E.K.U. Gross
Institut für Theoretische Physik
Freie Universität Berlin
Traditional density functional theory, necessarily and
inevitably, involves the Born-Oppenheimer approximation: One is supposed to calculate the electronic
ground-state density corresponding to the electrostatic potential generated by clamped nuclei. There are, however, many situations where
the coupling between the electronic and the nuclear motion is important. Examples are the generation of even harmonics in strong laser pulses [1],
the branching ratios of chemical reactions, the electron-phonon interaction with superconductivity as its most dramatic
consequence, and the laser-induced dissociation of molecules. The subject of this lecture is to
describe how one can go beyond the Born-Oppenheimer approximation by treating the fully coupled system of electrons and
nuclei in terms of a multi-component density functional theory. Approximate functionals for the electron-nuclear correlation energy
will be constructed, and first results for molecular ground-state properties will be
presented. A time-dependent generalization of the method will be employed to
describe dissociation processes in laser pulses
such as the ionization-induced Coulomb explosion. Finally, some ideas of how to combine time-dependent density functionaltheory with optimal control theory
will be presented.
[1] T. Kreibich, M. Lein, V. Engel, and E.K.U. Gross, Phys. Rev. Lett. 87, 103901 (2001).
[2] T. Kreibich and E.K.U. Gross, Phys. Rev. Lett. 86, 2984 (2001).