High field (33)S solid state NMR and first-principles calculations in potassium sulfates.
High field (33)S solid state NMR and first-principles calculations in potassium sulfates.
复制标题
硫酸钾的高场 (33)S 固态核磁共振和第一原理计算。
DOI：
10.1021/jp908206c
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
J. Ripmeester
中科院分区：
文献类型：
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作者：
I. Moudrakovski;S. Lang;S. Patchkovskii;J. Ripmeester
(33)S固体核磁共振研究了一组呈现多种硫环境(K(2)SO(4)，KHSO(4)，K(2)S(2)O(7)，K(2)S(2)O(8))的硫酸盐，在21T下，S的低自然丰度(0.75%)和小的旋磁比即使在如此高的磁场下也是一个严重的挑战。然而，使用QCPMG技术，我们能够从C(Q)值接近16 MHz的站点获得良好的信号。用Gaussian98和CASTEP程序进行量子力学计算，辅助计算了EFG张量的位置和相对取向。用密度泛函方法和规范无关的原子轨道对约100-120个原子的分子团簇进行了Gauss98计算。CASTEP计算使用了周期边界条件和包含规范的投影器增广波赝势方法。虽然在实验参数和计算参数之间只观察到半定量的一致，但计算在解释实验数据方面是非常有用的辅助。
A set of potassium sulfates presenting a variety of sulfur environments (K(2)SO(4), KHSO(4), K(2)S(2)O(7), and K(2)S(2)O(8)) has been studied by (33)S solid state NMR at 21 T. Low natural abundance (0.75%) and small gyromagnetic ratio of (33)S presented a serious challenge even at such a high magnetic field. Nevertheless, using the QCPMG technique we were able to obtain good signals from the sites with C(Q) values approaching 16 MHz. Assignment of the sites and the relative orientations of the EFG tensors were assisted by quantum mechanical calculations using the Gaussian 98 and CASTEP packages. The Gaussian 98 calculations were performed using the density functional method and gauge independent atomic orbitals on molecular clusters of about 100-120 atoms. The CASTEP calculations utilized periodic boundary conditions and a gauge-including projector augmented-wave pseudopotential approach. Although only semiquantitative agreement is observed between the experimental and calculated parameters, the calculations are a very useful aid in the interpretation of experimental data.