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1
Content available remote

Simple Parametrization Scheme for Electric Dipole Intensities

100%
Gajek Z.
Acta Physica Polonica A
|
1993
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vol. 84
|
issue 5
875-880
EN
A simple phenomenological model for the electric dipole intensities of nf → nf transitions is proposed. The model is derived by adopting of the common angular overlap model to the generalized Judd-Ofelt theory of the static coupling mechanism. It leads to reduction of a number of the effective intensity parameters to six, three of which correspond to the f → d excitations and the remaining to the f → g ones. Calculations performed for some lanthanide complexes show that the model, despite its inborn crudeness, provides satisfactory results and may be a convenient tool for a preliminary estimation of intensities. Regularity of the obtained parameters indicates a possibility of further reduction of their number.
2
Content available remote

Optical Properties of Lanthanide Squarates

100%
Huskowska E., Legendziewicz J., Drożdżewski P.
Acta Physica Polonica A
|
1996
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vol. 90
|
issue 2
447-453
EN
Two types of lanthanide squarate hydrates of formulae Eu(C_{4}O_{4})(HC_{4}O_{4})(H_{2}O)_{6}·H_{2}O (compound I) and [Ln_{2}(C_{4}O_{4})_{3}(H_{2}O)_{8}] where Ln = Eu and Gd (compound II) were investigated. The optical properties of crystals I and selected spectral data of compound II are reported and confronted with earlier studies of europium complexes type II. Excitation and emission spectra were measured at 77 K. Effect of polymeric structure on spectroscopic properties is considered and correlated with the structural data. Cooperative intrachain interactions between metal ions coupled via squarate anions were pointed and cooperative absorption was recorded. To check the presence of the Eu^{2+} traces, the EPR and γ-irradiation measurements were applied. Raman spectra of the compound II (where Ln = from Sm to Lu) were measured in the range 50-500 cm^{-1}. Positions of the bands were considered in function of ionic radius of lanthanide ion. The above, together with the data from excitation spectra, allows to localize the Ln-O bands. Vibronic components in electronic spectra were elucidated and assigned.
3
Content available remote

Carrier-Influenced Bistable Behaviour in Ring Cavity Configuration

100%
Nguyen A., Nguyen D., Hoang N.
Acta Physica Polonica A
|
1992
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vol. 81
|
issue 4-5
517-525
EN
Bistable output-input light characteristics in the exciton spectral region have been examined in a ring cavity configuration taking ito account the influence of the presence of free carriers in the cavity as well as of the density-dependence of the exciton damping. The resulting modifications could serve as a means to optimize the optical bistable device operation.
4
Content available remote

Optical Properties of HgMgMnTe Crystals

80%
Frasunyak V., Gavaleshko M., Orletskii I.
Acta Physica Polonica A
|
1995
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vol. 87
|
issue 1
237-240
EN
Optical properties of new semimagnetic semiconductors of Hg_{1-x-y}Mg_{x}Mn_{y}Te (x < 0.10, y < 0.10) in the fundamental absorption region at T = 290 K and 80 K were investigated. A shift of absorption band edge was revealed when composition and temperature changed. The energy gap and its temperature coefficient were evaluated as well as ana­lytical expressions which describe E_{g}(x,y,T) for quaternary solid solutions were analysed.
5
Content available remote

Spectroscopic Studies of PrBr_{3}·7H_{2}O Monocrystal

80%
Oczko G., Legendziewicz J., Hanuza J., Gliński J., Macalik L.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 2
431-438
EN
Single crystals of praseodymium tribromide heptahydrate were grown from aqueous solution. The IR, Raman, and high resolution absorption spectra were measured at room and low temperatures. The assignments of IR and Raman frequencies are reported. The temperature dependence of intensities was found and vibronic coupling in f-f transitions was analysed. Anisotropy of the intensities of optical lines was detected and taken into account in the Judd-Ofelt analysis of the f-f transitions probabilities. The results are compared to the available IR and electron spectroscopic data for other single crystals of lanthanide bromides.
6
Content available remote

Optical Properties of Europium Compounds with L- and DL-α-Alanine-Hydroxamic Acids

