臺灣博碩士論文加值系統

過去20年以來，許多的研究者致力於研究低於100波數非晶形材料的低頻拉曼散射，提出許多的模型來解釋此範圍的譜峰的物理意義；在此範圍內有一個玻色子譜峰(boson pak),是非晶形材料特有的性質。此顯示低頻拉曼散射是研究結構無序的方法。本論文使用張量的運算方式推導解釋玻色子譜峰的模型-Martin and Brenig 模型，此模型認為玻色子譜峰的產生乃由非均勻介電張量的擾動造成材料的無序，推導出玻色子譜峰的強度、結構相關長度、退偏振值。運用ZBLAN及GAS玻璃的拉曼散射及布里淵散射強度實驗，比較退偏振值的實驗和理論值，發現Martin and Brenig 模型的退偏振值適用於不易碎玻璃系統。

In the last 20 years most of the discussions concerning the physics of amorphous solids were devoted to understanding of the low-frequency Ra
-man spectra of these modes in the range of energies lower than 100cm1 .
It is shown that the low-frequency Raman spectroscopy is an effective method for investigation of disordered solids . We use tensor calculation to predominance Martin and Brenig model ,which describes the spectrum in the region of the Boson peak , typical of glasses . the boson peak as a result of first-order light scattering in condensed matter is produced by inhomogeneous fluctuations in dielectric tensor .The model pre
-dicts boson peak the amplitude , structure correlation length , and polari
-zation ratio . Low-frequency Raman and Brillouin measurements have been made on ZBLAN and GAS glasses in order to check the prediction of the model regarding the amplitude and integrated intensity of the bo-
son peak . Comparison of the theoretical and experiment values of the polarization ratio for the boson peak shows a predominance of the tran-
sverse-type atomic motions in this model in strong glasses.

摘要
圖索引 i
表索引 ii
第一章 簡介 1
第二章 理論基礎
2-1 拉曼散射 8
2-2 低頻拉曼散射
2-2-1 前言 14
2-2-2 Disorder-induced model
2-2-2.a Martin-Brenig model 17
2-2-2.b Malinovsky model 19
2-2-3 簡諧準局部振動模型 21
第三章 理論推導
3-1 Martin-Brenig model 24
3-2偏振方向垂直散射面有關的散射光的強度 31
3-3偏振方向平行散射面有關的散射光的強度 36
3-4 結構相關長度與退偏振值的推導 40
第四章 結果與討論
4-1 結構相關長度 46
4-2 退偏振值的討論 52
4-3 未來發展 59
第五章 結論 62

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