Evans John
School of Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
Phys Chem Chem Phys. 2006 Jul 14;8(26):3045-58. doi: 10.1039/b604369k. Epub 2006 May 24.
Third generation synchrotron light sources provide stable, tuneable light of energy up to the hard X-ray region. The gain of a trillion in brightness as compared to a conventional laboratory X-ray source transforms the opportunities for establishing structure-function relationships. The light may be quasi-continuous or pulsed, have controllable polarisation and have coherence lengths larger than the sample size. The high brightness provides a basis for adding time and spatial resolution to X-ray scattering and spectroscopy. It may also be used to identify very specific information about the magnetic properties of atoms within materials, element specific vibrations, and local structural descriptions identified with chemical speciation. More demanding scattering and diffraction problems can be solved such as weakly scattering materials, large unit cells and structural entities. The high collimation of the source also provides enhanced spectroscopic and diffraction resolution that gives more insight into molecular, extended and supramolecular structures. The length scales can be bridged from the atomic up to that of visible light microscopy and buried features within materials can be observed with the appropriate energy. With an increased emphasis on ease of use, such capabilities are open to exploitation for chemical challenges.
第三代同步辐射光源可提供稳定、可调谐的光,其能量可达硬X射线区域。与传统实验室X射线源相比,亮度提高了万亿倍,这改变了建立结构-功能关系的机会。这种光可以是准连续的或脉冲的,具有可控的偏振,并且相干长度大于样品尺寸。高亮度为在X射线散射和光谱学中增加时间和空间分辨率提供了基础。它还可用于识别有关材料中原子磁性特性、元素特定振动以及通过化学形态确定的局部结构描述的非常具体的信息。可以解决更具挑战性的散射和衍射问题,例如弱散射材料、大晶胞和结构实体。光源的高准直性还提供了更高的光谱和衍射分辨率,从而能更深入地了解分子、扩展和超分子结构。长度尺度可以从原子尺度跨越到可见光显微镜尺度,并且可以利用适当的能量观察材料内部的隐藏特征。随着对易用性的日益重视,这些能力可用于应对化学挑战。