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首页> 外文期刊>Acta Crystallographica, Section B. Structural science, crystal engineering and materials >Azulene revisited: solid-state structure, invariom modeling and lattice-energy minimization of a classical example of disorder
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Azulene revisited: solid-state structure, invariom modeling and lattice-energy minimization of a classical example of disorder

机译：亚祖琳重新判断：固态结构，无限造型和晶格 - 能量最小化疾病的典型例子

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摘要

The molecular and solid-state structure of azulene both raise fundamental questions. Therefore, the disordered crystal structure of azulene was re-refined with invariom non-spherical atomic scattering factors from new single-crystal X-ray diffraction data with a resolution of d = 0.45 ?. An unconstrained refinement results in a molecular geometry with C_s symmetry. Refinements constrained to fulfill C_(2v) symmetry, as observed in the gas phase and in highlevel ab initio calculations, lead to similar figures of merit and residual densities as unconstrained ones. Such models are consistent with the structures from microwave spectroscopy and electron diffraction, albeit they are not the same. It is shown that for the disorder present in azulene, the invariom model describes valence electron density as successfully as it does for non-disordered structures, although the disorder still leads to high correlations mainly between positional parameters. Lattice-energy minimizations on a variety of ordered model structures using dispersion-corrected DFT calculations reveal that the local deviations from the average structure are small. Despite the molecular dipole moment there is no significant molecular ordering in any spatial direction. A superposition of all ordered model structures leads to a calculated average structure, which explains not only the experimental determined atomic coordinates, but also the apparently unusual experimental anisotropic displacement parameters.
机译：紫苏的分子和固态结构既促进了基本问题。因此，用来自新的单晶X射线衍射数据的Inviriom非球面原子散射因子重新精制茉莉烯的无序晶体结构，其分辨率为d = 0.45？。无约束的细化导致具有C_S对称性的分子几何形状。限制以满足C_（2V）对称性的细化，如在气相中观察到的，导致与未经约束的相似的优点和残留密度的图形。这些模型与微波谱和电子衍射的结构一致，尽管它们不一样。结果表明，对于紫红素中存在的病症，因此虽然这种疾病仍然导致位置参数之间的紊乱仍然导致高相关性，但是作为非无序结构，因此无序模型描述了价值。使用色散校正的DFT计算的各种有序模型结构的格子 - 能量最小化表明，与平均结构的局部偏差很小。尽管分子偶极力矩，但在任何空间方向上都没有显着的分子序排序。所有有序模型结构的叠加导致计算的平均结构，这不仅解释了实验确定的原子坐标，而且解释了明显异常的实验各向异性位移参数。

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