Abstract

α,ω-Diphenylpolyenes have attracted a great deal of attention because of an extremely high excited state third-order nonlinearity of the first three members of the homologous series, transstilbene, diphenylbutadiene, and diphenylhexatriene (DPH).^1-3 Within the series these molecules exhibit a reversal of their 1¹B_u and 2¹A_g levels as the lowest excited singlet state. This opens up the unique opportunity to study mixing effects, e.g., energy transfer between the excited singlets near degeneracy. In DPH the relaxation of the initially formed 1¹B_u state to a 1¹B_u/2¹A_g equilibrium mixture as well as the kinetics of the transients investigated by picosecond time-resolved absorption and fluorescence spectroscopy is still the subject of controversy.^3-6

© 1998 Optical Society of America