Correlating geminal 2JSi-O-Si couplings to structure in framework silicates.
Correlating geminal 2JSi-O-Si couplings to structure in framework silicates.
复制标题
将孪晶 2JSi-O-Si 耦合与骨架硅酸盐的结构相关联。
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
P. Grandinetti
中科院分区：
文献类型：
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作者：
D. J. Srivastava;Pierre Florian;J. Baltisberger;P. Grandinetti
利用第一性原理密度泛函方法研究了29 Si孪晶J耦合对四面体间键结局部结构的影响。对2 JSi-O-Si的影响主要有两个方面：一是与29 Si核的键长有关，二是与29 Si核的平均键长有关。提出了一个描述这些依赖关系的解析表达式，并用于发展一种方法，将2 JSi-O-Si耦合和平均29 Si各向同性化学位移的相关对与两个耦合的29 Si核的键合Si-O-Si角和平均Si-O-Si角联系起来。使用来自硅质沸石Sigma-2的29 Si NMR结果给出该分析的实例。
The dependence of a 29Si geminal J coupling across the inter-tetrahedral linkage on local structure was examined using first-principles DFT calculations. The two main influences on 2JSi-O-Si were found to be a primary dependence on the linkage Si-O-Si angle and a secondary dependence on mean Si-O-Si linkage of the two coupled 29Si nuclei. An analytical expression describing these dependences was proposed and used to develop an approach for relating the correlated pair of 2JSi-O-Si coupling and mean 29Si isotropic chemical shift to the linkage Si-O-Si angle and the mean Si-O-Si angle of the two coupled 29Si nuclei. An example of this analysis is given using 29Si NMR results from the siliceous zeolite Sigma-2.