Lithium boro-hydride LiBH4II.: Raman spectroscopy
Lithium boro-hydride LiBH4II.: Raman spectroscopy
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DOI：
10.1016/s0925-8388(02)00668-0
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发表时间：
2002-11-18
影响因子：
6.2
通讯作者：
Yvon, K
中科院分区：
文献类型：
--
作者：
Gomes, S;Hagemann, H;Yvon, K
在295-412 K温度区间和2700-130 cm（-1）频率范围内用拉曼光谱研究了多晶LiBH_4。的拉曼活动模式是一致的存在下，（BH 4）（-）离子具有扭曲的四面体配置。随着温度的升高，模式分裂的突然消失表明结构相变的开始，导致（BH 4）（-）四面体的更高的局部对称性。该相变发生在384 K附近，为一级相变，滞后约为8 K。一个强大的和不连续的扩大后，过渡带剩余的建议开始大的振动振幅的（BH 4）（-）四面体围绕他们的三角轴。(C)2002 Elsevier Science B. V.保留所有权利。
Polycrystalline LiBH4 has been studied by Raman spectroscopy in the temperature interval 295-412 K and the frequency range 2700-130 cm(-1). The Raman active modes are consistent with the presence of a (BH4)(-) ion having a distorted tetrahedral configuration. As the temperature is increased the sudden disappearance of mode splitting points to the onset of a structural phase transition that leads to a higher local symmetry of the (BH4)(-) tetrahedron. The transition occurs at similar to384 K, is of first-order and has a hysteresis of about 8 K. A strong and discontinuous broadening of bands remaining after the transition suggests the onset of large vibrational amplitudes of the (BH4)(-) tetrahedra about their trigonal axis. (C) 2002 Elsevier Science B.V. All rights reserved.