Aspherical scattering factors for SHELXL - model, implementation and application
Aspherical scattering factors for SHELXL - model, implementation and application
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DOI：
10.1107/s2053273318013840
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发表时间：
2019-01-01
影响因子：
1.8
通讯作者：
Dittrich, Birger
中科院分区：
文献类型：
--
作者：
Luebben, Jens;Wandtke, Claudia M.;Dittrich, Birger
一种新的非球面散射因子的形式主义已实施在晶体学最小二乘精化程序SHELXL。该形式依赖于高斯函数，并可以选择性地补充独立原子模型，以考虑由于化学键和孤对电子密度分布的变形。非球形贡献来自电子密度获得的量子化学密度泛函理论计算的合适的模型化合物，包含特定的化学环境，定义的不变形式主义。由于一个新的算法，不变量分配的细化SHELXL是自动化的。在新的模型中，每个化学环境的一个合适的参数化是通过元分析实现的。使用新模型后，晶体学最小二乘精修的品质因数、精密度和准确度显著提高。
A new aspherical scattering factor formalism has been implemented in the crystallographic least-squares refinement program SHELXL. The formalism relies on Gaussian functions and can optionally complement the independent atom model to take into account the deformation of electron-density distribution due to chemical bonding and lone pairs. Asphericity contributions were derived from the electron density obtained from quantum-chemical density functional theory computations of suitable model compounds that contain particular chemical environments, as defined by the invariom formalism. Thanks to a new algorithm, invariom assignment for refinement in SHELXL is automated. A suitable parameterization for each chemical environment within the new model was achieved by metaheuristics. Figures of merit, precision and accuracy of crystallographic least-squares refinements improve significantly upon using the new model.