Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland.
J Synchrotron Radiat. 2011 Nov;18(Pt 6):851-61. doi: 10.1107/S0909049511030688. Epub 2011 Sep 15.
Projections of the atomic structure around Nb atoms in a LiNbO(3) single crystal were obtained from a white-beam X-ray absorption anisotropy (XAA) pattern detected using Nb K fluorescence. This kind of anisotropy results from the interference of X-rays inside a sample and, owing to the short coherence length of a white beam, is visible only at small angles around interatomic directions. Consequently, the main features of the recorded XAA corresponded to distorted real-space projections of dense-packed atomic planes and atomic rows. A quantitative analysis of XAA was carried out using a wavelet transform and allowed well resolved projections of Nb atoms to be obtained up to distances of 10 Å. The signal of nearest O atoms was detected indirectly by a comparison with model calculations. The measurement of white-beam XAA using characteristic radiation indicates the possibility of obtaining element-sensitive projections of the local atomic structure in more complex samples.
从使用铌 K 荧光探测到的白光束 X 射线吸收各向异性（XAA）模式中，得到了 LiNbO(3)单晶中铌原子周围原子结构的投影。这种各向异性源于样品内部 X 射线的干涉，由于白光束的相干长度较短，仅在原子方向附近的小角度处可见。因此，记录的 XAA 的主要特征对应于密集堆积的原子平面和原子行的扭曲实空间投影。使用小波变换对 XAA 进行了定量分析，允许获得高达 10 Å 的距离的铌原子的分辨率良好的投影。通过与模型计算的比较，间接检测到最近的 O 原子的信号。使用特征辐射测量白光束 XAA 表明，在更复杂的样品中获得局部原子结构的元素敏感投影是可能的。
