Berlin 2014 – scientific programme
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MO: Fachverband Molekülphysik
MO 15: Experimental Techniques 3
MO 15.4: Talk
Thursday, March 20, 2014, 11:15–11:30, BEBEL SR144
Methods to simulate light propagation and optical response in small metal cluster aggregates — •Polina Lisinetskaya1 and Roland Mitric2 — 1Fachbereich Physik, Freie Universität Berlin, Arnimallee 14, D-14195 Berlin, Deutschland — 2Institut für Physikalische und Theoretische Chemie, Universität Würzburg, D-97074 Würzburg, Deutschland
We present a method of the simulation of the optical responce and light propagation in ordered arrays of small noble-metal clusters with discrete electronc structure. The description of the systems is based on the excitonic Hamiltonian constructed employing the TDDFT electronic states of the individual subunits and the dipole-dipole interaction between them. The time evolution of the systems is studied by numerical solution of the time-dependent Schrödinger equation with the excitonic Hamiltonian perturbed by an external laser field. For each subunit the time-dependent dipole moment is calculated using the reduced density matrix formalism. Such quantum-mechanically determined dipole moments are used to simulate the spatio-temporal distribution of the electric field produced by the array. Additionally, we introduce an approximate self-consistent iterative approach to treat arrays consisting of many subunits. The developed methodology is illustrated first on the example of Ag2 and Ag8 cluster pairs. Subsequently, light propagation in a triangular-shaped array consisting of six Ag8 clusters is simulated. Finally, the possibility of optimal control of light propagation in a T-shaped structure formed of seven Ag8 clusters is demonstrated.