Department of Chemistry, University of Georgia, 302 East Campus Road, Athens, Georgia 30602, United States.
Center for Computational Quantum Chemistry, University of Georgia, 1004 Cedar Street, Athens, Georgia 30602, United States.
J Phys Chem A. 2023 May 4;127(17):3743-3756. doi: 10.1021/acs.jpca.2c07743. Epub 2023 Apr 25.
Vacuum UV absorption spectroscopy is regularly used to provide unambiguous identification of a target species, insight into the electronic structure of molecules, and quantitative species concentrations. As molecules of interest have become more complex, theoretical spectra have been used in tandem with laboratory spectroscopic analysis or as a replacement when experimental data is unavailable. However, it is difficult to determine which theoretical methodologies can best simulate experiment. This study examined the performance of EOM-CCSD and 10 TD-DFT functionals (B3LYP, BH&HLYP, BMK, CAM-B3LYP, HSE, M06-2X, M11, PBE0, ωB97X-D, and X3LYP) to produce reliable vacuum UV absorption spectra for 19 small oxygenates and hydrocarbons using vertical excitation energies. The simulated spectra were analyzed against experiment using both a qualitative analysis and quantitative metrics, including cosine similarity, relative integral change, mean signed error, and mean absolute error. Based on our ranking system, it was determined that M06-2X was consistently the top performing TD-DFT method with BMK, CAM-B3LYP, and ωB97X-D also producing reliable spectra for these small combustion species.
真空紫外吸收光谱法常用于明确鉴定目标物种、深入了解分子的电子结构以及定量物种浓度。随着研究对象的分子变得更加复杂，理论光谱已被用于与实验室光谱分析相结合，或者在无法获得实验数据时作为替代。然而，确定哪种理论方法最能模拟实验具有一定难度。本研究考察了 EOM-CCSD 和 10 种 TD-DFT 泛函（B3LYP、BH&HLYP、BMK、CAM-B3LYP、HSE、M06-2X、M11、PBE0、ωB97X-D 和 X3LYP）在使用垂直激发能为 19 种小的含氧化合物和烃类产生可靠真空紫外吸收光谱方面的性能。通过定性分析和定量指标（包括余弦相似度、相对积分变化、平均符号误差和平均绝对误差）对模拟光谱与实验进行了对比。根据我们的排名系统，确定 M06-2X 是性能始终最出色的 TD-DFT 方法，而 BMK、CAM-B3LYP 和 ωB97X-D 也为这些小型燃烧物种生成了可靠的光谱。
