NanoScience Technology Center, Department of Mechanical, Material and Aerospace Engineering, University of Central Florida, 12424 Research Parkway, Ste 400, Orlando, FL 32826, USA.
J Mol Model. 2010 Oct;16(10):1617-23. doi: 10.1007/s00894-010-0671-2. Epub 2010 Mar 2.
We report plane wave basis density functional theory (DFT) calculations of the oxygen vacancies formation energy in nanocrystalline CeO2-x in comparison with corresponding results for bulk and (111) CeO2 surface. Effects of strong electronic correlation of Ce4f states are taken into account through the use of an effective on-site Coulomb repulsive interaction within DFT+U approach. Different combinations of exchange-correlation functionals and corresponding U values reported in the literature are tested and the obtained results compared with experimental data. We found that both absolute values and trends in oxygen vacancy formation energy depend on the value of U and associated with degree of localization of Ce4f states. Effect of oxygen vacancy and geometry optimization method on spatial spin distribution in model ceria nanoparticles is also discussed.
我们报告了平面波基密度泛函理论（DFT）计算的纳米晶 CeO2-x 中氧空位形成能，与体相和（111）CeO2 表面的相应结果进行了比较。通过在 DFT+U 方法中使用有效局域库仑排斥相互作用，考虑了 Ce4f 态的强电子相关。我们测试了文献中报道的不同的交换相关泛函和相应的 U 值的组合，并将得到的结果与实验数据进行了比较。我们发现，氧空位形成能的绝对值和趋势都取决于 U 值，并与 Ce4f 态的局域化程度有关。我们还讨论了氧空位和几何优化方法对模型氧化铈纳米粒子中空间自旋分布的影响。
