通过非弹性中子散射和第一性原理计算对SrGa2H2和BaGa2H2的振动性质研究

Vibrational property study of SrGa2H2 and BaGa2H2 by inelastic neutron scattering and first principles calculations.

作者信息

Lee Myeong H, Evans Michael J, Daemen Luke L, Sankey Otto F, Häussermann Ulrich

机构信息

Department of Physics, Arizona State University, P.O. Box 871504 Tempe, Arizona 85287-1504, USA.

出版信息

Inorg Chem. 2008 Mar 3;47(5):1496-501. doi: 10.1021/ic7019318. Epub 2008 Feb 1.

DOI:10.1021/ic7019318

PMID:18237114

Abstract

Vibrational properties of the gallium hydrides SrGa2H2 and BaGa2H2 have been investigated by means of inelastic neutron scattering (INS) and first-principles calculations. The compounds contain Ga-H units being part of a two-dimensional polyanionic layer, [(GaH)(GaH)]2-. The INS spectra are composed of dispersed internal Ga-H bending and stretching modes at frequencies above 600 cm(-1) and external lattice modes at frequencies below 220 cm(-1). Frequencies of the internal modes are not susceptible to the metal countercation, indicating a strong integrity of the polyanionic layer as a building unit in the structures of SrGa2H2 and BaGa2H2. The Ga-H stretching modes have frequencies between 1200 and 1400 cm(-1), which is very low compared to molecular gallium hydrides. The weak Ga-H bond in SrGa2H2 and BaGa2H2 is balanced by Sr(Ba)-H interactions.

摘要

通过非弹性中子散射（INS）和第一性原理计算研究了氢化镓化合物SrGa2H2和BaGa2H2的振动特性。这些化合物包含Ga-H单元，它们是二维聚阴离子层[(GaH)(GaH)]2-的一部分。INS光谱由频率高于600 cm(-1)的分散的内部Ga-H弯曲和拉伸模式以及频率低于220 cm(-1)的外部晶格模式组成。内部模式的频率对金属抗衡阳离子不敏感，这表明聚阴离子层作为SrGa2H2和BaGa2H2结构中的构建单元具有很强的完整性。Ga-H拉伸模式的频率在1200至1400 cm(-1)之间，与分子氢化镓相比非常低。SrGa2H2和BaGa2H2中较弱的Ga-H键通过Sr(Ba)-H相互作用得到平衡。