Coppens Philip, Fournier Bertrand
Chemistry Department, University at Buffalo, State University of New York, Buffalo, NY 14260-3000, USA.
J Synchrotron Radiat. 2015 Mar;22(2):280-7. doi: 10.1107/S1600577514026538. Epub 2015 Jan 28.
Newly developed methods for time-resolved studies using the polychromatic and in particular the pink-Laue technique, suitable for medium and small-size unit cells typical in chemical crystallography, are reviewed. The order of the sections follows that of a typical study, starting with a description of the pink-Laue technique, followed by the strategy of data collection for analysis with the RATIO method. Novel procedures are described for spot integration, orientation matrix determination for relatively sparse diffraction patterns, scaling of multi-crystal data sets, use of Fourier maps for initial assessment and analysis of results, and least-squares refinement of photo-induced structural and thermal changes. In the calculation of Fourier maps a ground-state structure model, typically based on monochromatic results, is employed as reference, and the laser-ON structure factors for the Fourier summations are obtained by multiplying the reference ground-state structure factors by the square root of the experimental ON/OFF ratios. A schematic of the procedure followed is included in the conclusion section.
本文综述了新开发的用于时间分辨研究的方法，这些方法采用多色光，特别是粉红劳厄技术，适用于化学晶体学中典型的中小尺寸晶胞。各章节的顺序遵循典型研究的顺序，首先描述粉红劳厄技术，然后是使用RATIO方法进行分析的数据收集策略。文中描述了用于斑点积分、相对稀疏衍射图样的取向矩阵确定、多晶体数据集的缩放、使用傅里叶图进行结果的初步评估和分析以及光致结构和热变化的最小二乘精修的新程序。在计算傅里叶图时，通常基于单色结果的基态结构模型用作参考，并且通过将参考基态结构因子乘以实验开/关比的平方根来获得用于傅里叶求和的激光开启结构因子。结论部分包含了所遵循程序的示意图。
