Janesko Benjamin G, Proynov Emil, Kong Jing, Scalmani Giovanni, Frisch Michael J
Department of Chemistry, Texas Christian University , Fort Worth, Texas 76129, United States.
Department of Chemistry, Middle Tennessee State University , Murfreesboro, Tennessee 37132, United States.
J Phys Chem Lett. 2017 Sep 7;8(17):4314-4318. doi: 10.1021/acs.jpclett.7b02023. Epub 2017 Aug 29.
Density functional theory (DFT) uses a density functional approximation (DFA) to add electron correlation to mean-field electronic structure calculations. Standard strategies (generalized gradient approximations GGAs, meta-GGAs, hybrids, etc.) for building DFAs, no matter whether based on exact constraints or empirical parametrization, all face a zero-sum game between overdelocalization (fractional charge error, FC) and underestimation of covalent bonding (fractional spin error, FS). This work presents an alternative strategy. Practical "Rung 3.5" ingredients are used to implement insights from hyper-GGA DFAs that reduce both FS and FC errors. Prototypes of this strategy qualitatively improve FS and FC error over 40 years of standard DFAs while maintaining low cost and practical evaluation of properties. Numerical results ranging from transition metal thermochemistry to absorbance peaks and excited-state geometry optimizations highlight this strategy's promise and indicate areas requiring further development.
密度泛函理论（DFT）使用密度泛函近似（DFA）将电子关联添加到平均场电子结构计算中。构建DFA的标准策略（广义梯度近似GGAs、元GGAs、杂化等），无论基于精确约束还是经验参数化，都面临着过度离域（分数电荷误差，FC）和共价键低估（分数自旋误差，FS）之间的零和博弈。这项工作提出了一种替代策略。实用的“3.5级”成分被用于实现超GGA DFA的见解，从而减少FS和FC误差。该策略的原型在40年的标准DFA基础上定性地改善了FS和FC误差，同时保持了低成本和对性质的实际评估。从过渡金属热化学到吸收峰以及激发态几何结构优化的数值结果突出了该策略的前景，并指出了需要进一步发展的领域。
