The semilocal meta generalized gradient approximation (MGGA) for the exchange-correlation functional of Kohn-Sham (KS) density functional theory can yield accurate ground-state energies simultaneously for atoms, molecules, surfaces, and solids, due to the inclusion of kinetic energy density as an input. We study for the first time the effect and importance of the dependence of MGGA on the kinetic energy density through the dimensionless inhomogeneity parameter, $\alpha$, that characterizes the extent of orbital overlap. This leads to a simple and wholly new MGGA exchange functional, which interpolates between the single-orbital regime, where $\alpha=0$, and the slowly varying density regime, where $\alpha \approx 1$, and then extrapolates to $\alpha \to \infty$. When combined with a variant of the Perdew-Burke-Erzerhof (PBE) GGA correlation, the resulting MGGA performs equally well for atoms, molecules, surfaces, and solids.
翻译:Kohn-Sham (KS) 密度功能理论的交换-关系功能半局部通用梯度近似值(MGGA) 可以同时产生精确的地面状态能量, 原子、 分子、 表面和固体, 这是因为将动能密度作为一种输入。 我们第一次研究MGGA依赖运动能量密度的影响和重要性, 其方式为无尺寸不相容参数 $\ alpha$, 这是轨道重叠程度的特点。 这导致一个简单和全新的MGGA 交换功能, 它在单轨道系统( $\ alpha=0) 和缓慢变化的密度系统( $\ alpha\ approx 1 $) 之间, 以及缓慢变化的密度系统( $\ alpha = approx 1) 之间, 然后将外推至 $\alpha \ \ to inty$。 当与 Perdew- Burke- ERhhoferhof (PEGGA) GGA 相关变体时, 结果MGGGGGGGGGGGGGGGA 表现同样好。