Application of London-Type Dispersion Corrections in Solid-State Density Functional Theory for Predicting the Temperature-Dependence of Crystal Structures and Terahertz Spectra
Application of London-Type Dispersion Corrections in Solid-State Density Functional Theory for Predicting the Temperature-Dependence of Crystal Structures and Terahertz Spectra
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DOI：
10.1021/cg200211x
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发表时间：
2011-05-01
影响因子：
3.8
通讯作者：
Korter, Timothy M.
中科院分区：
文献类型：
--
作者：
King, Matthew D.;Korter, Timothy M.
固体密度泛函理论(DFT)已被证明是模拟分子晶体低频振动运动的有价值的工具。虽然通常要求使用实验已知的晶体结构作为这些类型计算的初始输入，但有时会发现不容易获得合适的结晶学数据。在这项研究中，用固态密度泛函理论预测了二水氢氢草酸的β晶型的低温晶胞结构，并对弱的长程色散相互作用进行了修正。色散校正参数针对已知的100Kα晶型晶体结构进行了优化，然后用于β晶体结构的全几何优化。利用这种预测的β晶型结构，模拟了观察到的二水代氢草酸晶型混合物的低温太赫兹光谱。
Solid-state density functional theory (DFT) has been shown to be a valuable tool for the simulation of low-frequency vibrational motions in molecular crystals. While it is typically required that an experimentally known crystal structure be used as the initial input for these types of calculations, it is sometimes found that suitable crystallographic data are not easily obtainable. In this study, the low-temperature unit cell structure of the beta polymorph of deuterated oxalic acid dihydrate, for which a structure has only been reported at room temperature, was predicted using solid-state DFT augmented with a modified empirical correction for weak long-range dispersive interactions. The dispersion correction parameters were optimized against the known 100 K crystal structure of the alpha polymorph, and then used for full-geometry optimization of the beta crystal structure. Using this predicted structure for the beta polymorph, the observed cryogenic THz spectrum of a mixture of deuterated oxalic acid dihydrate polymorphs was simulated.