稀土—铱—锑合金热电材料的结构与量子化学计算研究

QUANTUM CHEMISTRY STUDY ON STRUCTURAL CHARACTERISTICS OF THERMOELECTRICS OF RARE EARTH-Ir-Sb ALLOYS

应用离散变分Xα 量子化学计算方法 ,研究了IrSb3,Ir4 NdGe3Sb9和Ir4 SmGe3Sb9三个skutterudites的组成、结构、化学键和热电性能之间的关系。对Ir4 NdGe3Sb9和Ir4 SmGe3Sb9,用多个模型研究了稀土元素振动的结构。计算结果表明 ,稀土原子靠近Ge原子的模型比靠近Sb原子的模型更为稳定 ,热导率也较低。Ir4 NdGe3Sb9的共价键比Ir4 SmGe3Sb9弱 ,Ir4 NdGe3Sb9和Ir4 SmGe3Sb9的共价键又比IrSb3弱 ,与热导率的实验测量结果一致。

The correlation among composition, structure, chemical bond and thermoelectric property of skutterudites of IrSb 3, Ir 4NdGe 3Sb 9 and Ir 4SmGe 3Sb 9 is studied using SCF\|DV\|X α method, one of calculation methods in quantum chemistry. Ir 4NdGe 3Sb 9 and Ir 4SmGe 3Sb 9 are calculated with several models for investigating the “rattling” patterns. The results show that the model with rare earth near to Ge is more stable than that with rare earth near to Sb, and the former is with lower thermal conductivity. The covalent bonds of Ir 4SmNdGe 3Sb 9 are weaker than those of Ir 4SmGe 3Sb 9, and those of Ir 4NdGe 3Sb 9 and Ir 4SmGe 3Sb 9 are both weaker than those of IrSb 3, which is consistent with the experimental result of thermal conductivity. [