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首页> 外文会议>International Conference of Computational Methods in Sciences and Engineering >A Comparison of Density Functional Theory and Coupled Cluster Methods for the Calculation of Electric Dipole Polarizability Gradients of Methane
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A Comparison of Density Functional Theory and Coupled Cluster Methods for the Calculation of Electric Dipole Polarizability Gradients of Methane

机译：甲烷电偶极极化梯度计算密度函数理论与耦合簇方法的比较

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摘要

We have compared the performance of density functional theory (DFT) using five different exchange-correlation functionals with four coupled cluster theory based wave function methods in the calculation of geometrical derivatives of the polarizability tensor of methane. The polarizability gradients of hydrocarbons are important ingredients in the simulation of their electron energy loss spectra and reliable but cost-effective methods for obtaining the gradients need to be found. In the present work we present results of a systematic investigation on methane as a prototype molecule with special focus on DFT methods. The KT3, B3LYP, CAM-B3LYP, B97-2 and PBE0 DFT exchange-correlation functionals and the highly correlated wave function methods SOPPA(CCSD), CCSD-LR, CCSD and CCSD(T) were employed in combination with a series of eleven basis sets. Comparison of the DFT results with CCSD(T)/daug-cc-pVQZ reference values reveals that none of the investigated DFT approaches reaches the accuracy of correlated wave function based methods and that the best DFT results are obtained with the PBE0 exchange-correlation functional and Sadlej's polarized valence triple zeta basis set. The SOPPA(CCSD) method, on the other hand, produces results in close agreement with the more expensive pure coupled cluster methods.
机译：我们已经使用五种不同的交换相关功能与具有四个耦合的聚类理论的波函数方法进行了比较了密度泛函理论（DFT）的性能，从而在计算甲烷的极化性张量的几何衍生物的计算中。烃的极化性梯度是它们电子能量损失光谱的模拟中的重要成分，并且需要找到用于获得梯度的可靠但经济有效的方法。在本工作中，我们将甲烷的系统调查显示为原型分子，专注于DFT方法。 KT3，B3LYP，CAM-B3LYP，B97-2和PBE0 DFT交换 - 相关功能和高相关的波函数方法SOPPA（CCSD），CCSD-LR，CCSD和CCSD（T）与一系列11相结合使用基础集。使用CCSD（T）/ DAUG-CC-PVQZ参考值的DFT结果的比较显示，所研究的DFT方法都没有基于波函数的方法的准确性，并且通过PBE0交换相关功能获得了最佳DFT结果和Sadlej的极化价三季度基础集。另一方面，SOPPA（CCSD）方法与更昂贵的纯耦合群集方法密切一致地产生结果。

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