Department of Chemistry, University of Copenhagen, Copenhagen Ø, Denmark.
J Comput Chem. 2011 Nov 30;32(15):3168-74. doi: 10.1002/jcc.21897. Epub 2011 Aug 26.
We present a benchmark study of a combined multipole spin-spin coupling constant (SSCC) polarizability/reaction field (MJP/RF) approach to the calculation of both specific and bulk solvation effects on SSCCs of solvated molecules. The MJP/RF scheme is defined by an expansion of the SSCCs of the solvated molecule in terms of coupling constant dipole and quadrupole polarizabilities and hyperpolarizabilities derived from single molecule ab initio calculations. The solvent electric field and electric field gradient are calculated based on data derived from molecular dynamics (MD) simulations thereby accounting for solute-solvent dynamical effects. The MJP/RF method is benchmarked against polarizable QM/MM calculations for the one-bond N-H coupling constant in N-methylacetamide. The best agreement between the MJP/RF and QM/MM approaches is found by truncating the electric field expansion in the MJP/RF approach at the linear electric field level. In addition, we investigate the sensitivity of the results due to the choice of one-electron basis set in the ab initio calculations of the coupling constant (hyper-)polarizabilities and find that they are affected by the basis set in a way similar to the coupling constants themselves.
我们提出了一种基于多极自旋-自旋耦合常数（SSCC）极化率/反应场（MJP/RF）的组合方法的基准研究，用于计算溶剂化分子的 SSCC 的特定和总体溶剂化效应。MJP/RF 方案是通过将溶剂化分子的 SSCC 展开为从单分子从头算计算得出的耦合常数偶极和四极极化率和非线性极化率来定义的。溶剂电场和电场梯度是根据分子动力学（MD）模拟得出的数据计算的，从而考虑了溶质-溶剂动力学效应。MJP/RF 方法与可极化 QM/MM 计算进行了基准测试，用于计算 N-甲基乙酰胺中 N-H 单键耦合常数。通过在 MJP/RF 方法中在线性电场水平截断电场展开，发现 MJP/RF 和 QM/MM 方法之间的最佳一致性。此外，我们研究了由于耦合常数（超）极化率的从头算计算中选择单电子基组而导致的结果敏感性，并发现它们受基组的影响与耦合常数本身相似。
