X ray inelastic scattering spectroscopy for electron momentum density in solids

康普顿散射测量是研究物质中电子动量密度分布的一种独特方法。这项工作主要在光子工厂，国家高能物理实验室完成。得到的结果如下：1。一个高分辨率康普顿光谱仪，用于29.5keV入射X射线。已在14C号梁线建成。它由一个弯晶单色仪，一个用于康普顿散射X射线能量分析的Cauchois型晶体分析仪和一张作为位置敏感探测器的成像板组成。动量分辨率为0.09原子单位。用这种方法测量了Si、Al和液态Li、Na、Li-Na合金的康普顿曲线。得到了有关能带结构和电子-电子相关效应的信息。测定了LiH、Li_2O和Li_3N的康普顿谱，得到了这些化合物的成键电子信息。在束线AR-NE1上，另一个更先进的光谱仪已经建成。该仪器用于40-80keV入射X射线，由准双弯曲单色仪和四对Cauchois型分析仪和成像板组成。有了这个康普顿轮廓沿四个不同的结晶轴可以同时测量。三维电子动量密度图可以根据沿不同结晶轴的轮廓重建，从而获得金属和合金中能带结构和费米表面几何形状的详细信息。测量了Fe和Ni单晶的电子自旋相关康普顿谱，并与带理论结果进行了比较。所得结论之一是这些金属中磁性电子的动量波函数可以用能带理论很好地描述。研究表明，椭圆极化同步辐射X射线对研究铁磁材料的磁性是非常有用的。

Compton scattering measurement is a unique method to study electron momentum density distributions in matter. This work has been done mostly at Photon Factory, National Laboratory for High Energy Physics. The results obtained are as follows;1. A high resolution Comptonspectrometer for 29.5keV incident X rays.has been constructed at Beam Line 14C. It consists of a bent crystal monochromator, a Cauchois type crystal analyzer for energy analysis of Compton scattered X rays and a sheet of Imaging Plate as a position sensitive detector. The momentum resolution is 0.09 atomic units. With this Compton profiles of Si, Al and liquid Li, Na, Li-Na alloy were measured. Information on the band structure and the effects of electron-electron correlation has been obtained. The Compton profiles of LiH, Li_2O,and Li_3N were also measured and information on the bonding electrons in these compounds has been obtained.2. At Beam Line AR-NE1 another more advanced spectrometer has been constructed. This one is for 40-80keV incident X rays and consists of a quasi doubly bent monochromator and four pairs of Cauchois type analyzer and Imaging Plate. With this Compton profiles along four different crystalline axes can be measured simultaneously. The three dimensional electron momentum density map can be reconstructed from the profiles taken along various crystalline axes to get much detailed information on the band structure and the Fermi surface geometry in metals and alloys.3. Electron-spin dependent Compton profiles of Fe and Ni single crystals were measured and compared with the band theoretical results. One of the conclusions obtained is that the momentum-wavefunctions of the magnetic electrons in these metals are well described by the band theory. It has been demonstrated that elliptically polarized synchrotron radiation X rays are quite useful to study magnetic properties of ferromagnetic materials.