Theoretical Chemistry, Amsterdam Center for Multiscale Modeling, Vrije Universiteit Amsterdam, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
J Chem Phys. 2010 Jan 28;132(4):044114. doi: 10.1063/1.3297886.
We have assessed the accuracy of a representative set of currently available approximate kinetic-energy functionals used within the frozen-density embedding scheme for the NgAuF (Ng=Ar, Kr, Xe) molecules, which we partitioned into a Ng and a AuF subsystem. Although it is weak, there is a covalent interaction between these subsystems which represents a challenge for this subsystem density functional theory approach. We analyzed the effective-embedding potentials and resulting electron density distributions and provide a quantitative analysis of the latter from dipole moment differences and root-mean-square errors in the density with respect to the supermolecular Kohn-Sham density functional theory reference calculation. Our results lead to the conclusion that none of the tested approximate kinetic-energy functionals performs well enough to describe the bond between the noble gas and gold adequately. This observation contributes to the growing evidence that the current procedure to obtain approximate kinetic-energy functionals by reparametrizing functionals obtained via the "conjointness" hypothesis of Lee, Lee, and Parr [Phys. Rev. A 44, 768 (1991)] is insufficient to treat metal-ligand interactions with covalent character.
我们评估了目前在冻结密度嵌入方案中用于 NgAuF（Ng=Ar、Kr、Xe）分子的一组具有代表性的近似动能泛函的准确性，我们将其分为 Ng 和 AuF 子系统。尽管这种相互作用很弱，但这些子系统之间存在共价相互作用，这对子系统密度泛函理论方法构成了挑战。我们分析了有效嵌入势和由此产生的电子密度分布，并从偶极矩差异和相对于超分子 Kohn-Sham 密度泛函理论参考计算的密度均方根误差对后者进行了定量分析。我们的结果得出结论，没有一个测试的近似动能泛函能够足够好地描述稀有气体和金之间的键。这一观察结果有助于越来越多的证据表明，目前通过重新参数化通过 Lee、Lee 和 Parr [Phys. Rev. A 44, 768（1991）] 的“一致性”假设获得的泛函来获得近似动能泛函的方法不足以处理具有共价性质的金属配体相互作用。
