Time-resolved resonance Raman study of biphenyl occluded in the supercagesof faujasitic zeolites

The laser photolysis (248 nm, 20 ns) of biphenyl (BP, S-0) occluded in the void space of faujasitic zeolites (Na(n)FAU), Na-n(SiO2)(192-n)(AlO2)(n) wi th n = 0, 56, 85 has been studied by time-resolved resonance Raman spectros copy combined with time-resolved diffuse reflectance UV-visible absorption spectroscopy in the ns - mu s time scale. The excitation (370 nm, 8 ns) of the RR scattering in the wavelength region of the UV electronic absorption of the transient species provides clear evidence of the radical cation (BP (+) ) as major species for zeolites Na(n)FAU (n = 56, 85). The amount of tr iplet state (BP, T-1) depends on the aluminum content and in a less extent on the fluence of the pump laser at the sample.