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The effect of isovalent chemical substitution of [Eu.sup.3+] into the [Tb.sup.3+] sites on the magnetic and electrical properties of ([Tb.sub.1-x][Eu.sub.x])Mn[O.sub.3] (0 less than equal to x less than equal to 1.0) system is examined. The results have shown that the increase in the Eu content has increased both the tolerance factor and Mn-O bond distance, leading to the reduction in the octahedral distortion and Jahn-Teller (JT) effect.

The electron-transfer (ET) fluorescence quenching of aromatic hydrocarbons by trivalent lanthanide ions M(super 3+) [europium ion Eu(super 3+) and ytterbium ion Yb(super 3+)] and the ET reactions of the geminate and free radical recombination are studied, to understand the effects of molecular size on photo induced ET reactions. It is observed that the shift of the switchover of the fluorescence mechanism, yielding the geminate radical ion pairs, is due to the difference in their molecular size of the quenchers.

Two models based on detailed rate equations are presented to describe the dynamics of Q-switched clad-pumped Er(super 3+) -Yb(super 3+) codoped fiber lasers. The full wavelength-dependent model is considered as a standard, and the simplified model is derived from it by assuming single wavelengths in both 1080- and 1550-nm bandwidths.

Continuously illuminated single europium ions incorporated in d [Eu (super 3+): Y2O3] nanocrystals (5-15 nm diameter) undergo on-off blinking on a variable time scale ranging from hundreds of milliseconds to several seconds. The study indicates the first report of fluorescence imaging of single rare-earth ions in metal oxide nanoparticles, and the first observation of multiple bright states in the luminescence of a single chromophore.

A methacrylate copolymer containing electron donor-acceptor (D-A) moieties and europium complexes (PCzOxEu) in the pendant groups is synthesized and characterized. Molecular simulations are carried out to elucidate the roles of oxadiazole moieties in improving the response time and retention time of the memory device.

Rodlike, olivelike, pineapplelike, and particlelike nanocrystals of the YV[O.sub.4]:Eu is synthesized by a hydrothermal reaction with different conditions, respectively. The analysis has suggested that the function-improved materials can be obtained by tailoring the size and shape of the YV[O.sub.4]:Eu nanostructures.

The surface pressure area isotherm measurements show that the complex forms a stable Langmuir film at the air water interface without adding any electrolytes into the subphase. The Langmuir-Blodgett films are studied by UV-visible, infrared, and emission spectroscopies, atomic force microscopy, and cyclic voltammetry.

The photoelectron spectra of the multiple-decker 1:1 sandwich clusters of Eu(sub n)[COT](sub n)(super -) (n=1-4) where COT=1,3,5,7-cyclooctatetraene synthesized in the gas phase and the bonding scheme, charge distribution, valence orbital energies and others were studied theoretically. The result showed that the characteristic behavior of the spectra is due to the strong ionic bonding and the charge distribution.

The unusual green photoluminescence (PL) of the N,N-dimethylformamide (DMF)/hydrochloric acid (HCL)/europium chloride solutions was investigated to clarify the emission mechanism. The result showed that the DMF/HCL pair alone can yield a green PL band under UV excitation and the emissions has features of that of excimers.

Radiative and energy-transfer processes in LiGd1-Xf4:Eu(power 3+)(sub x) are studied by time-resolved luminescence spectroscopy. The luminescence lifetimes of Gd(power 3+) ([power 6]P[sub 7/2]) and Eu(power 3+) ([power 5]D[sub o]) were estimated to be ca. 1.5 ms and ca. 8ms, respectively.

The measurement of the rate constants for decay of the Eu(super 3+)(super 5)D(sub 0) excited state for Eu(apa)(sub n) with n = 0-3 in H(sub 2)O and D(sub 2)O at 295 K is reported. The electronic energy exchange between species with differing numbers of coordinated diplicolinate ligands was examined and was found to be significant for species of opposite charge.