Department of Chemistry, University of California, and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-1460, USA.
Phys Chem Chem Phys. 2012 Nov 28;14(44):15328-39. doi: 10.1039/c2cp42522j. Epub 2012 Oct 10.
Using the ωB97X-D and B3LYP density functionals, the absolutely localized molecular orbital energy decomposition method (ALMO-EDA) is applied to the water dimer through pentamer, 13-mer and 17-mer clusters. Two-body, three-body, and total interaction energies are decomposed into their component energy terms: frozen density interaction energy, polarization energy, and charge transfer energy. Charge transfer, polarization, and frozen orbital interaction energies are all found to be significant contributors to the two-body and total interaction energies; the three-body interaction energies are dominated by polarization. Each component energy term for the two-body interactions is highly dependent on the associated hydrogen bond distance. The favorability of the three-body terms associated with the 13- and 17-mer structures depends on the hydrogen-donor or hydrogen-acceptor roles played by each of the three component waters. Only small errors arise from neglect of three-body interactions without two adjacent water molecules, or beyond three-body interactions. Interesting linear correlations are identified between the contributions of charge-transfer and polarization terms to the two and three-body interactions, which permits elimination of explicit calculation of charge transfer to a good approximation.
采用 ωB97X-D 和 B3LYP 密度泛函，通过五聚体、十三聚体和十七聚体簇，将绝对局域分子轨道能量分解方法（ALMO-EDA）应用于水二聚体。将二体、三体和总相互作用能分解为其组成的能量项：冻结密度相互作用能、极化能和电荷转移能。电荷转移、极化和冻结轨道相互作用能都被发现对二体和总相互作用能有显著贡献；三体相互作用能主要由极化决定。对于二体相互作用的每个组成能量项，都高度依赖于相关氢键距离。与 13 聚体和 17 聚体结构相关的三体项的有利性取决于三个组成水分子中每个分子的供氢或受氢作用。如果忽略没有两个相邻水分子的三体相互作用或超出三体相互作用，则会产生很小的误差。在二体和三体相互作用中，电荷转移和极化项的贡献之间存在有趣的线性相关性，这允许在很好的近似下消除对电荷转移的显式计算。
