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A: Fachverband Atomphysik

A 5: Atomic Systems in External Fields I

A 5.5: Talk

Monday, March 2, 2009, 17:45–18:00, VMP 6 HS-B

Resonant Dynamics in Time-Dependent Density Functional Theory ? — •Michael Ruggenthaler and Dieter Bauer — Max-Planck-Institut für Kernphysik, Heidelberg

Density functional theory (DFT) [1] and the corresponding time dependent theory (TDDFT) [2] are rigorous reformulations of the quantum many-body problem. The associated nonlinear Kohn-Sham (KS) equations give, in principle, the exact probability density. The crucial point is the approximation of the local exchange-correlation potential describing the internal forces. Resonant dynamics are usually not treated within TDDFT as sufficiently accurate approximations for the exchange-correlation potential do not yet exist. It is assumed that adiabatic approximations derived from groundstate DFT will not be able to reproduce resonant behavior. We investigate Rabi oscillations and show that even simple adiabatic approximations reproduce the dipole of the interacting problem quite well although the charge transfer between the two states involved is not properly described. Moreover we explain why the two-level approximation applied to the noninteracting system leads to unphysical results.

[1] R. M. Dreizler and E. K. U Gross, Density Functional Theory (Springer, Heidelberg, 1990)

[2] M. A. L. Marques et al, Time Dependent Density Functional Theory, Lect. Notes Phys. 706 (Springer, Heidelberg, 2006)