Hannover 2003 – wissenschaftliches Programm
MO 6.7: Poster
Dienstag, 25. März 2003, 16:00–18:30, Lichthof
The J-Band of Organic Dyes: Lineshape and Coherence Length — •Alexander Eisfeld — Fakultät für Mathematik und Physik, Universität Freiburg, Hermann-Herder-Strasse 3, D-79104 Freiburg
Self-organised J-aggregates of dye molecules, known for over 60 years, are emerging as remarkably vertasile quantum systems with applications in photography, opto-electronics, solar cells, photobiology and as supra-molecular fibres.
Recently there has been much effort to achieve quantum entanglement and coherence on the nanoscale in atom traps and quantum dot aggregates (for use in quantum computing). We point out that the excitonic state of the J-Aggregate is a text-book case of mesoscopic quantum coherence and entanglement. The establishment of coherence can literally be seen since the dye changes color dramatically on aggregation due to strong shifts in the absorption spectrum.
Here we reproduce in a simple theory the shifts and shapes of absorption spectra upon aggregation to a polymer and calculate the coherence length of quantum entanglement of monomer wavefunctions .
 A. Eisfeld, J.S. Briggs, Chem. Phys. 281, 61 (2002)