轨道优化与时间依赖密度 内部分子电荷转移的功能计算 激发状态
Elli Selenius1, Alec Elías Sigurdarson1, Yorick L A Schmerwitz1
1Science Institute of the University of Iceland, Reykjavík 107, Iceland.
Journal of chemical theory and computation
|May 2, 2024
概括
轨道优化计算准确量化有机分子中的电荷转移,在长距离激发方面表现优于时间依赖密度函数理论 (TD-DFT). 这种方法为激发状态计算提供了更高的准确性.
科学领域:
- 计算化学是一种计算化学.
- 量子化学是一种量子化学.
- 理论物理学的理论物理.
背景情况:
- 精确计算激发状态,特别是那些涉及电荷转移的状态,对于理解有机分子特性至关重要.
- 线性响应时间依赖密度函数理论 (TD-DFT) 是一种常见的方法,但可以与远程电荷转移激发作斗争.
研究的目的:
- 评估时间独立,轨道优化的兴奋状态计算的性能.
- 为了将这种方法与TD-DFT进行比较,用于有机分子中的电荷转移激发.
- 在轨道优化框架内评估不同密度函数 (LDA,GGA,混合) 的准确性.
主要方法:
- 采用直接优化方法在电子能量表面上找到位.
- 使用局部密度近似 (LDA) 和通用梯度近似 (GGA) 函数 (PBE,BLYP) 进行计算.
- 用TD-DFT比较结果,包括使用轨道放松的Z向量方法进行计算.
主要成果:
- 轨道优化的计算提供了放松的兴奋状态电子密度,使电荷转移能够准确量化.
- 与轨道优化的方法相比,TD-DFT通常高估了电荷传输距离.
- 使用LDA/GGA函数的轨道优化计算实现了~0.7 eV的平均绝对误差,在远距离电荷传输方面超过了TD-DFT.
- 混合功能 (B3LYP,CAM-B3LYP) 提高了激发能精度,CAM-B3LYP 的误差为0.15 eV.
结论:
- 时间独立的,轨道优化的计算是研究有机分子中电荷转移激发的强大而准确的方法.
- 这种方法超过了TD-DFT,特别是在涉及显著电荷分离的激发方面.
- 将精确交换纳入混合函数中,主要提高了激发能量的精度,而不是电荷传输距离.
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