Surface structure and surface states in magnesium oxide powders
Surface structure and surface states in magnesium oxide powders
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DOI：
10.1039/f19797501769
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发表时间：
1979-10
期刊：
影响因子：
--
通讯作者：
S. Coluccia;A. J. Tench;R. Segall
中科院分区：
文献类型：
--
作者：
S. Coluccia;A. J. Tench;R. Segall
将MgO烟气的光致发光光谱和反射光谱与MgO的除氢氧化物和除碳酸盐光谱进行了比较。电子显微镜的平行研究表明，光谱与通过不同途径获得的粒子的不同形态之间存在很强的相关性。观察到的光谱与氧化物颗粒的表面有关，激发和吸收带与氧离子的3和4倍配位有关。所有样品中都存在相同类型的位点，但配位最低的离子在接近完美的MgO烟雾立方体上的含量要少得多。在暴露于水蒸气中数小时后，烟雾颗粒上的3倍配位位点数量显著增加。这幅图与电子显微图一致，电子显微图显示了经水蒸气处理后MgO烟雾的边缘和角落的侵蚀。一个涉及到离子对被水从立方体的角落和边缘去除的模型显示出最低配位位置的观察到的增加。
The photoluminescent and reflectance spectra of MgO smoke have been compared with the spectra of MgO ex-hydroxide and ex-carbonate. Parallel studies by electron microscopy have shown that a strong correlation exists between the optical spectra and the different morphology of the particles obtained by the different routes. The spectra observed are associated with the surface of the oxide particles and the excitation and absorption bands are associated with oxygen ions in 3- and 4-fold coordination. The same kinds of sites are present on all samples but the ions of lowest coordination are much less abundant on the nearly perfect cubes of MgO smoke. The number of 3-fold coordinated sites on the smoke particles is considerably increased after exposure to water vapour for several h. This picture is consistent with the electron micrographs which show erosion of the edges and corners of the MgO smoke after treatment with water vapour. A model involving the removal of ion pairs from the corners and edges of the cube by water is shown to give the observed increase in the sites of lowest coordination.