碱钙三氢化物的结构研究与热力学性质。

Structural investigation and thermodynamical properties of alkali calcium trihydrides.

机构信息

Department of Chemistry, Center for Materials Sciences and Nanotechnology, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway.

出版信息

J Chem Phys. 2010 Mar 21;132(11):114504. doi: 10.1063/1.3299732.

DOI:10.1063/1.3299732

PMID:20331302

Abstract

The ground-state structure, equilibrium structural parameters, electronic structure, and thermodynamical properties of MCaH(3) (M=Li, Na, K, Rb, and Cs) phases have been investigated. From the 104 structural models used as inputs for structural optimization calculations, the ground-state crystal structures of MCaH(3) phases have been predicted. At ambient condition, LiCaH(3), NaCaH(3), and KCaH(3) crystallize in hexagonal, monoclinic, and orthorhombic structures, respectively. The remaining phases RbCaH(3) and CsCaH(3) crystallize in a cubic structure. The calculated phonon spectra indicate that all the predicted phases are dynamically stable. The formation energy for the MCaH(3) phases have been calculated along different reaction pathways. The electronic structures reveal that all these phases are insulators with an estimated band gap varying between 2.5 and 3.3 eV.

摘要

研究了 MCaH(3)（M=Li、Na、K、Rb 和 Cs）相的基态结构、平衡结构参数、电子结构和热力学性质。从用作结构优化计算输入的 104 个结构模型中，预测了 MCaH(3)相的基态晶体结构。在环境条件下，LiCaH(3)、NaCaH(3)和 KCaH(3)分别结晶为六方、单斜和正交结构。其余相 RbCaH(3)和 CsCaH(3)结晶为立方结构。计算的声子谱表明，所有预测的相都是动态稳定的。通过不同的反应途径计算了 MCaH(3)相的形成能。电子结构表明，这些相都是具有 2.5 到 3.3 eV 之间的估计能带隙的绝缘体。