ABSTRACT
Experimental Details . . . . . . . . . . . . . . . . . . . . . . . . 368
Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . 368
Sample Preparation . . . . . . . . . . . . . . . . . . . . . . . 368
Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . 369
Photophysics of Pyrene on Various Silica
Gel Surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369
Photophysics of 1-Aminopyrene on Various
Silica Gel Surfaces . . . . . . . . . . . . . . . . . . . . . . . 369
Gaussian Distribution Model . . . . . . . . . . . . . . . . 372
Oxygen Quenching of Singlet Excited States
of Pyrene and DPA . . . . . . . . . . . . . . . . . . . . . . 374
Oxygen Adsorption Isotherms . . . . . . . . . . . . . . . 375
Langmuir-Hinshelwood Approach
to Oxygen Quenching . . . . . . . . . . . . . . . . . . . . 376
Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 376
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . 377
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 377
Time-resolved and steady-state fluorescence probing was used to study gas-solid and liquid-solid silica
gel interfaces. The molecular surveying probes pyrene, 1-aminopyrene, pyrenecarboxylic acid, and 9,10-
diphenylanthracene adsorbed at the silica gel surface give information about probe environment, mobility,
and accessibility. Reactions of surface-bound arene singlet excited states with molecular oxygen were
monitored over a range of temperatures; the reactions were assigned to a unique Langmuir-Hinshelwood
mechanism. The kinetics reflect the details of oxygen adsorption and movement on the silica gel surface.
