A simplified time-dependent density functional theory approach for electronic ultraviolet and circular dichroism spectra of very large molecules
A simplified time-dependent density functional theory approach for electronic ultraviolet and circular dichroism spectra of very large molecules
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DOI：
10.1016/j.comptc.2014.02.023
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发表时间：
2014-07-15
影响因子：
2.8
通讯作者：
Grimme, Stefan
中科院分区：
文献类型：
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作者：
Bannwarth, Christoph;Grimme, Stefan
我们提出了一种简化的时间相关密度泛函理论方法 (sTD-DFT)，可以快速计算具有 500-1000 个原子的分子的电子紫外 (UV) 或圆二色性 (CD) 光谱。矩阵元素的处理方式与最近提出的简化 Tamm-Dancoff 方法 (sTDA, S. Grimme, J. Chem. Phys., 138 (2013), 244104) 相同，但不是应用 Tamm-Dancoff 近似，而是解决标准线性响应密度泛函理论问题。与 sTDA 相比，该方法会导致计算时间增加（与相应的 sTDA 相比，通常增加 2-5 倍），这是合理的，因为所得的跃迁偶极矩通常具有更高的质量。如果对光谱强度（例如单光子振荡器和旋转跃迁强度）感兴趣，这一点就变得很重要。对一些采用标准混合泛函的典型系统从 sTD-DFT 和 sTDA 获得的 UV 和 CD 光谱进行比较表明，两者产生非常相似的激发能，但使用前一种方法获得过渡矩的优点。为了展示 sTD-DFT 对远远超出传统 TD-DFT 范围的系统的适用性，我们展示了取代的手性富勒烯在近 1200 个激发态范围内的圆二色光谱。我们建议将此方法作为预测的更可靠的替代方案，尤其是更具挑战性的 CD 光谱。 (C) 2014 Elsevier B.V. 保留所有权利。
We present a simplified time-dependent density functional theory approach (sTD-DFT) that allows fast computation of electronic ultraviolet (UV) or circular dichroism (CD) spectra of molecules with 500-1000 atoms. The matrix elements are treated in the same way as in the recently proposed simplified Tamm-Dancoff approach (sTDA, S. Grimme, J. Chem. Phys., 138 (2013), 244104) but instead of applying the Tamm-Dancoff approximation, the standard linear-response density functional theory problem is solved. Compared to sTDA, the method leads to an increase in computation time (typically a factor of 2-5 compared to the corresponding sTDA) which is justified since the resulting transition dipole moments are in general of higher quality. This becomes important if spectral intensities (e.g. single-photon oscillator and rotatory transition strengths) are of interest. Comparison of UV and CD spectra obtained from sTD-DFT and sTDA for some typical systems employing standard hybrid functionals shows that both yield very similar excitation energies but the advantage of using the former approach for transition moments. In order to show the applicability of sTD-DFT to systems which are far beyond the scope of conventional TD-DFT, we present the CD spectrum of a substituted, chiral fullerene over a range of almost 1200 excited states. We propose this method as a more reliable alternative for the prediction especially of the more challenging CD spectra. (C) 2014 Elsevier B.V. All rights reserved.