Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA.
J Chem Phys. 2012 Jan 14;136(2):024103. doi: 10.1063/1.3674992.
We propose a wave function-based method for the decomposition of intermolecular interaction energies into chemically-intuitive components, isolating both mean-field- and explicit correlation-level contributions. We begin by solving the locally-projected self-consistent field for molecular interactions equations for a molecular complex, obtaining an intramolecularly polarized reference of self-consistently optimized, absolutely-localized molecular orbitals (ALMOs), determined with the constraint that each fragment MO be composed only of atomic basis functions belonging to its own fragment. As explicit inter-electronic correlation is integral to an accurate description of weak forces underlying intermolecular interaction potentials, namely, coordinated fluctuations in weakly interacting electronic densities, we add dynamical correlation to the ALMO polarized reference at the coupled-cluster singles and doubles level, accounting for explicit dispersion and charge-transfer effects, which map naturally onto the cluster operator. We demonstrate the stability of energy components with basis set extension, follow the hydrogen bond-breaking coordinate in the C(s)-symmetry water dimer, decompose the interaction energies of dispersion-bound rare gas dimers and other van der Waals complexes, and examine charge transfer-dominated donor-acceptor interactions in borane adducts. We compare our results with high-level calculations and experiment when possible.
我们提出了一种基于波函数的方法，用于将分子间相互作用能分解为具有化学直观性的成分，分离出均场和显式相关能级的贡献。我们首先为分子复合物求解局部投影自洽场分子相互作用方程，得到一个分子内极化的参考，其中包含自洽优化的绝对局部分子轨道（ALMO），其约束条件是每个片段 MO 仅由属于其自身片段的原子基函数组成。由于显式电子相关对于准确描述分子间相互作用势中的弱力至关重要，即弱相互电子密度的协调波动，因此我们在耦合簇单双水平上向 ALMO 极化参考添加动态相关，以考虑显式色散和电荷转移效应，这些效应自然映射到簇算子上。我们通过基组扩展来证明能量成分的稳定性，跟踪 C(s)对称水分子二聚体中氢键断裂的坐标，分解色散束缚的稀有气体二聚体和其他范德华复合物的相互作用能，并研究硼烷加合物中电荷转移主导的供体-受体相互作用。我们尽可能地将我们的结果与高精度计算和实验进行比较。
