Theoretical Studies on the Third-order Nonlinear Optical Properties and Two-photon Absorption of Stilbene Derivatives

Different types of stilbene derivatives (D-p-D, A-p-A, D-p-A) were investigated with AM1, and specially, equilibrium geometries of symmetrical stilbene derivatives (D-p-D) were studied using of PM3. With the same method INDO/CI, the UV-vis spectra were explored and the position and strength of the two-photon absorption were predicated by Sum-Over-States expression. The relationships of the structures, spectra and nonlinear optical properties have been examined. The influence of various substituents on two photon absorption cross-sections was discussed micromechanically.