A STUDY OF DESTRUCTION OF HIGHLY EXCITED MOLECULAR IONS PRODUCED IN THE EXTREME-ULTRAVIOLET REGION

从伴随电子相关效应的高激发态分子化学的角度来看，与多激发态即光电离卫星的研究一样，由25 eV以上能量的光吸收激发的分子高激发态的研究也是非常重要的。本研究的目的是通过对电子激发的中性碎片的荧光进行同步测量，发展光谱方法来识别和观察这种分子高激发态的产生和衰变过程。如下图所示，本研究的目的已圆满完成。本研究是通过上述实验装置——重合光谱仪进行的，重合光谱仪由脉冲电磁气体喷嘴、荧光探测器和飞行时间质量分析仪组成，安装在目前可用的用于气相分子与极紫外光子束碰撞的高真空室中。通过对该装置的研制、调试和使用，在日本筑波高能物理国家实验室光子工厂利用单色同步辐射对氢、氮等典型双原子分子进行了研究。对于氮的结果，高激发离子解离成碎片离子（N^+）和电子激发的中性碎片离子（N^<**>）已被证明与从内价轨道发射电子产生的离子相对应，这在以前几乎没有得到任何信息。对片段离子与荧光光子的同步激发函数随激发光子能量的变化进行了详细测量。此外，还成功地利用同步辐射偏振轴的角相关重合光谱揭示了各种对称离子态的产生。这是证明单电子离子态与多重激发中性分子之间有很强的相关性的明确证据。在此基础上，进行了分散荧光的测量。研究表明，离子片段的荧光有重要贡献，并且某一分子离子态与某一片段对有关。对于氢的结果，符合谱表明，具有另一个单电子激发的单电子离子态解离成H^+和H^<**>，并通过测量二维符合谱对其进行了详细的研究。利用静电分析仪对碎片离子进行动能分析，得到了进一步的详细信息。少

As well as the study of the multiply excited ionic states, i.e., the photoionization satellites, the study of molecular highly excited states excited by the photoabsorption of the energy above ca. 25 eV is quite improtant from the view point of the chemistry of highly excited molecules accompanying the electron correlation effect. The purpose of the present investigation has been to delope the spectroscopic method to identify and to observe the production and decay processes of such molecular highly excited states through the coincident measurments of the fragment photoions with the fluorescence from electronically excited neutral fragments. As shown below the purpose of the present investagation has been well accomplished.The present investigation has been carried out through the constructioin of the above mentioned experimental apparatus, nemely, a coincidence spectrometer, which is composed of a pulsed electromagnetic gas nozzle, a fluorescence detector, and a time-of-flight mass an … More alyzer and installed in a presently available highly evacuated vacuum chamber for collision of gas phase molecules with an extreme-ultraviolet photon beam. By developing, tuning, and using this apparatus, the investigation of entitled study has been performed for the tyipical diatomic molecules, such as hydrogen and nitrogen, by employing the monochromatized synchortron radiation at the Photon Factroy, the National Laboratory for High Energy Physics, Tsukuba.As for the results for nitrogen, the highly excited ions dissociating into a fragment ion (N^+) and an electronically excited neutral fragment (N^<**>) has been shown to correspond to the ions produced by the emission of electron from an inner valence orbital, with which almost no information was obtained previously. The detailed measurements of coincinent excitation funtin of fragment ions with fluorescence photons as a function of excitation photon energy have been performed. Also it has been successfully performed to reveal the production of ionic states with various symmetries the angular dependent coinicidence spectroscopy with respect to the polarization axis of synchrotron radiation. These have been the clear evidence showing the strong correlation between the one-electron ionic states and the multiply excited neutral molecules. Based on this rsult, the measurement of dispersed fluorescnce has been perfomed. It has been shown that a significant contribution of the fluorescence from ionic fragments is involved and that a certain molecular ionic state correlates to a certain fragment pair.As for the results for hydrogen, the coincidence spectra have shown that the one-electron ionic states with another one-electron excitetaion dissociate into a H^+ and a H^<**>, for which a detailed investigation has been performed by the measurements two dimensional coincidence spectroscopy. Further detailed information has been obtaine by the kinetic energy analysis of fragment ions using an electrostatic analyzer. Less