Generalized gradient approximation Perdew

Perdew, J. P., Wang, Y., 1986, Accurate and Simple Density Functional for the Electronic Exchange Energy Generalized Gradient Approximation , Phys. Rev. B, 33, 8800. 

Perdew JP, Burke K, Wang Y, Real space cutoff construction of a generalized gradient approximation derivation of the PW91 functional, submitted to Phys Rev B... 

Unless otherwise stated, all of our calculations used the generalized gradient approximation as defined by the Perdew-Wang 91 functional. In shorthand, we used PW91-GGA calculations. Unless otherwise stated k points were placed in reciprocal space using the Monkhorst-Pack method. Some specific details for the calculations from each section of the chapter are listed below. 

Perdew JP (1991a) Generalized gradient approximations for exchange and correlation - A look backward and forward, Physica B, 172 1-6... 

Perdew JP, Yue W (1986) Accurate and simple density functional for the electronic exchange energy Generalized gradient approximation, Phys Rev B, 33 8800-8802... 

Perdew JP, Burke K, Emzerhof M (1996) Generalized gradient approximation made simple, Phys Rev Lett, 77 3865-3868... 

Tao J, Perdew JP, Staroverov VN, Scuseria GE (2003) Climbing the density functional ladder Nonempirical meta-generalized gradient approximation designed for molecules and solids, Phys Rev Lett, 91 146401... 

Perdew JP, Chevary JA, Vosko SH, Jackson KA, Pederson MR, Singh DJ, Fiolhais C (1992) Atoms molecules, solids, and surfaces applications of the generalized gradient approximation for exchange and correlation, Phys Rev B, 46 6671—6687... 

All calculations were performed using ab initio density functional theory under the generalized gradient approximation (GGA) with the Perdew-Wang... 

The positions of hydrogen in hydrides are sometimes difficult to be determined experimentally. So, in this study, the crystal structures of hydrides are optimized by the total energy minimization using the plane-wave pseudopotentital method. For this purpose, the first-principle calculations based on the DFT are performed with a generalized gradient approximation (GGA) by Perdew et al. [5]. The implementation of DFT employed here combines a plane-wave basis set with the total energy pseudopotential method, as is embodied in the CASTEP code [6]. 

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