钨酸盐和钼酸盐功能晶体熔体结构及其晶体生长机制的高温原位拉曼光谱研究

Coupled confocal microscopic resolution and pulsed laser time-resolved techniques were used to measure the temperature dependent Raman spectra of binary and ternary tungstates and molybdates functional crystals and their melts by in situ high temperature Raman spectroscopy. Content dependent Raman spectra were also recorded and the deviations of the spectra were observed. Simultaneously, the micro-structure and the spectra of the crystals and their melts were carried out by using the quantum chemical density functional theory. Thus the experimental spectral vibrational peaks were confirmed by comparison with the result of calculation. The oxygen coordination numbers of tungsten, molybdenum and other componential elements with +3 as valence state and their temperature dependent deviations can be found. And the evolution of the anionic groups structure and the clusters structure in the melt are tracked. The various species and their distributions can be explored and the correlation with the crystal structure can be examined. The componential elements, such as aluminum, bismuth, yttrium and rare earth elements in melts and their quenched states, were measured by means of high temperature X-ray diffraction (scattering), high temperature nuclear magnetic resonance spectroscopy and other measurement methods to assist in the analysis of existing forms and oxygen coordination of such elements. In addition, by designing the crystal growth device which is adequate for in situ observation by high temperature Raman spectroscopy, the space resolved spectra of the crystal growth boundary layer were measured in real time through the selection of the functional crystals which is grown by the same component melting method. Thus, the micro-structure and the clusters evolution law in the boundary layer were studied. The microscopic mechanism of crystal growth could be revealed and interpreted.

耦合共焦显微空间分辨和脉冲激光时间分辨测量技术，采用高温原位拉曼光谱对二元和三元钨酸盐和钼酸盐功能晶体进行升温和熔体的实验测定，且测量组份含量不同的晶体，观察光谱的变化；同时，运用量子化学密度泛函理论对相关晶体及其熔体实施结构模拟和光谱计算，通过与计算的比较验证，厘清实验光谱振动谱峰的归属、钨钼和其它化合价态为+3元素的氧配位数随温度的变化、追踪阴离子基团结构的演变及其在熔体中的团簇基元结构形态，获取钨钼酸盐熔体团簇基元的种类、分布及其与晶体结构的相关性。结合高低温核磁共振谱等其它实测方法对含铝、铋、钇及稀土元素等的钨钼酸盐熔体或其淬冷态进行光谱测量，辅助剖析这类元素结构形态和氧配位状况。此外，通过设计构造用于高温拉曼光谱的原位观测晶体生长装置，选择同成分熔融法生长的功能晶体，实时观察和测量晶体生长边界层的光谱，研究边界层内生长基元的演变规律，揭示和诠释熔融法功能晶体生长的微观生长机制。

通过耦合共焦显微空间分辨、纳秒和皮秒脉冲激光时间分辨测量技术以及卤素灯加热源和激光加热气悬浮试样技术，实现了精细控温、提升检测温度和远距检测，从而丰富和扩大了晶体生长应用的范围和能力。实验观测了二元和三元钨酸盐和钼酸盐功能晶体以及含稀土元素的复合功能晶体的温致和熔体的拉曼光谱，并测量随组份变化的晶体的光谱变化规律和阳离子价态、种类在熔体结构中扮演的角色；同时，运用量子化学密度泛函理论对相关晶体及其熔体实施结构模拟和光谱计算，通过与计算的比较验证，分辨和诊断了实验拉曼光谱振动谱峰的归属、钨钼和其它化合价态为+3元素的氧配位数随温度的变化、追踪阴离子基团结构的演变及其在熔体中的团簇基元结构形态，获取钨钼酸盐熔体团簇基元的种类、分布及其与晶体结构的相关性。由此建立的熔体结构基元的定量分析方法可用于熔体宏观性质如粘度及其随成分变化的相关性研究和诠释。结合核磁共振谱等其它实测方法对含铝、铋、钇及稀土元素等的钨钼酸盐熔体或其淬冷态进行光谱测量，辅助剖析这类元素结构形态和氧配位状况。此外，设计构造了用于高温拉曼光谱的原位观测晶体生长装置，选择同成分熔融法生长的功能晶体，实时观察和测量晶体生长边界层的光谱和结构变化规律。该项目的成功实施，不仅在实验技术上为更高温度晶体生长制备提供了原位实验观测的手段，同时也为熔体和边界层结构及其变化提供了坚实的理论分析途径。