Nano-Bio Spectroscopy Group and ETSF Scientific Development Centre, Dpto. Física de Materiales, Universidad del Pais Vasco, Centro de Física de Materiales CSIC-UPV/EHU-MPC and DIPC, Av. Tolosa 72, San Sebastián E-20018, Spain.
J Chem Phys. 2009 Dec 14;131(22):224105. doi: 10.1063/1.3271392.
The dissociation of molecules, even the most simple hydrogen molecule, cannot be described accurately within density functional theory because none of the currently available functionals accounts for strong on-site correlation. This problem led to a discussion of properties that the local Kohn-Sham potential has to satisfy in order to correctly describe strongly correlated systems. We derive an analytic expression for the nontrivial form of the Kohn-Sham potential in between the two fragments for the dissociation of a single bond. We show that the numerical calculations for a one-dimensional two-electron model system indeed approach and reach this limit. It is shown that the functional form of the potential is universal, i.e., independent of the details of the two fragments.
即使是最基本的氢分子，其分子的离解也无法在密度泛函理论中被准确描述，因为目前还没有任何一个可用的泛函可以处理强局域相关。这个问题导致了对局部 Kohn-Sham 势必须满足的性质的讨论，以便正确描述强相关体系。我们推导出了在单键离解的两个片段之间的 Kohn-Sham 势的非平凡形式的解析表达式。我们证明了对于一维双电子模型系统的数值计算确实趋近并达到了这个极限。结果表明，势的函数形式是普遍的，即与两个片段的细节无关。
