Sasaki Tomoaki, Kasai Hidetaka, Nishibori Eiji
Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, 305-8571, Japan.
Faculty of Pure and Applied Sciences and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, Tsukuba, 305-8571, Japan.
Sci Rep. 2018 Aug 10;8(1):11964. doi: 10.1038/s41598-018-30470-1.
Accurate and high reciprocal resolution experimental structure factors of aluminum were determined from a synchrotron powder X-ray diffraction data measured at 30 K with sin θ/λ < 2.31 Å. The structure factors have small deviations from independent atom model in sin θ/λ < 0.83 Å. Theoretical structure factors were prepared using density functional theoretical calculations by full potential linearized augmented plane wave method. The deviation between experimental and theoretical data was also observed at around sin θ/λ ≈ 0.4 Å. The charge density was determined by an extended Hansen-Coppens multipole modeling using experimental and theoretical structure factors. Charge density maxima at tetrahedral site were observed in both experimental and theoretical deformation density. The charge-density difference peaks indicating directional bonding formation were observed in the difference density between experiment and theory. The present study reveals tight binding like character of valence electron of aluminum. The fact will provide a crucial information for development of high-performance aluminum alloy.
利用在30K下测量的同步辐射粉末X射线衍射数据，在sin θ/λ < 2.31 Å的条件下，确定了铝的精确且高互易分辨率的实验结构因子。在sin θ/λ < 0.83 Å时，结构因子与独立原子模型的偏差较小。使用全势线性缀加平面波方法通过密度泛函理论计算制备了理论结构因子。在sin θ/λ ≈ 0.4 Å附近也观察到了实验数据与理论数据之间的偏差。通过使用实验和理论结构因子的扩展汉森 - 科彭斯多极模型确定了电荷密度。在实验和理论变形密度中均观察到四面体位置处的电荷密度最大值。在实验与理论的差异密度中观察到了表明定向键形成的电荷密度差异峰。本研究揭示了铝价电子类似紧密结合的特性。这一事实将为高性能铝合金的开发提供关键信息。
