Through calculating the electron transfer reaction parameter between xanthene dye and diphenyl iodonium, the dynamic power of fluorescein yellow was found to be the highest among xanthene dyes. And electron transfer was proved to be the only possible path to realize the photosensitization. By the investigation of absorption spectrum of photosensitive system, the influence of valence bond structure, solvent effect and initiator concentration on the absorption spectrum was examined. The results show that the absorption peaks were red shifted with the increase of solvent polarity, and blue shifted with decrease of solvent polarity. In the nonpolar solvent, the higher the concentration of initiator, the higher the degree of dissociation, and the more the free ion will appear.

Key words: electron transfer, absorption spectrum, solvent effect