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Development of a method for imaging molecular orbital pattern and foundation of momentum spectroscopy

分子轨道模式成像方法的发展和动量谱的基础

基本信息

批准号：
16205006
负责人：
TAKAHASHI Masahiko
金额：
$ 31.03万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2007
项目状态：
已结题

项目摘要

Various kinds of molecular properties such as reactivity are governed by molecular orbital pattern of a specific valence electron. The purpose of this project is to develop a method for imaging such molecular orbital pattern in momentum space.In order to realize this project, we have constructed an apparatus that aims to detect in triple coincidence the two outgoing electrons and the fragment ion produced by electron Compton scattering and to measure vector correlations among the three charged particles. The apparatus has been subsequently employed for dissociative ionization processes of the H_2 and O_2 molecules. Although the experimental results suffer from rather large statistical uncertainties, they are found to fulfill our expectations. For instance, the 2_<Sδ_g> electron orbital of the H_2 molecule has been observed in momentum space as what is elongated in the direction perpendicular to the molecular axis, which is well known to be stretched along the molecular axis in position space. This observation is due entirely to nature of Fourier transform. On the other hand, for the 2_<Pδ_u> orbital of the molecule, the p-type orbital nature, which lobes and a nodal plane lie in the direction parallel and perpendicular to the molecular axis respectively, has been clearly observed. In this way, we have successfully demonstrated for the first time that looking at molecular orbitals in the three dimensional form is totally possible.The achievements of this project has been highly evaluated as pioneering work for molecular orbital imaging, opening the door for detailed studies on bound electronic wave functions of molecules. This work has been invited to a broad range of international and domestic conferences (40 invited talks) and The Chemical Society of Japan (CSJ) Award for Creative Work has been provided to the head investigator in 2008 March.

各种分子特性（例如反应性）由特定价电子的分子轨道模式控制。该项目的目的是开发一种在动量空间中对此类分子轨道模式进行成像的方法。为了实现该项目，我们构建了一种装置，旨在检测三重重合的两个出射电子和电子康普顿散射产生的碎片离子，并测量三个带电粒子之间的矢量相关性。该装置随后被用于H_2和O_2分子的解离电离过程。尽管实验结果存在相当大的统计不确定性，但它们符合我们的预期。例如，H_2分子的2_<Sδ_g>电子轨道在动量空间中被观察为在垂直于分子轴的方向上被拉长，众所周知，其在位置空间中沿着分子轴被拉长。这一观察结果完全归因于傅里叶变换的性质。另一方面，对于分子的2_<Pδ_u>轨道，可以清楚地观察到p型轨道性质，其波瓣和节面分别位于平行于分子轴的方向和垂直于分子轴的方向。这样，我们首次成功证明了以三维形式观察分子轨道是完全可能的。该项目的成果被高度评价为分子轨道成像的开创性工作，为详细研究分子束缚电子波函数打开了大门。该工作已被邀请参加广泛的国际和国内会议（40次特邀报告），并于2008年3月向首席研究员颁发了日本化学会（CSJ）创造性工作奖。