Kesharwani Manoj K, Manna Debashree, Sylvetsky Nitai, Martin Jan M L
Department of Organic Chemistry, Weizmann Institute of Science , 76100 Reḥovot, Israel.
J Phys Chem A. 2018 Mar 1;122(8):2184-2197. doi: 10.1021/acs.jpca.7b10958. Epub 2018 Feb 15.
We have re-evaluated the X40×10 benchmark for halogen bonding using conventional and explicitly correlated coupled cluster methods. For the aromatic dimers at small separation, improved CCSD(T)-MP2 "high-level corrections" (HLCs) cause substantial reductions in the dissociation energy. For the bromine and iodine species, (n-1)d subvalence correlation increases dissociation energies and turns out to be more important for noncovalent interactions than is generally realized; (n-1)sp subvalence correlation is much less important. The (n-1)d subvalence term is dominated by core-valence correlation; with the smaller cc-pVDZ-F12-PP and cc-pVTZ-F12-PP basis sets, basis set convergence for the core-core contribution becomes sufficiently erratic that it may compromise results overall. The two factors conspire to generate discrepancies of up to 0.9 kcal/mol (0.16 kcal/mol RMS) between the original X40×10 data and the present revision.
我们使用传统和显式相关耦合簇方法重新评估了卤键的X40×10基准。对于小间距的芳香二聚体，改进的CCSD(T)-MP2“高级校正”（HLCs）导致解离能大幅降低。对于溴和碘物种，(n - 1)d次价层相关增加了解离能，并且对于非共价相互作用而言，其重要性比通常所认识到的更高；(n - 1)sp次价层相关的重要性则小得多。(n - 1)d次价层项主要由芯价层相关主导；使用较小的cc-pVDZ-F12-PP和cc-pVTZ-F12-PP基组时，芯-芯贡献的基组收敛变得足够不稳定，以至于可能会整体影响结果。这两个因素共同作用，使得原始X40×10数据与当前修订数据之间产生了高达0.9千卡/摩尔（均方根为0.16千卡/摩尔）的差异。
