The luminescence spectra and the lifetime of tris(2,2′-bipyridine)ruthenium(II), Ru(bpy) 3 2+ , were studied in the sol-gel reaction system of tetramethoxysilane (TMOS) at room temperature. The luminescence peaks and lifetime were considerably altered by the nature of the sol-gel matrix. These findings are discussed in connection with adsorption of Ru-(bpy) 3 2+ on gels and lower temperature measurements at 77 K.

No abstract

The fluorescence spectra of 7-azaindole were studied in a mixed solution of Si(OC2H5)4, H20, and ethanol, which reacts to form silica gel glass, i.e., porous Si02. Significant shift in the fluorescence (380-430 nm in Xmax) was observed, mainly during the gel-xerogel stages. Fluorescence, fluorescence excitation, and absorption spectra indicated that 7-azaindole forms a hydrogen-bonded complex with ethanol in the solution and finally forms a complex of stronger hydrogen bonds with silanol in the xerogel. They also show that the large shift in fluorescence is attributed not to the stabilization in the ground state but to that in the excited state. We consider the large shift in the fluorescence spectra can be explained by the interaction between the 7-azaindole complex with silanol and a large number of polar silanol groups which surround the complex. In addition, fluorescence spectra reveal that a double proton transfer reaction occurs in the sol-gel stages and, possibly, in the xerogel.

The fluorescence spectra of 9-anthracenecarboxylic acid (9ACA) were studied in surfactant solutions of sodium dodecyl sulfate and Triton X-100 as a function of surfactant concentration. In addition to an anthracene-like sharp fluorescence, a broad fluorescence with a peak around 470 nm appeared at 330 nm excitation above critical micellar concentrations. Only a broad fluorescence was seen at 400-nm excitation. Based on the excitation and absorption spectra, the broad fluorescence is thought to be caused by hydrogen-bonded dimers dissolved in the micelles. Intercalation of 9ACA was done for two alkylammonium-montmorillonites. The fluorescence spectra of 9ACA showed a broad peak with increase in loading levels of 9ACA in the alkylammonium-montmorillonites. The fluorescence was not similar to the excimer in a head-to-head configuration with a maximum at 510 nm observed in the crystals, but rather to the broad one in the micelles. Therefore, the hydrogen-bonded dimers are also attributed to the origin of the broad fluorescence in the interlayer spaces.

No abstract

No abstract

Abstract. Hylleraas wave functions composed of the optimally combined N terms (2 < N < 20) are presented for two-electron atoms with nuclear charges Z = I ( H ), 2(He), 3(Li~), 5(B3+), and 10(NeS+). The sphericallyaveraged electron density p(r) and electron-pair density h (r12) are constructed in a simple and analytical functional form from the 20-term functions. Comparison of several one-and two-electron moments (r k) and (r~2) shows that the present density functions have near-exact accuracy.

No abstract