Exchange Potential: LDA and GGA versus Exact Potential

I) Brief introduction

The exact multiplicative exchange potential of density functional theory can be obtained numerically via the optimized potential method (OPM) [1]. The OPM results can be used to analyze the properties of approximate density functionals for the exchange energy, as the local density approximation (LDA) and the generalized gradient approximation (GGA). Below these approximations are compared with the exact potentials for a number of systems, ranging from atoms to solids. Sometimes also the Krieger-Li-Iafrate (KLI) approximation [2] to the exact exchange potential is displayed.
The units of the plots are as follows: All length scales are given in Bohr, the potentials are in Hartree. 


To read more clik on the link below :


http://th.physik.uni-frankfurt.de/~engel/vx-nr.html#top