Benchmarking DFT approaches for the calculation of polarizability inputs for refractive index predictions in organic polymers
Benchmarking DFT approaches for the calculation of polarizability inputs for refractive index predictions in organic polymers
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DOI：
10.1039/c8cp05492d
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发表时间：
2019-02-28
影响因子：
3.3
通讯作者：
Hachmann, Johannes
中科院分区：
文献类型：
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作者：
Afzal, Mohammad Atif Faiz;Hachmann, Johannes
在以前的研究中，我们引入了一种新的计算协议，使用第一性原理和数据建模的组合来准确预测有机聚合物的折射率（RI）。该协议是基于Lorentz-Lorenz方程，并涉及计算的静态极化率和低聚物序列的数密度，这是外推到聚合物的限制。我们选择使用PBE 0/def 2-TZVP-D3模型化学在密度泛函理论（DFT）框架内计算极化率。虽然这种特别的选择被证明是非常成功的，但从计算的角度来看，它也相对昂贵。它代表了整个RI建模协议中的瓶颈步骤，从而限制了其在虚拟高通量筛选研究中的实用性，其中效率至关重要。对于表现出迟发型延伸性的聚合物，所采用的线性外推方案可能需要对长寡聚物序列进行苛刻的计算，从而成为另一个瓶颈。在这里介绍的工作中，我们对DFT模型化学进行基准测试，以确定优化该应用领域准确性和效率之间平衡的方法。我们比较共轭和非共轭聚合物的结果，增加我们原来的外推方法与非线性选项，分析极化率误差如何传播到RI预测，并提供指导方法选择。
In a previous study, we introduced a new computational protocol to accurately predict the index of refraction (RI) of organic polymers using a combination of first-principles and data modeling. This protocol is based on the Lorentz-Lorenz equation and involves the calculation of static polarizabilities and number densities of oligomer sequences, which are extrapolated to the polymer limit. We chose to compute the polarizabilities within the density functional theory (DFT) framework using the PBE0/def2-TZVP-D3 model chemistry. While this ad hoc choice proved remarkably successful, it is also relatively expensive from a computational perspective. It represents the bottleneck step in the overall RI modeling protocol, thus limiting its utility for virtual high-throughput screening studies, in which efficiency is essential. For polymers that exhibit late-onset extensivity, the employed linear extrapolation scheme can require demanding calculations on long-oligomer sequences, thus becoming another bottleneck. In the work presented here, we benchmark DFT model chemistries to identify approaches that optimize the balance between accuracy and efficiency for this application domain. We compare results for conjugated and non-conjugated polymers, augment our original extrapolation approach with a non-linear option, analyze how the polarizability errors propagate into the RI predictions, and offer guidance for method selection.