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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 relationship between the composition, structure, chemical bond and thermoelectric properties of three skutterudites, IrSb3, Ir4 NdGe3Sb9 and Ir4 SmGe3Sb9, has been studied by means of discrete variational Xα quantum chemistry calculation. The structure of rare earth element vibration has been studied by using multiple models for Ir4 NdGe3Sb9 and Ir4 SmGe3Sb9. The calculated results show that the model of rare earth atoms close to Ge atoms is more stable than the model close to Sb atoms and the thermal conductivity is also lower. The covalent bond of Ir4 NdGe3Sb9 is weaker than that of Ir4 SmGe3Sb9, and the covalent bond of Ir4 NdGe3Sb9 and Ir4 SmGe3Sb9 is weaker than that of IrSb3, which is consistent with the experimental measurement of thermal conductivity.