白云鄂博变生褐钇铌矿的Raman光谱和光致发光谱

RAMAN SPECTRA AND VISIBLE PHOTOLUMINESCENCE OF THE METAMICT FERGUSONITE GROUP MINERALS IN BAIYUNOBO

测定了白云鄂博变生及退火结晶的褐钇铌矿和褐铈铌矿的Ｒａｍａｎ光谱，并讨论了结构、成分对Ｒａｍａｎ光谱的影响．它们的Ｒａｍａｎ光谱出现在８４０—６００，３４０—２８０及２００—５０ｃｍ－１的三个区，前两者为ＮｂＯ３－４四面体的伸缩振动和弯曲振动频率，后者为稀土离子和ＮｂＯ３－４四面体的外振动模式，通过对褐钇铌矿族矿物Ｒａｍａｎ光谱的比较分析，表明Ｒａｍａｎ光谱可以有效地反映出该类矿物的结构畸变．还发现退火结晶样品在５１４５或４８８０ｎｍ激光线激发下具有强烈的光致发光现象，而天然变生样品基本上不发光或发光很弱．

Abstract Raman spectra of the metamict and annealing recrystallization fergusonite and brocenite, found in Baiyunobo mineral deposit in China, have been measured and discussed. The spectra give three well defined characteristic band regions. The bands in the regions 840 to 600cm -1 and 340 to 280cm -1 are assigned to NbO 3- 4 tetrahedron stretching and bending vibrations, respectively. While the frequencies observed below 200cm -1 are due to the external modes of the NbO 3- 4 and lanthanide ions. The dependence of Raman frequencies on the structure and composition of the metamict and annealing recrystallization fergusonite group minerals shows that the Raman spectra are valuable for reflecting the structure distortion of the minerals. Additionally, the strong visible photoluminescence from annealing recrystallization is observed when 514.5 or 488.0nm laser line is used as excitation source, whereas metamic fergusonite group minerals exhibit no visible photoluminescence, or weak one.