Berlin 2005 – scientific programme

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MO: Molekülphysik

MO 34: Theory II

MO 34.3: Talk

Monday, March 7, 2005, 15:00–15:15, HU 2097

Bonds in Motion: The Time-Dependent Electron Localisation Function — •E. K. U. Gross, T. Burnus, and M. A. L. Marques — Institut für Theoretische Physik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

The so-called electron localization function (ELF) provides a useful way to visualize the degree of localization of the electron distribution. It thereby allows for a topological classification of the different types of chemical bonds. The ELF 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 a reference electron with the same spin at r. In this work, the concept of the ELF will be generalized to the time-dependent domain. Compared with the static version, the time-dependent ELF contains an additional current-dependent term which arises from the phases of the time-dependent Kohn-Sham orbitals. Movies of the time-dependent ELF allow the time-resolved observation of the formation, the modulation, and the breaking of chemical bonds, and can thus provide a visual understanding of complex reactions involving the dynamics of excited electrons. We illustrate the usefulness of the time-dependent ELF by two examples: A π − π^* transition in acetylene induced by a laser field, and the destruction of bonds and the formation of lone-pairs in scattering a high-energy proton from ethylene.