vibrational state-selected NO2+(e3B2) was investigated using threshold photoelectron-photoion coincidence velocity imaging and photoionization by synchrotron radiation. The vibrational resolution threshold photoelectron spectrum of NO2+ (e3B2) was recorded in the energy range of 18.8-19.2 eV and was consistent with previous measurements. Furthermore, the coincident velocity images of the O+ fragments that dissociated from the (0,0,0) and (1,0,0) vibronic levels of NO2+ (e3B2) showed a multi-ring structure, indicating that O+ fragments with different speeds were produced during dissociation as well as corresponding NO molecules with different internal energy distributions. The total kinetic energy released distributions and the angular distributions of O+ during dissociation were obtained subsequently from the images. The internal energy distributions of the NO (X2Π) fragments that dissociated from the two vibrational states of NO2+(e3B2) were very similar and consisted of 3-5 dominant populated vibronic levels. The available energy released from dissociation was found to be almost evenly distributed between the kinetic and internal energies of the fragments and, specifically, a total kinetic energy of 52% and an internal energy of 48% were obtained. In addition, the anisotropy parameter, β, of the O+ fragments was about 0.3 and was hardly dependent on the vibrational quantum number of the NO(X2Π) fragment.

Key words: Dissociation dynamics, Photoionization, Threshold photoelectron spectrum, Photoelectron-photoion coincidence, Velocity map imaging