Götz Andreas W, Autschbach Jochen, Visscher Lucas
San Diego Supercomputer Center, University of California San Diego, 9500 Gilman Dr MC 0505, La Jolla, California 92093-0505, USA.
Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, USA.
J Chem Phys. 2014 Mar 14;140(10):104107. doi: 10.1063/1.4864053.
We present a method for a subsystem-based calculation of indirect nuclear spin-spin coupling tensors within the framework of current-spin-density-functional theory. Our approach is based on the frozen-density embedding scheme within density-functional theory and extends a previously reported subsystem-based approach for the calculation of nuclear magnetic resonance shielding tensors to magnetic fields which couple not only to orbital but also spin degrees of freedom. This leads to a formulation in which the electron density, the induced paramagnetic current, and the induced spin-magnetization density are calculated separately for the individual subsystems. This is particularly useful for the inclusion of environmental effects in the calculation of nuclear spin-spin coupling constants. Neglecting the induced paramagnetic current and spin-magnetization density in the environment due to the magnetic moments of the coupled nuclei leads to a very efficient method in which the computationally expensive response calculation has to be performed only for the subsystem of interest. We show that this approach leads to very good results for the calculation of solvent-induced shifts of nuclear spin-spin coupling constants in hydrogen-bonded systems. Also for systems with stronger interactions, frozen-density embedding performs remarkably well, given the approximate nature of currently available functionals for the non-additive kinetic energy. As an example we show results for methylmercury halides which exhibit an exceptionally large shift of the one-bond coupling constants between (199)Hg and (13)C upon coordination of dimethylsulfoxide solvent molecules.
我们提出了一种基于子系统的方法，用于在电流自旋密度泛函理论框架内计算间接核自旋-自旋耦合张量。我们的方法基于密度泛函理论中的冻结密度嵌入方案，并将先前报道的基于子系统的核磁共振屏蔽张量计算方法扩展到不仅与轨道自由度而且与自旋自由度耦合的磁场。这导致了一种公式化方法，其中电子密度、感应顺磁电流和感应自旋磁化密度分别针对各个子系统进行计算。这对于在核自旋-自旋耦合常数计算中纳入环境效应特别有用。由于耦合核的磁矩而忽略环境中的感应顺磁电流和自旋磁化密度，会产生一种非常有效的方法，其中仅需对感兴趣的子系统进行计算成本高昂的响应计算。我们表明，这种方法对于计算氢键系统中核自旋-自旋耦合常数的溶剂诱导位移能得出非常好的结果。同样对于具有更强相互作用的系统，考虑到当前可用的非加性动能泛函的近似性质，冻结密度嵌入表现得非常出色。作为一个例子，我们展示了甲基汞卤化物的结果，当二甲基亚砜溶剂分子配位时，它们在（199）Hg和（13）C之间的一键耦合常数表现出异常大的位移。
