Table of Contents
Laser Chemistry
Volume 17, Issue 3, Pages 161-174
http://dx.doi.org/10.1155/1997/10561

Non-linear Simultaneous Two-Photon Excitation Energy Transfer in the Wrong Direction

Institute of Organic and Bioorganic Chemistry, Humboldt University, Hessische Str. 1-2, Berlin D-10115 , Germany

Received 23 October 1996

Copyright © 1997 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The simultaneous two-photon excitation energy transfer (SEET) was demonstrated for the first time using trichromophoric model compounds. Two identical donors (A–antenna) were covalently linked to an energy acceptor unit (T–target) with different energy levels preventing energy transfer of a single photon. At high intensity illumination (laser exposure) of a trichromophoric system A∼T∼A (A–fluorescein, erythrosin; T-Estilbene), sufficient to excite both of the appended donor subunits, population of the target excited state may occur via simultaneous energy transfer of two photons, one from each donor. In order to restrict reverse energy transfer from the higher energy target to the lower energy donor(s) it is necessary that the excited target unit undergoes an efficient photoreaction. In the investigated case this was achieved by photoisomerization of the stilbene unit used for monitoring of the SEET.