Institut für Theoretische Chemie, Universität Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart, Germany.
J Chem Phys. 2011 Jan 21;134(3):034113. doi: 10.1063/1.3528720.
An internally contracted multireference configuration interaction is developed which employs wave functions that explicitly depend on the electron-electron distance (MRCI-F12). This MRCI-F12 method has the same applicability as the MRCI method, while having much improved basis-set convergence with little extra computational cost. The F12b approximation is used to arrive at a computationally efficient implementation. The MRCI-F12 method is applied to the singlet-triplet separation of methylene, the dissociation energy of ozone, properties of diatomic molecules, and the reaction barrier and exothermicity of the F + H(2) reaction. These examples demonstrate that already with basis sets of moderate size the method provides near complete basis set MRCI accuracy, and hence quantitative agreement with the experimental data. As a side product, we have also implemented the explicitly correlated multireference averaged coupled pair functional method (MRACPF-F12).
我们开发了一种内在收缩的多参考组态相互作用，它采用了明确依赖于电子-电子距离的波函数（MRCI-F12）。这种 MRCI-F12 方法与 MRCI 方法具有相同的适用性，同时具有更好的基组收敛性，而计算成本增加很少。使用 F12b 近似值实现了计算效率的提高。MRCI-F12 方法应用于亚甲基的单重态-三重态分离、臭氧的离解能、双原子分子的性质以及 F + H(2)反应的反应势垒和放热。这些例子表明，即使使用中等大小的基组，该方法也能提供接近完全基组 MRCI 精度，从而与实验数据定量一致。作为一个副产品，我们还实现了显式相关的多参考平均耦合对泛函方法（MRACPF-F12）。
