d-d Spectra of transition-metal carbodiimides and hydrocyanamides as derived from many-particle effective Hamiltonian calculations.
d-d Spectra of transition-metal carbodiimides and hydrocyanamides as derived from many-particle effective Hamiltonian calculations.
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过渡金属碳二亚胺和氢氰胺的 d-d 光谱，源自多粒子有效哈密顿量计算。
DOI：
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发表时间：
2011
影响因子：
2.9
通讯作者：
R. Dronskowski
中科院分区：
文献类型：
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作者：
A. Tchougréeff;R. Dronskowski
采用晶场有效哈密顿量的局域多粒子方法(EHCF)分析了M=Fe-Ni过渡金属碳化二亚胺化合物的磁基态和低能激发光谱。实验上，这些材料代表了一组均匀的(高自旋)反铁磁、光学透明的有色绝缘体，在可见光光谱中有吸收线。这些发现得到了EHCF数值模拟的充分支持。在这三种情况下，我们都得到了高自旋基态，这与以前的磁测量结果以及可见吸收光谱中d-d内壳层跃迁的存在是一致的。值得注意的是，EHCF方法解决了有争议的FeNCN的情况，即使在包括显式电子关联(GGA+U)的情况下，密度泛函理论也预测FeNCN是金属的。我们还研究了通式为M(NCNH)(2)的过渡金属氢氰胺的基态和低能激发光谱，其中M=Fe-Ni，这是另一组均匀的光学透明有色绝缘体。EHCF也到达高自旋基态和可见的d-d壳内跃迁。
We apply the local many-particle method of the Effective Hamiltonian of Crystal Field (EHCF) to analyze the magnetic ground state and the low-energy excitation spectra of the transition-metal carbodiimides MNCN with M = Fe-Ni. Experimentally, these materials represent a uniform group of (high-spin) antiferromagnetic, optically transparent, colored insulators with absorption lines in the visible spectrum. These findings are fully supported by the EHCF numerical modeling. In all three cases, we arrive at high-spin ground states in agreement with the results of previous magnetic measurements as well as the presence of the d-d intrashell transitions for the visible absorption spectra. Remarkably enough, the EHCF approach resolves the controversial case of FeNCN which was earlier predicted to be metallic by density-functional theory even when including explicit electronic correlation (GGA+U). We also address the ground state and the low-energy excitation spectra of the transition-metal hydrocyanamides of the general formula M(NCNH)(2) with M = Fe-Ni, another uniform group of optically transparent colored insulators. EHCF also arrives at high-spin ground states and visible d-d intrashell transitions.