Identifying pragmatic quasi-harmonic electronic structure approaches for modeling molecular crystal thermal expansion
Identifying pragmatic quasi-harmonic electronic structure approaches for modeling molecular crystal thermal expansion
复制标题
确定用于模拟分子晶体热膨胀的实用准谐波电子结构方法
DOI：
10.1039/c8fd00048d
复制
发表时间：
2018
影响因子：
3.4
通讯作者：
Beran, Gregory J.
中科院分区：
文献类型：
--
作者：
McKinley, Jessica L.;Beran, Gregory J.
准谐波方法为分子晶体结构和性质的温度依赖性建模提供了一种经济的途径。一些研究已经证明了这些模型的良好性能，至少对于刚性分子来说，当使用基于片段的方法和相关波函数技术时。其他许多人利用色散校正密度泛函理论（DFT）取得了成功。在这里，对能量、几何形状和声子用相关方法或DFT计算的模型进行了层次分析，以确定哪些组合可以对摩尔体积、焓和熵等属性（作为温度的函数）产生有用的预测。结果表明，基于色散校正的二阶Møller-Plesset微扰理论，改进DFT几何形状和单点能量声子，与单独使用DFT得到的结果相比，可以明显改善摩尔体积和焓。由振动贡献控制的预测熵，从混合方案中获益不太明显。利用这些混合技术，预测了对乙酰氨基酚（扑热息痛）的室温热化学，以解决两个实验升华焓测量之间的差异。
Quasi-harmonic approaches provide an economical route to modeling the temperature dependence of molecular crystal structures and properties. Several studies have demonstrated good performance of these models, at least for rigid molecules, when using fragment-based approaches with correlated wavefunction techniques. Many others have found success employing dispersion-corrected density functional theory (DFT). Here, a hierarchy of models in which the energies, geometries, and phonons are computed either with correlated methods or DFT are examined to identify which combinations produce useful predictions for properties such as the molar volume, enthalpy, and entropy as a function of temperature. The results demonstrate that refining DFT geometries and phonons with single-point energies based on dispersion-corrected second-order Møller–Plesset perturbation theory can provide clear improvements in the molar volumes and enthalpies compared to those obtained from DFT alone. Predicted entropies, which are governed by vibrational contributions, benefit less clearly from the hybrid schemes. Using these hybrid techniques, the room-temperature thermochemistry of acetaminophen (paracetamol) is predicted to address the discrepancy between two experimental sublimation enthalpy measurements.