Abstract

Within the density functional theory, ab initio calculation of the crystal structure, phonon spectrum, and elastic properties of lanthanum germanate La₂Ge₂O₇ with triclinic structure (space group \(P\bar {1}\), no. 2). Frequencies and types of fundamental vibrations are determined. The degree of involvement of ions in each mode is determined by analyzing calculated displacement vectors. The calculations are performed for the first time. Experimental data on IR and Raman spectra, as well as elastic constants of La₂Ge₂O₇ are absent in the literature. The program CRYSTAL17 intended for ab initio calculations of periodic structures within the MO LCAO (molecular orbital as a linear combination of atomic orbitals) approach is used.

中文翻译：

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La2Ge2O7 的声子谱：Ab Initio 计算

摘要

在密度泛函理论中，从头计算具有三斜晶系结构的锗酸镧La ₂ Ge ₂ O ₇的晶体结构、声子光谱和弹性特性（空间群\(P\bar {1}\)，第2号） . 确定基本振动的频率和类型。通过分析计算出的位移矢量来确定离子在每个模式中的参与程度。计算是第一次执行。红外和拉曼光谱的实验数据，以及 La ₂ Ge ₂ O _{7的弹性常数}文献中没有。使用旨在从头计算MO LCAO（作为原子轨道的线性组合的分子轨道）方法内的周期性结构的程序CRYSTAL17。