Analysis and control of electron dynamics with time-dependent density functional theory

by Prof. E. K. U. Gross (Freie Universität Berlin, Germany)

Tuesday 17 Jun 2008, 16:00 → 18:00 Europe/Rome

Aula M. Conversi (Dip. Fisica Edificio G. Marconi)

Modern density functional theory is based on the surprising fact that knowledge of the ground-state density alone is sufficient to calculate all physical observables of a stationary quantum system. Time-dependent phenomena, however, are not accessible within the standard framework of density functional theory. In this lecture, the time-dependent generalization of density functional theory (TDDFT) will be presented. After an overview of the basic concepts of TDDFT recent developments beyond the linear-response regime will be presented. In particular, we will describe the visualization and analysis of electronic motion by means of the so-called electron localization function (ELF). The ELF provides a way to visualize chemical bonds. It is derived from the conditional probability of finding an electron in the vicinity of a point r if one knows with certainty that there is another electron with the same spin at r. The shape of the ELF (as function of r) allows a topological classification of the different types of chemical bonds. Here we generalize the ELF to the time-dependent case. Two movies of the time-dependent ELF will be presented, one that shows the formation and breaking of chemical bonds in a proton-ethylene scattering process and another one that visualizes a laser-induced π-π* transition in acetylene in a time-resolved fashion. To give a feeling of the broad and powerful scope of the method, we will sketch a few further applications of the method such as the transport of electrons through nano-scale systems an their control by shaped laser pulses.