ORIGIN OF THE SATURATION OF THE 3RD-ORDER OPTICAL NONLINEAR RESPONSE OF ONE-DIMENSIONAL CONJUGATED SYSTEMS

The coupled quantum oscillator model is applied to the evaluation of c onformational effects in thiophene and polyene oligomers. Thermochromi sm measurements on heptathiophene are presented and modeled. The effec t of conformation is also studied in recently published nonlinear opti cal experiments on polyene oligomers. It is shown that the model accou nts for a masterplot which summarizes the length dependence of the opt ical properties of conjugated molecules. (C) 1997 Elsevier Science B.V .