Regensburg 2002 – wissenschaftliches Programm
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O: Oberflächenphysik
O 25: Teilchen und Cluster
O 25.10: Vortrag
Dienstag, 12. März 2002, 18:30–18:45, H45
Femtosecond electron dynamics in metallic clusters from time-dependent Hartree-Fock theory — •Yaroslav Pavlyukh and Wolfgang Hübner — Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, D - 06120, Halle, Germany
The possibility to experimentally investigate the ultrafast electron dynamics in clusters motivated us to develop a theoretical method, that is capable on the one hand to correctly describe the energy level scheme and electron-electron interactions, and on the other hand to show this in a way closest to experiment, i.e. resolved in time. We developed a new computational scheme, that describes the state selective electron dynamics in clusters under the influence of the external laser field within the mean-field approximation. The solution of the time-dependent Hartree-Fock equation is performed using the restricted Hartree-Fock functional for closed-shell systems, an expansion in Gaussian-type basis functions and employing an effective core potential for the inner electrons. We obtain information about collective excitations and relaxation processes in the Na4, Na9+, and Pt3 clusters analyzing the time evolution of the power spectrum of the dipole moment within a mean-field approach. For the Pt3 cluster, in which electron-electron relaxation mechanism is as important as in bulk metals, our ab initio theory yields a relaxation time of 24 fs in agreement with recent experimental results [N. Pontius et al., Phys. Rev. Lett. 84, 1132 (2000)]. Due to the basis-set expansion of the wave function our method is capable to follow the dynamics not only of the whole electron cloud, but of any particular molecular orbital.