摘要
本文测量了xLi_2O·0.15Ta__2O_5·(0.85-x)GeO_2三元系统玻璃的GeK边和TaL边的EXAFS谱。利用计算机进行曲线拟合得出了玻璃中[CeO_4]四面体和[KeO_6]八面体的百分含量,所得结果表明:该三元系统存在着“锗反常”现象。随着Li_2O的加入,玻璃中[GeO_4]部分转变为[GeO_6]。当 Li_2O含量为25mol％时,[GeO_6]含量达到极大值.即[GeO_6]为25％,当继续加入Li_2O时非桥氧的[GeO_4]增加,而下稳定的[GeO_6]减少。钽L边的EXAFS研究表明:钽在玻璃中主要以[GeO_6]八面体存在,T-O键长为1.98A·左右。同时探讨了玻璃的结构模型。
The EXAFS spectra of Gek and TaLI in xLi2O. 0. 15Ta2O5. (0. 85-x) GeO2 ternary system was studied. The percents of GeO4 and GeO6 were gained by means of curve fitting in the computer. The results show that there is'Ge anomaly' in ternary system. The part GeO4 is changed into GeO5 with increasing Li2O in glass. GeO6 contents reach the miximum in the system with 25mol% Li2O. or the percents of Geo6 is equal to 25%. Nonbridge oxygen GeO4 increases and unstready GeO6 decreases with adding Li2O continually. The study in the spectra of TaLI show that the coodination of Ta atom is 6. Ta -O distance is about 1. 98A . At the Same time, the strulctural model of glass is disscussed.
