Spontaneous Raman spectroscopy of tungstate and molybdate crystals for Raman lasers
Spontaneous Raman spectroscopy of tungstate and molybdate crystals for Raman lasers
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DOI：
10.1016/s0925-3467(00)00037-9
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发表时间：
2000-12-01
影响因子：
3.9
通讯作者：
Zverev, PG
中科院分区：
文献类型：
--
作者：
Basiev, TT;Sobol, AA;Zverev, PG
研究了具有层状结构的钨酸盐（MeWO4）和钼酸盐（MeMoO4）晶体（Me = Ca, Sr, Ba, Pb）的自发拉曼光谱。利用高温拉曼光谱技术，在77 K至熔点温度范围内测量了内部振动模式的能移和谱线展宽。在1600k温度下，发现BaMo04晶体由板状结构向立方结构转变。基于熔融态钨酸盐和钼酸盐晶体的自发拉曼光谱，建立了“自由”[WO4]（2-）和[MoO4]（2-）四面体的振动能级图。研究了Me2+阳离子的质量和电负性对内振模位置和线宽的影响。结果表明，板层系中振动级图的变化会改变失相和分裂弛豫机制的发生概率。结果，[WO4]和[MoO4]四面体配合物的完全对称拉曼振动随之在拉曼光谱中被记录在一系列从钙转移到锶和钡的层状晶体中。由于钨酸钡和钼酸钡晶体具有最窄的线宽(δ nu （R) = 1.6 cm(-1)）和最高的拉曼线峰截面，因此它们被认为是最有效的拉曼激光发展的板层晶体。(C) 2000 Elsevier Science B.V.版权所有
Spontaneous Raman spectra of tungstate (MeWO4) and molybdate (MeMoO4) crystals with sheelite structure were investigated (Me = Ca, Sr, Ba, Pb). The energy shift and line broadening of internal vibrational modes were measured in the temperature range from 77 K to the melting point by means of a high temperature Raman spectroscopic technique. The phase transition from sheelite to cubic structure was discovered at a temperature of 1600 K in a BaMo04 crystal. Vibrational level diagrams for "free" [WO4](2-) and [MoO4](2-) tetrahedrons were built on the basis of spontaneous Raman spectra of tungstate and molybdate crystals in the molten state. The effect of mass and electronegativity of Me2+ cations on the position and linewidth of internal vibrational modes was investigated. It was shown that the variation of vibration level diagrams in sheelite series could change the probability of the dephasing and splitting relaxation mechanisms. As a result, the consequent line narrowing of totally symmetric Raman vibrations of [WO4] and [MoO4] tetrahedron complexes was registered in the Raman spectra in a series of sheelite crystals moving from calcium to strontium and barium. Due to the narrowest linewidth (Delta nu (R) = 1.6 cm(-1)) and the highest peak cross-section of the Raman line in barium tungstate and molybdate crystals, they were proposed as the most efficient sheelite crystals for Raman laser development. (C) 2000 Elsevier Science B.V. All rights reserved.