First‐principles and molecular‐dynamics study of structure and bonding in perovskite‐type oxynitrides ABO2N (A = Ca, Sr, Ba; B = Ta, Nb)
First‐principles and molecular‐dynamics study of structure and bonding in perovskite‐type oxynitrides ABO2N (A = Ca, Sr, Ba; B = Ta, Nb)
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DOI：
10.1002/jcc.20895
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发表时间：
2008-10
影响因子：
3
通讯作者：
H. Wolff;R. Dronskowski
中科院分区：
文献类型：
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作者：
H. Wolff;R. Dronskowski
用第一性原理电子结构计算和分子动力学模拟方法研究了碱土基钽和铌氧化物的一系列钙钛矿型相，特别是从总能量计算的角度考察了不同的结构排列和阴离子分布。在COHP化学键分析和半经验分子轨道计算的基础上对其结构性质进行了解释。我们对这一令人惊讶的结果提供了理论证明，即这些相的局域位置对称性低于立方，因为密度泛函计算清楚地表明，所有的晶体单胞都可以更好地描述为具有Pmc21空间群的正交结构，以优化金属-氮键；然而，这与采用Pm\bar{3}$m空间群的BaTaO2N和BaNbO2N结构的宏观立方描述并不矛盾。此外，我们还发现，在较宽的温度范围内，所有所研究的化合物中的阴离子亚晶格都是有序的。#2008威利期刊，Inc.《康普特化学》，2008
A series of perovskite‐type phases of alkaline‐earth‐based tantalum and niobium oxynitrides has been studied using both first‐principles electronic‐structure calculations and molecular‐dynamics simulations, in particular by investigating different structural arrangements and anion distributions in terms of total‐energy calculations. The structural properties are explained on the basis of COHP chemical bonding analyses and semiempirical molecular orbital calculations. We provide theoretical proof for the surprising result that the local site symmetries of these phases are lower than cubic because density‐functional calculations clearly show that all crystallographic unit cells are better described as being orthorhombic with space group Pmc21 to optimize metal–nitrogen bonding; nonetheless, there is no contradiction with a macroscopic cubic description of the structures of BaTaO2N and BaNbO2N adopting space group Pm$\bar{3}$m. Additionally, we find that the anionic sublattice is ordered in all compounds studied over a wide temperature range. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008