阿伏加德罗常数测量研究最新进展

Progress in the Determination of the Avogadro Constant

综述了阿伏加德罗常数（NA）测量研究的最新进展。介绍了目前测NA准确度较高的方法-x射线晶体密度法，该方法通过测量单晶硅的摩尔质量、宏观密度和晶格常数得到NA。采用x射线晶体密度法有望实现NA相对测量不确定度达到2×10^-8。分析了当前限制NA测量准确度提高的关键研究内容：单晶硅摩尔质量、硅球直径和表面氧化层厚度的测量。并展望了NA测量未来的工作方向。

The progress in the determination of the Avogadro constant （NA ） is reviewed. The x-ray crystal density method is considered as one of the most accurate route to determine NA. According to this method, the molar mass, density and lattice parameter of the single crystal silicon could be measured accurately, then a relative measurement uncertainty 2×10^-8 of NA is achievable. The determination of the molar mass, the diameter of the silicon sphere, and the thickness of the oxide layer on the silicon sphere are key issues that affect the measurement accuracy of NAcurrently,and the focal points for further reseach of the datermination NA is presented.