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Study on Multielectron Effect Near Molecular Inner-Shell Photoionization Thresholds

分子内壳光电离阈值附近的多电子效应研究

基本信息

批准号：
15340135
负责人：
SHIGEMASA Eiji
金额：
$ 7.1万
依托单位：
Institute for Molecular Science (2004-2005)Okazaki National Research Institutes (2003)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

The double toroidal analyzer (DTA) at UVSOR, which has been originally developed by a French group, has been under conditioning. The imaging detection without any exit slit enables us to observe electrons within an energy range more than 10% of the pass energy, and their angular distributions simultaneously. Recently it was confirmed that the performance of the analyzer has been improved considerably, after re-assembling of DTA and its careful tuning. The introduction of an ion time-of-flight spectrometer with a two dimensional detector is in the planning stage, to perform energy-selected-electron-ion coincidence experiments.Parallel to the research and development of new experimental setups, some trial experiments have been made for observing minor products, such as highly excited neutral species and anions after the molecular inner-shell excitations. A strong enhancement due to the N^* formation has been observed around the 1s threshold of N_2 molecules. It has been found that the highly excited N_2^<+^*> states leading to the N^* formation are populated by spectator Auger decay from the core-excited states, as well as by the recapture of slow photoelectrons into the Rydberg orbitals. It turns out that the metastable observation is a new and sensitive tool to study the decay dynamics of core-excited states and the photoelectron recapture due to the post-collision interaction. Concerning the anion imaging detection after the molecular inner-shell excitations, we have confronted difficulty in eliminating a large background noise by electrons, which may be fixed by performing time-resolved experiments.

UVSOR 的双环形分析仪 (DTA) 最初由一家法国集团开发，现已进行调试。无出口狭缝的成像检测使我们能够同时观察超过通过能量10%的能量范围内的电子及其角分布。最近证实，经过DTA的重新组装和仔细调整后，分析仪的性能得到了显着提高。正在规划引入带有二维探测器的离子飞行时间光谱仪，以进行能量选择电子离子符合实验。在研究和开发新的实验装置的同时，还进行了一些试验实验，用于观察分子内壳层激发后的高激发中性物种和阴离子等次要产物。在 N_2 分子的 1s 阈值附近观察到由于 N^* 形成而产生的强烈增强。已经发现，导致 N^* 形成的高度激发的 N_2^<+^*> 态是通过来自核心激发态的观察者俄歇衰变以及慢速光电子重新捕获到里德伯轨道而填充的。事实证明，亚稳态观测是研究核激发态衰变动力学和碰撞后相互作用引起的光电子重捕获的一种新的、灵敏的工具。关于分子内壳层激发后的阴离子成像检测，我们面临着消除电子大背景噪声的困难，这可以通过进行时间分辨实验来解决。