In summary, we have presented a model for the longitudinal and transverse xc potentials of the homogeneous electron gas. Our results have been fitted7 to analytic expressions to facilitate their use as input for DFT calculations in the linearized long-wavelength regime. Similar calculations of the xc potentials in a two-dimensional electron gas with e 2 /r interactions show spectral structure and non-monotonic behavior in Re f xc even though in 2D the plasma frequency vanishes at long wavelengths [12]. Earlier calculations were done by Holas and Singwi [13]. Available data on the plasmon dispersion coefficient in alkali metals3 indicate strong deviations from RPA with increasing coupling strength. Although band-structure effects play a significant role in a quantitative comparison, the dynamic correction indicated by our results for Re f xc improves the agreement with the experimental data. The spectral structure at 2? may possibly be observable in electron-energy-loss experiments on a metal such as Rb, in which the plasmon dispersion curve is almost flat.
Exchange-Correlation Potentials in the Electron Gas
2002
Abstract
In summary, we have presented a model for the longitudinal and transverse xc potentials of the homogeneous electron gas. Our results have been fitted7 to analytic expressions to facilitate their use as input for DFT calculations in the linearized long-wavelength regime. Similar calculations of the xc potentials in a two-dimensional electron gas with e 2 /r interactions show spectral structure and non-monotonic behavior in Re f xc even though in 2D the plasma frequency vanishes at long wavelengths [12]. Earlier calculations were done by Holas and Singwi [13]. Available data on the plasmon dispersion coefficient in alkali metals3 indicate strong deviations from RPA with increasing coupling strength. Although band-structure effects play a significant role in a quantitative comparison, the dynamic correction indicated by our results for Re f xc improves the agreement with the experimental data. The spectral structure at 2? may possibly be observable in electron-energy-loss experiments on a metal such as Rb, in which the plasmon dispersion curve is almost flat.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
