Düsseldorf 2007 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
A: Fachverband Atomphysik
A 12: Poster I - Interaction with external fields
A 12.5: Poster
Dienstag, 20. März 2007, 16:30–18:30, Poster B
Switching in endohedrals through an external static field — •Paula Rivière1, Jan-Michael Rost1, and Mohammed Madjet2 — 1Max-Planck-Institut für Physik komplexer Systeme, Dresden — 2Institut für Chemie, Freie Universität Berlin
Endohedral fullerenes M@C60, where an atom M is trapped inside a hollow fullerene cage C60, have arisen significant interest in the last years, due to their unique properties. For example, the C60 cage acts as a Faraday cage protecting the quantum state of the inner atom, which can be useful for future applications. The fullerene also acts as a resonance cage, since collective effects lead to resonances in the photoionization cross sections of encapsulated atoms. The equilibrium position, re, of different inner atoms inside the cage has also been studied. However, a future use of endohedrals as stable quantum systems requires a control of the quantum state of the inner atom.
Maybe the simplest way of changing the state of the inner atom is changing its position within the cage. In fact, during illumination of an endohedral with (weak) laser light, the polarization of the electronic cage changes. In response, the inner atom alters its position. We have studied this process within the linear response theory, for M = Li+, Na+, and K+. The fullerene is described within DFT, using the jellium model. The effect of polarization on re is obtained from the minimum of the potential, which has a repulsion-dispersion contribution and a polarization contribution. A switching process in re can be observed as a function of the energy of the external field, with special structures centered at the position of the surface and volume resonances of C60.