Pure Nuclear Quadrupole Resonance Studies of Glass Structure

核四极共振(NQR)光谱的进展表明，人们可能能够确定硼酸盐玻璃是否包含结构基团(硼氧基、二硼酸盐、偏硼酸盐等)。它们存在于硼酸盐体系的晶体化合物中。一种新的再生NQR光谱仪在1 MHz下产生约100个硼信号，并允许测量到200 kHz。新的NQR结果使四极耦合和不对称参数的测定优于1%，比核磁共振谱高一个数量级以上。NQR光谱在晶体和玻璃中获得了这些参数的高度精确值，这应该可以肯定地识别硼酸盐二元玻璃中的结构群。还计划对三元玻璃系统进行扩展。还计划将这项工作扩展到铝核，以准确确定铝位置的电场梯度张量，以确定铝的对称性、配位和化学键。

Advances in nuclear quadrupole resonance (NQR) spectroscopy have suggested the possibility one may be able to determine whether borate glasses contain the structural groupings (boroxyl, diborate, metaborate, etc.) that are found in the crystalline compounds of the borate systems. A new regenerative NQR spectrometer yields boron signals of about 100 at 1 MHz and permits measurements down to 200 kHz. The new NQR results allow the quadrupole coupling and asymmetry parameters to be determined to better than 1%, more than an order of magnitude better than from NMR spectra. NQR spectroscopy is yielding highly accurate values of these parameters in crystals and glasses, which should permit a positive identification of the structural groupings in borate binary glasses. Extensions to terniary glass systems are also planned. There are also plans to extend the work to aluminum nuclei to accurately determine the electric field gradient tensors at the aluminum site to ascertain the symmetry, coordination, and chemical bonding of the aluminum.