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This paper describes the photomodification of borosilicate glass substrates assembled with 40 nm diameter gold nanoparticles (Au NPs) with surface coverages ranging from 17 to 23% on excitation of the localized surface plasmon band of the NPs with a 532 nm nanosecond pulsed-laser beam. The laser irradiation allowed the splitting and fusion of NPs on the substrate surface and, at the same time, the formation of craters of less than 10 nm diameter at various places following one laser shot with a relatively high intensity of 460 or 370 mJ • cm -2 • pulse -1 but well below the breakdown threshold of 25-40 J • cm -2 • pulse -1 . The formation of the craters was more and more distinctly observed by continuous irradiations. The number density, average diameter, and the surface coverage of the craters were not linearly dependent on the laser shot number but exhibited the saturation behavior due to the consumption of Au NPs. The threshold laser energy for the crater formation was dependent on the accumulated number of laser shots: a greater number of laser shots were necessary to form craters as the laser fluence decreases. Most interestingly, the laser-irradiated areas of the substrate exhibited a greater susceptibility to the wet chemical etching with aqueous hydrogen fluoride. The mechanism of the laser modification and a possible application to nanofabrication on glass surfaces by utilizing Au NPs were discussed on the basis of the scanning electron microscopy (SEM) observation as well as the extinction and light scattering spectroscopic measurements.

Quenching of photoexcited triplet-state anthracene through triplet-triplet (T-T) energy transfer mechanism by a few energy acceptors, azulene, ferrocene, and also anthracene in the ground state, is investigated in a dehydrated Na + form of zeolite Y (NaY) with a transient absorption spectroscopy utilizing a diffuse reflectance detection technique. It is found that the decay curves of T-T absorption for anthracene follow unconventional kinetics that can be handled by a model based on the continuous time random walk (CTRW) theory. The analysis of the quenching kinetics affords an estimate of the intrazeolite self-diffusion coefficient for the guest aromatic species. Presently, a simplified version of the CTRW treatment is developed which enables us to extract information concerning the diffusivity only by analyzing the long time tail of triplet decay signals measured by a conventional photomultiplier detection system with limited time resolution. The self-diffusion coefficients thus obtained, ranging from 10 -15 to 10 -16 m 2 s -1 in NaY at 298 K, are significantly smaller than those observed for benzene (10 -10 -10 -13 m 2 s -1 ). This study demonstrates that the triplet quenching method is a powerful technique for evaluating diffusion coefficients of relatively large organic molecules with small intrazeolite mobility that are hardly measurable by NMR and other traditional techniques.