Van der Waals density functional: Self-consistent potential and the nature of the van der Waals bond
Van der Waals density functional: Self-consistent potential and the nature of the van der Waals bond
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DOI：
10.1103/physrevb.76.125112
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发表时间：
2007-09-01
影响因子：
3.7
通讯作者：
Langreth, David C.
中科院分区：
文献类型：
--
作者：
Thonhauser, T.;Cooper, Valentino R.;Langreth, David C.
我们得到了对应于非定域范德华密度泛函的交换关联势[M.Dion，H.Rydberg，E.Schroder，D.C.Langreth和B.I.Lundqvist，Phys.莱特牧师。92、246401(2004年)]。我们用这个势自洽地计算了一些范德华络合物和结晶硅的基态性质。对于后者，在很少或没有范德华相互作用的情况下，我们发现结果主要是由标准广义梯度近似(GGA)中的半局部交换和关联决定的，完全非局部项几乎没有影响。另一方面，我们对van der Waals络合物的计算结果表明，自洽对原子在平衡距离处的相互作用能和结构几乎没有影响。这一发现验证了以前使用相同泛函的计算，该泛函将完全非定域项视为后GGA微扰。将我们的结果与波函数计算进行了比较，证明了我们方法的有效性。交换关联势还允许我们计算Hellmann-Feynman力，从而为有效的几何驰豫提供了手段，并释放了依赖于自洽电荷分布的其他标准技术的潜在用途。从自洽成键电荷的角度讨论了范德华键的性质。
We derive the exchange-correlation potential corresponding to the nonlocal van der Waals density functional [M. Dion, H. Rydberg, E. Schroder, D. C. Langreth, and B. I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004)]. We use this potential for a self-consistent calculation of the ground state properties of a number of van der Waals complexes as well as crystalline silicon. For the latter, where little or no van der Waals interaction is expected, we find that the results are mostly determined by semilocal exchange and correlation as in standard generalized gradient approximations (GGA), with the fully nonlocal term giving little effect. On the other hand, our results for the van der Waals complexes show that the self-consistency has little effect on the atomic interaction energy and structure at equilibrium distances. This finding validates previous calculations with the same functional that treated the fully nonlocal term as a post-GGA perturbation. A comparison of our results with wave-function calculations demonstrates the usefulness of our approach. The exchange-correlation potential also allows us to calculate Hellmann-Feynman forces, hence providing the means for efficient geometry relaxations as well as unleashing the potential use of other standard techniques that depend on the self-consistent charge distribution. The nature of the van der Waals bond is discussed in terms of the self-consistent bonding charge.