Colloquium on June 13th, 2005

Eberhard K. U. Gross
Freie Universität Berlin

Time-dependent density functional theory: Basic concepts and new developments

For large many-particle systems, the wave function is an illegitimate scientific concept [Walter Kohn, Nobel Lecture], illegitimate in the sense that it can neither be calculated nor stored. Modern density functional theory is based on the suprising fact that knowledge of the ground-state density alone is sufficient to calculate all physical observables of a stationary quantum system. In this lecture, a time-dependent generalization of density functional theory (TDDFT) will be presented. After an overview of the basic concepts, several new developments will be described. Those include: (i) A generalizaion of TDDFT which treats both electrons and nuclei quantum mechanically. (ii) A time-dependent generalization of the so-called electron localization function which allows the time-resolved visualization of the formation, the modulation, and the breaking of chemical bonds. Movies of a laser-induced pi-pi* transition and of a proton-molecule scattering process will be presented. (iii) Optimal-control theory will be generalized to treat time-dependent targets. In this way, the time-dependent density may be controlled directly. (iv) Finally, a novel approach treating molecular electronics with TDDFT will be shown.