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Illustrates how a qualitative description of the geometry and electronic characteristics of homogeneous metal clusters can be obtained using semiempirical MO (molecular orbital theory) methods. Computer applications of MO methods to inorganic systems are also described. (CS)

Focuses on a study that investigated the mediation of surface recombination in a II-VI powder palladium microislands. Details of the experiment; Results and discussion; Conclusions.

Presents a study which derived a version of the dead-layer model to describe the luminescence behavior of a metallized zinc (cadmium) sulphur: silver phosphor powder. Experiment; Results; Conclusions.

Electron transfer quenching of the fluorescence of rhodamine-6G in polyvinyl acetate and poly-α-methylstyrene films by aromatic amine quenchers has been examined, using both steady-state and time-resolved methods. Observed quencher concentration dependences do not conform to expectations from either the simple Perrin or Stern–Volmer models. The steady-state quenching results are consistent with long-range electron (tunnel) transfer, with collective quenching at higher quencher concentration, but existing models of this process do not quantitatively rationalize our results. Some potential difficulties with these models are accordingly discussed. Time-resolved (streak camera) experiments confirm that all the quenching events are of dynamic origin, to the exclusion of the involvement of a fractional population of fluorescence-inactive absorbers owing to ground-state complex formation. [ABSTRACT FROM AUTHOR]

Presents information on a study which observed optical limiting behavior in silver bromide nanosols. Experimental procedure; Results; Discussion.

Examines the photophysics of a Zn(Cd)S:Ag phosphor, in powder form under ambient conditions, over a time domain extending from picoseconds to milliseconds. Implications of experimental results for energy conversion schemes involving photoassisted catalysis; Kinetics of appearance and disappearance of photoconductive transients in powders under ambient conditions; Reflection spectrum of a deposit of the Zn(Cd)S:Ag powder.

We have probed the photophysics of nanoparticulate TiO2 using hyper-Rayleigh scattering (HRS) spectroscopy. We find that despite its Wurtzite structure, the anatase particles we prepared are only weakly hyperpolarizable, which suggests that second harmonic generation may couple transitions which are: (a) only weakly allowed, i.e. indirect; or (b) associated with states, probably surface states, of low density. Addition of a carboxy-functional spectral sensitizing dye further quenches second harmonic generation. We hypothesize that the dye competes efficiently with hyperpolarizable surface states for capture of photoholes. We also found that HRS could be used to follow formation of these photocatalyticallly active nanoparticles by acid-catalyzed oxopolymerization of Ti(O1Pr)4. The polymerization is a pseudo-first order process consistent with occurrence of an S(N)1 reaction at Ti(IV) in the rate determining step.