Theoretical investigation on dendritic molecules with large two-photon absorption cross section

The two-photon absorption (TPA) properties of a class of dendritic molecules have been theoretically investigated by using the AM1 and ZINDO methods. The calculated peak TPA cross section values (delta(max)) are from 2615.36 X 10(-50) cm(4) s/photon to 102222 X 10(-50) cm(4) s/photon. To the best of our knowledge, the gained TPA cross sections are ones of the highest TPA cross section values reported so far. It is found that there is a linear relationship between the maximal TPA cross section and the number of repeated units in chromphores, however, the position of the maximum one-photon absorption peak nearly maintains a constant. This result suggests that it is possible to obtain larger TPA cross section values at no cost of the transparency by means of increasing the number of repeated units in molecules. (C) 2004 Elsevier B.V. All rights reserved.