A Generalized Gradient Approximation with Local Parameters.

The dependence of typical generalized gradient approximations (GGA) for exchange-correlation (XC) on fixed, global parameters makes them incapable of providing good accuracy in predicting, simultaneously, molecular and solid properties. This drawback has motivated recent interest in constructing more flexible GGAs incorporating XC parameters that depend on the density, bounding their values to those for the high- and low-density regimes. In this work we explore a scheme to couple X and C functionals through the density-dependence of the gradient expansion coefficient derived beyond the random phase approximation [1,2] employed in different C functionals [3-5]. We discuss the implications of such local dependence of the gradient coefficient and show results of these GGAs for various properties involving test sets of atoms, molecules, and solids.


1. C. D. Hu, D. C. Langreth, Phys. Rev. B 33, 943 (1986).
2. M. Rasolt, D. J. W. Geldart, Phys. Rev. B 34, 1325 (1986).
3. J. P. Perdew, Phys. Rev. B 33, 8822 (1986).
4. J. P. Perdew, A. Ruzsinszky, G. I. Csonka, L. A. Constantin, J. Sun, Phys. Rev. Lett. 103, 026403 (2009).
5. A. Cancio, G. P. Chen, B. T. Krull, K. Burke, J. Chem. Phys. 149, 084116 (2018).