Formation mechanism of anthracene dimers and excimers in NaY zeolitic nanocavities

Abstract

The dimer and the excimer formation mechanisms of anthracene in NaY zeolitic nanocavities have been studied by using various spectroscopic techniques of 129Xe NMR, diffuse reflectance, and emission as well as time-resolved fluorescence. Two anthracene molecules adsorb concertedly into a zeolitic supercage to form a ground-state stable dimer. An excited monomer in a singly occupied supercage gives birth to an excimer if another monomer exists in a tetrahedrally connected nearest supercage. An excited monomer forms a nonluminescent ion pair with a monomer in a nearest supercage by transferring an electron within 100 ps. The dark intermediate rearranges to transform into an excimer on the time scale of 400 ps.