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1

Temperature Dependence of Luminescence Decay from the ^{4}G_{5/2} State of Sm^{3+} in Cs_{2}NaSm_{x}Y_{1-x}Cl_{6} and Cs_{2}NaSm_{x}Eu_{y}Y_{1-x-y}Cl_{6}

100%

Luxbacher T., Fritzer H., Flint C.

Acta Physica Polonica A

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1996

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vol. 90

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issue 2

307-313

EN

Luminescence decay curves for the ^{4}G_{5/2} → ^{6}H_{7/2} emission of Sm^{3+} in the cubic hexachloroelpasolite crystals Cs_{2}NaSm_{x}Y_{1-x}Cl_{6} (x=0.005 to x=1) and Cs_{2}NaSm_{x}Eu_{y}Y_{1-x-y}Cl_{6} (x=0.01 to x=0.95, y=0.05 to y =0.99) have been measured over the temperature range 10 K to 300 K using pulsed laser excitation into the ^{4}G_{5/2} state of Sm^{3+}. The luminescence from this state is strongly quenched by cross relaxation to Sm^{3+} acceptors and energy transfer to the ^{5}D_{0} state of Eu^{3+}. The temperature dependence of cross relaxation and of energy transfer is discussed in terms of the involved mechanisms.

2

Effects of Solute-Solvent Interactions on Radiationless Decay of Thioketones Excited to Their S_{2}- and T_{1}-States

100%

Szymański M., Balicki M., Binkowski M., Kubicki J., Maciejewski A., Pawłowska E., Wróżowa T.

Acta Physica Polonica A

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1996

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vol. 89

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issue 4

527-546

EN

Spectral and photophysical properties of a few aromatic thioketones in their S_{2}- and T_{1}-states, in particular those determined by their interactions with solvents, are discussed. The reasons for a drastically different behaviour of thioketones in interactions with benzene as well as saturated hydrocarbons and perfluoroalkanes are analysed in more detail. Results of the time-resolved transient absorption measurements in the pico- and nanosecond time scale are given. An analysis of these results proves that a product of the decay of the S_{2}-state of xanthione in benzene is a new transient (τ_{1/e} ≥ 60 ps) individuum which, regarding the system properties and the conditions of the experiment, has been identified as an exciplex in S_{2}-state formed as a result of an efficient interaction with benzene molecule. Also in xanthione//alkane systems the involvement of a transient individuum was proved. Most probably, this individuum was a thioketyl radical which could be formed by hydrogen abstraction from a hydrocarbon molecule by xanthione in the S_{2}-state. Such individua act as intermediates in passing excitation to the triplet states of thioketones and are effective channels of the S_{2}-state decay. The changes observed in the transient absorption spectra of xanthione in C_{6}H_{6} in the time range of 10^{-7}-10^{-6} s can be attributed to the formation of an excimer in the T_{1}-state as a result of the T_{1}-state selfquenching.

3

Electron-Phonon Coupling in Rare Earth Compounds

100%

Meijerink A., Blasse G., Sytsma J., de Mello Donega C., Ellens A.

Acta Physica Polonica A

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1996

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vol. 90

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issue 1

109-119

EN

The variation in electron-phonon coupling strength for rare earth ions has been studied by measuring vibronic transition probabilities and temperature dependent line broadening for a large number of rare earth ions in different host lattices. The results show a large variation in the electron-phonon coupling strength (almost three orders of magnitude) and a remarkable trend: the coupling is strong for ions in the beginning and at the end of the lanthanide series and weak in the middle. In covalent host lattices the coupling is much stronger than in ionic host lattices. An explanation of the results is given and the consequences of the variation of the electron-phonon coupling strength on phenomena like multiphonon relaxation, energy transfer and cooperative luminescence are discussed.

4

Spectroscopic Study of Rare Earth Chromates: Relation to the Structure

100%

Antic-Fidancev E., Lemaitre-Blaise M., Parada C.

Acta Physica Polonica A

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1996

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vol. 90

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issue 1

33-44

EN

The luminescence spectra of the trivalent europium ion embedded in various rare earth chromates were analyzed. The spectroscopic data in most of chromates are in agreement with the structural determination but for some others the discrepancy between two methods is underlined. Energy level schemes were deduced from the experimental emission spectra and the crystal field simulation has been performed. The maximum splitting of the ^{7}F_{1} manifold of the Eu^{3+} ion as a function of N_{v}, the so-called crystal field strength parameter, is given. This allows us to classify the compounds according to their crystal field extent.

Refine search results

4 Acta Physica Polonica A

4 1996

1 Antic-Fidancev E.

1 Balicki M.

1 Binkowski M.

1 Blasse G.

1 Ellens A.

1 Flint C.

1 Fritzer H.

1 Kubicki J.

1 Lemaitre-Blaise M.

1 Luxbacher T.

1 Maciejewski A.

1 Meijerink A.

1 Parada C.

1 Pawłowska E.

1 Sytsma J.

1 Szymański M.

1 Wróżowa T.

1 de Mello Donega C.

Temperature Dependence of Luminescence Decay from the ^{4}G_{5/2} State of Sm^{3+} in Cs_{2}NaSm_{x}Y_{1-x}Cl_{6} and Cs_{2}NaSm_{x}Eu_{y}Y_{1-x-y}Cl_{6}

Effects of Solute-Solvent Interactions on Radiationless Decay of Thioketones Excited to Their S_{2}- and T_{1}-States

Electron-Phonon Coupling in Rare Earth Compounds

Spectroscopic Study of Rare Earth Chromates: Relation to the Structure