Wavefuntion in Momentum Space and Molecular Recognition

本研究项目旨在利用电子动量谱（EMS）测定分子在动量空间中的波泛函形式。电子能谱利用了由电子碰撞引起的非弹性电子散射和分子的电离跃迁。可以确定单个轨道的波函数形式，并通过傅里叶变换得到实（位）空间的波函数。进一步的目的是了解分子识别的机制，从波函数形式的轨道，如H0M0。该方法的难点在于散射截面小，导致数据积累周期长，但信噪比低，难以获得定量数据。为了克服这一困难，我们利用二维探测器构造了一种新的光谱仪。该仪器的主要部件是在东北大学IMRAM的机械车间制造的。2001财政年度的预算主要用于建造光谱仪的材料。结果，我们成功地显著提高了检测效率。通过使用新建成的光谱仪，在2002财政年度挑战了以下主题。利用电子动量分布的冲击能依赖性表征乙二醛和双乙酰基的homo和NHOMOco3的高激发态。氢分子离子的高激发态。N_2O外轨道动量分布。目前，正在对该腔室进行改造，以便配备高温喷嘴，从而可以将靶标扩展到具有低蒸气压的低分子分子，如甘氨酸和腺嘌呤。

The present research project aims at determination of wavefunctional forms of molecules in the momentum space by the use of electron momentum spectroscopy(EMS). EMS makes use of inelastic electron scattering accompanied with ionization transition of molecules induced by electron collision. It is possible to determine wavefunctional form of individual orbitals, and through the Fourier transformation wavefunction of real (position) space can be obtained. Further aimed at is to understand the mechanism of molecular recognition in terms of the wavefunctional forms of orbitals such as H0M0.The difficulties of this EMS lies in small scattering cross section, which results in low signal to noise ratio in spite of a long data-accumulation period, and hence it is very difficult to obtain quantitative data. In crder to overcome this difficulty we have constructed a new spectrometer by making use of two-dimensional detector. The major parts of this instrument were manufactured at the machine shop of the IMRAM, Tohoku University. The budget of the fiscal year 2001 was mainly appropriated for the materials to construct the spectrometer. As a result, we have succeeded in improving the detection efficiency significantly.By using the newly built spectrometer, the following topics have been challenged in the fiscal year 2002.1. Characterization of H0M0 and NHOMO of glyoxal and biacetyl through impact energy dependence of electron momentum distribution.2. Higher excited states of CO.3. Higher excited states of Hydrogen molecular ion4. Momentum distribution of outer orbitals of N_2O.At present, the chamber is being modified in order to be equipped with high-temperture nozzle, which makes it possible to extend the target to molecules with low molecules with low vapor pressure, such as glycine and adenine.