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首页> 外文期刊>Acta Crystallographica, Section B. Structural science, crystal engineering and materials >Structure factors and charge-density study of diamond at 800 K
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Structure factors and charge-density study of diamond at 800 K

机译：800 k钻石的结构因素和电荷密度研究

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摘要

The structure factors of diamond were determined by synchrotron radiation X-ray powder diffraction at 800 K at sin θ/λ ≤ 2.2 ?~(-1) reciprocal resolution. The structure factors were estimated using six powder profiles measured on beamline BL02B2 at SPring-8 (Hyogo, Japan). A high reciprocal resolution at sin θ/λ ≤ 2.2 ?~(-1) was required to reveal the temperature dependence of the charge density, due to the high Debye temperature of θ_D = 1860 K of diamond. Wide 2θ angle data with the highest counting statistics are crucial for accurate data analysis. The periodic noise of every six-pixel step was observed in the highest counting statistics imaging plate (IP) data scanned by a BAS2500 IP scanner. It was found that the noise originated from the six-sided polygonal mirror in the scanner. The intensity fluctuation at every six-pixel step was also found in the Fourier series expansion of the powder profiles. The ratio of the maximum fluctuation was estimated as 0.4% by summing all six-pixel step data. The powder profiles were corrected by multiplying the ratios. The intensity fluctuation in the background region was reduced to less than 50% of the uncorrected data. The weak 888 Bragg reflection, with an intensity of 0.005% of that of the 111 Bragg reflection at 800 K, was readily observed in the corrected data. Finally, the structure factors determined at 800 K were successfully applied to a charge-density study by multipole modelling. The reliability factors and multipole parameters at 800 K are in agreement with those at 300 K. The differences in the charge density at the bond midpoint and ?_p~2 at the bondcritical point were less than 1% and 2%, respectively.
机译：钻石的结构因素由同步辐射X射线粉末衍射在SINθ/λ≤2.2Ω·（-1）互易分辨率下以800 k处确定。在Spring-8（日本兵库）在梁线BL02B2上测量的六个粉末轮廓估计了结构因素。由于θ_d= 1860k的金刚石的高德比温度，需要在SINθ/λ≤2.2Ω≤2.2Ω≤2.2≤2≤2.2≤2.2≤2.2Ω·（-1）的高往复分辨率。具有最高计数统计数据的宽2θ角度数据对于准确的数据分析至关重要。在BAS2500 IP扫描仪扫描的最高计数统计成像板（IP）数据中观察每个六像素步骤的周期性噪声。发现噪声来自扫描仪中的六面多边形镜。在粉末轮廓的傅里叶串联膨胀中也发现了每六个像素步骤的强度波动。通过求和所有六像素步长数据估计最大波动的比率为0.4％。通过乘以比率来校正粉末型材。背景区域中的强度波动降低到未校正数据的小于50％。在校正的数据中容易观察到弱888布拉格反射，强度为800 k的111布拉格反射的0.005％。最后，通过多极型建模成功地应用于800 k的结构因子。 800 k的可靠性因素和多极参数与300k时的那些达成一致。债券中点的电荷密度的差异分别小于1％和2％。

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