Pérez-Jiménez Angel J, Pérez-Jordá José M, Sancho-García Juan C
Departamento de Química-Física, Universidad de Alicante, Alicante E-03080, Spain.
J Chem Phys. 2007 Sep 14;127(10):104102. doi: 10.1063/1.2770713.
We propose a procedure that combines multiconfigurational (MC) wave functions with two-body density correlation functionals by transforming the latter into functionals of the MC natural orbitals and occupation numbers. The method is tested with the spectroscopic constants of a set of 11 diatomics, the diradical-involved automerization barrier of cyclobutadiene, the energy difference between triplet and open-shell singlet states in He and the methylene molecule, and the magnetic coupling constants of several systems, such as NiO, KNiF(3), K(2)NiF(4), La(2)CuO(4), alpha-4-dehydrotoluene, 1,1('),5,5(')-tetramethyl-6,6(')-dioxo-3,3(')-biverdazyl, Cu(2)Cl(6), copper(II) acetate monohidrate and H-He-H. The procedure is applied to the Colle-Salvetti [Theor. Chim. Acta 37, 329 (1975); 53, 55 (1979)], functional and to a size-consistent functional depending on the on-top pair density (F1-5-N(eff)). On average, the best results are provided by the transformed F1-5-N(eff) [J. Chem. Phys. 114, 2022 (2001)] functional.
我们提出了一种程序，该程序通过将双体密度相关泛函转化为多组态（MC）自然轨道和占据数的泛函，从而将多组态（MC）波函数与双体密度相关泛函相结合。该方法通过一组11个双原子分子的光谱常数、环丁二烯中涉及双自由基的自异构化势垒、氦气和亚甲基分子中三重态与开壳单重态之间的能量差以及几个体系的磁耦合常数进行了测试，这些体系包括氧化镍、氟镍酸钾（KNiF₃）、氟镍酸钾（K₂NiF₄）、铜酸镧（La₂CuO₄）、α-4-脱氢甲苯、1,1′,5,5′-四甲基-6,6′-二氧代-3,3′-联氮烯基、[Cu₂Cl₆]⁻²、一水合醋酸铜（II）和H-He-H。该程序应用于科勒-萨尔韦蒂泛函[《理论化学学报》37, 329 (1975); 53, 55 (1979)]以及一个依赖于顶对密度的尺寸一致泛函（F1-5-N(eff)）。平均而言，变换后的F1-5-N(eff)泛函[《化学物理杂志》114, 2022 (2001)]给出了最佳结果。
