Next-generation Molecular Theory Unit, Advanced Science Institute, RIKEN 2-1, Wako, Saitama, Japan.
J Comput Chem. 2011 Nov 30;32(15):3269-75. doi: 10.1002/jcc.21912. Epub 2011 Aug 26.
We applied an improved long-range correction scheme including a short-range Gaussian attenuation (LCgau) to the Becke97 (B97) exchange correlation functional. In the optimization of LCgau-B97 functional, the linear parameters are determined by least squares fitting. Optimizing μ parameter (0.2) that controls long-range portion of Hartree-Fock (HF) exchange to excitation energies of large molecules (Chai and Head-Gordon, J Chem Phys 2008, 128, 084106) and additional short-range Gaussian parameters (a = 0.15 and k = 0.9) that controls HF exchange inclusion ranging from short-range to mid-range (0.5-3 Å) to ground state properties achieved high performances of LCgau-B97 simultaneously on both ground state and excited state properties, which is better than other tested semiempirical density functional theory (DFT) functionals, such as ωB97, ωB97X, BMK, and M0x-family. We also found that while a small μ value (∼0.2) in LC-DFT is appropriate to the local excitation and intramolecular charge-transfer excitation energies, a larger μ value (0.42) is desirable in the Rydberg excitation-energy calculations.
我们将一种改进的长程修正方案（包括短程高斯衰减（LCgau））应用于 Becke97（B97）交换相关泛函。在 LCgau-B97 泛函的优化中，线性参数通过最小二乘法拟合确定。优化μ参数（0.2），控制 Hartree-Fock（HF）交换的远程部分对大分子激发能的影响（Chai 和 Head-Gordon，J Chem Phys 2008, 128, 084106），以及控制 HF 交换包含范围从短程到中程（0.5-3 Å）到基态性质的附加短程高斯参数（a = 0.15 和 k = 0.9），LCgau-B97 在基态和激发态性质上同时实现了高性能，优于其他测试的半经验密度泛函理论（DFT）泛函，如 ωB97、ωB97X、BMK 和 M0x 家族。我们还发现，虽然 LC-DFT 中的小μ值（∼0.2）适合于局部激发和分子内电荷转移激发能，但对于 Rydberg 激发能计算，较大的μ值（0.42）是可取的。
