Density-functional study of small molecules within the Krieger-Li-Iafrate approximation
Density-functional study of small molecules within the Krieger-Li-Iafrate approximation
We report density-functional studies of several small molecules $({\mathrm{H}}_{2},$ ${\mathrm{N}}_{2},$ CO, ${\mathrm{H}}_{2}\mathrm{O},$ and ${\mathrm{CH}}_{4})$ within the Krieger-Li-Iafrate (KLI) approximation to the exact Kohn-Sham local exchange potential, using a three-dimensional real-space finite-difference pseudopotential method. It is found that the exchange-only KLI approximation leads to markedly improved eigenvalue spectra compared to those …