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Dynamics in fullerene C60

Focus

The study of the interactions between strong laser pulses and matter has known a dramatic development since the past years and it has been realized that it gives access to the electronic properties of matter. In particular, the study of the mechanisms of ionization of atoms and small molecules have been very fruitful, both theoretically and experimentally. Then, the road is open to the extension of these studies to more complex systems, such as macromolecules. In particular, fullerene C60, which roughly looks like a soccer ball, is a first step in this direction: The molecule has a significant spatial extension while its geometry enables one to consider relatively simple models.
First we consider a single electron model of the molecule. The particularity of the model is the presence of very stiff parts in the effective potential (see figure). As a first approximation, we replace the stiff wall by infinite vertical walls where elastic rebounds happen (see blue trajectory on the bottom plane). The resulting dynamics corresponds to a billiard of which we study the dynamical properties when the laser is circularly polarized.

Associated publication

Annular billiard dynamics in a circularly polarized strong laser field

posted May 14, 2016, 12:40 PM by François Mauger   [ updated May 14, 2016, 12:40 PM ]

Abstract

We analyze the dynamics of a valence electron of the buckminsterfullerene molecule (C60) subjected to a circularly polarized laser field by modeling it with the motion of a classical particle in an annular billiard. We show that the phase space of the billiard model gives rise to three distinct trajectories: “whispering gallery orbits,” which hit only the outer billiard wall; “daisy orbits,” which hit both billiard walls (while rotating solely clockwise or counterclockwise for all time); and orbits that only visit the downfield part of the billiard, as measured relative to the laser term. These trajectories, in general, maintain their distinct features, even as the intensity is increased from 1010 to 1014 W cm−2. We attribute this robust separation of phase space to the existence of twistless tori.

Reference

A. Kamor, F. Mauger, C. Chandre, and T. Uzer - Annular billiard dynamics in a circularly polarized strong laser field - Physical Review E 85, 016204 (2012)

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