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M: Metallphysik

M 30: Elektronische Eigenschaften

M 30.2: Fachvortrag

Donnerstag, 29. März 2001, 17:30–17:45, S5.3

Assesment of exchange-correlation kernels for excited states in solids — •Krzysztof Tatarczyk, Arno Schindlmayr, and Matthias Scheffler — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin-Dahlem, Germany

The performance of several common approximations for the exchange-correlation kernel within time-dependent density functional theory is tested for elementary excitations in the homogeneous electron gas. Although the adiabatic local-density approximation gives a resonably good account of the plasmon dispersion, systematic errors are pointed out and tracked to the neglect of the wavevector dependence. Kernels optimized for atoms are found to perform poorly in extended systems due to an incorrect behaviour in the long-wavelength limit, leading to quantitative deviations that significantly exceed the experimental error bars for the plasmon dispersion in the alkali metals.