Exploring Systematic Discrepancies in DFT Calculations of Chlorine Nuclear Quadrupole Couplings.
Exploring Systematic Discrepancies in DFT Calculations of Chlorine Nuclear Quadrupole Couplings.
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DOI：
10.1021/acs.jpca.7b02810
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发表时间：
2017-05
期刊：
影响因子：
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通讯作者：
O. Socha;P. Hodgkinson;C. Widdifield;J. Yates;M. Dračínský
中科院分区：
文献类型：
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作者：
O. Socha;P. Hodgkinson;C. Widdifield;J. Yates;M. Dračínský
以前的研究已经揭示了显着的差异之间的密度泛函理论（DFT）计算和实验的核四极耦合常数（CQ）的氯原子，特别是在离子固体。这里系统地研究了计算的各个方面，包括DFT泛函的选择，基集收敛和几何优化协议。快（fs）的时间尺度动力学的影响进行了探讨，使用分子动力学（MD）和核量子效应（NQE）被认为是使用路径积分MD计算。结果表明，功能的选择是最重要的因素，有关提高四极耦合计算的准确性，并超出广义梯度近似（GGA）的水平，如混合和元GGA泛函的泛函，需要良好的相关性与实验。分子动力学和NQE的影响是不太重要的功能选择在所研究的系统。这里提出了一种方法，其中涉及缩放计算的四极耦合常数，其应用导致与实验数据吻合良好。
Previous studies have revealed significant discrepancies between density functional theory (DFT)-calculated and experimental nuclear quadrupolar coupling constants (CQ) for chlorine atoms, particularly in ionic solids. Various aspects of the computations are systematically investigated here, including the choice of the DFT functional, basis set convergence, and geometry optimization protocol. The effects of fast (fs) time-scale dynamics are probed using molecular dynamics (MD) and nuclear quantum effects (NQEs) are considered using path-integral MD calculations. It is shown that the functional choice is the most important factor related to improving the accuracy of the quadrupolar coupling calculations, and that functionals beyond the generalized gradient approximation (GGA) level, such as hybrid and meta-GGA functionals, are required for good correlations with experiment. The influence of molecular dynamics and NQEs is less important than the functional choice in the studied systems. A method which involves scaling the calculated quadrupolar coupling constant is proposed here; its application leads to good agreement with experimental data.