80%
Legendziewicz J., Gawryszewska P., Gałdecka E., Gałdecki Z.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 2
439-446
EN
Two of europium complexes with L- and DL-α-alanine-hydroxamic acids were synthesized. To our knowledge they are the first examples of X-ray and spectral data of lanthanide single crystals with hydroxamic acid derivatives. Both compounds consist of dimers in their structures, formed by two OH bridging groups of amino-hydroxamic acid molecules. Besides, two metal ions are chelated by CO and OH groups, forming five-membered rings. In the complex with L-ligand, different than in the DL-one, two additional perchloric acid molecules are included in crystal cavities and form hydrogen bondings with nitrogen and oxygen atoms of the ligand. Absorption, emission and excitation spectra were measured and analyzed at room and low temperatures. Structural effect of ligand chirality was found and its spectroscopic consequences are reported. The effect of the dimeric structure on spectroscopic properties is discussed.
7
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IR Dispersion of Liquid CH_{3}I. I. Optical Constants and Integrated Intensities

80%
Czarnecki M., Hawranek J.
Acta Physica Polonica A
|
1991
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vol. 79
|
issue 4
437-450
EN
The spectra of both components of the complex refractive index of liquid CH_{3}I were obtained in the infrared region using the thin film transmission method. Dispersion data and integrated intensities for principal bands were determined and discussed.
8
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Spectroscopic Studies of Neodymium and Europium Phosphoro-azo β-Diketonates

80%
Amirkhanov V., Ovchinnikov V., Legendziewicz J., Graczyk A., Hanuza J., Macalik L.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 2
455-460
EN
New complexes of lanthanides (Nd, Eu) with phosphoro-azo derivatives of β-diketones were synthesized. Optical properties of these compounds were investigated and confronted with the structure and single crystal spectra of different types of earlier reported lanthanide phosphoro-azo-β-diketonates. The exchange of the N-P-O-Me ligand group by the N-P-NR_{2} one plays only a minor role in binding character of lanthanide ions but strongly affects biological functions and properties of lanthanide systems. In vitro experiment on cytotoxicity of the samples was performed using 10T_{1/2}, L_{1}, MCF, DETA and Meω-132 cell lines.
9
Content available remote

X-Ray Absorption Near Edge Spectra for CdTe - Theoretical Study

80%
Oleszkiewicz J., Markowski R., Kisiel A.
Acta Physica Polonica A
|
1992
|
vol. 82
|
issue 2
323-328
EN
The theoretical band structure of the CdTe was calculated using conventional, ab initio, self-consistent, relativistic LMTO method. The projected density of states and the dielectric function were produced within the local density approximation. Spin-orbit coupling was included in the perturbation approach. X-ray absorption spectra for the Cd L_{1,3}- and Te L_{1,3}-edges were calculated and the results compared with experimental data. The teoretical results were obtained from the calculations with inclusion of k-dependent transition matrix elements, spin-orbit coupling, extended set of basis functions and finite lifetime of initial and final states. They were compared with other calculations which use common constant matrix element approximation. The work presents final conclusion concerning validity of using constant matrix element approximation within one-electron scheme.
10
Content available remote

Spectroscopic and Laser Properties of Different Materials Doped with Pr^{3+} Ions

80%
Mierczyk Z., Kaczmarek S., Kopczyński K., Frukacz Z., Pracka I., Łukasiewicz T.
Acta Physica Polonica A
|
1996
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vol. 90
|
issue 2
407-410
EN
Examined praseodymium doped crystals with 1 at.% of Pr^{3+} ions for Y_{3}Al_{5}O_{12} (YAG), SrLaGa_{3}O_{7} (SLGO) hosts and 3 at.% of Pr^{3+} ions for YAlO_{3} (YAP) hosts were produced using Czochralski method. The luminescence for the range of 200÷800 nm and absorption spectra for a wide range of 200÷6000 nm, for Pr^{3+}:YAG, Pr^{3+}:SLGO and Pr^{3+}:YAP crystals have been measured. A free-running laser emission of λ=0.744 μm for Pr:YAG and λ=0.729 μm for Pr:SLGO for two different transmissions of output mirrors has been obtained.
11
Content available remote

UV and Gamma Irradiation Effect in Spectroscopic and Lasing Properties of Er^{3+} doped Yttrium-Aluminium Garnet, Yttrium Orthoaluminate and Lithium Niobate Crystals

80%
Kaczmarek S., Pracka I., Mierczyk Z., Kopczyński K., Piramidowicz R., Malinowski M., Kisielewski J., Matkovskii A., Sugak D.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 2
411-418
EN
Optical features (absorption and luminescence spectra) for Er^{3+} doped yttrium-aluminium garnet (YAG), yttrium orthoaluminate (YAP) and LiNbO3 crystals as well as their changes after UV and gamma irradiations are presented. Possibility of gamma-induced sensibilization process in Er^{3+} doped crystals is discussed. Positive result for non-pre-annealed gamma-irradiated rods of Er^{3+}:YAG crystal was stated.
12
Content available remote

Possibility of Gamma-Induced Sensibilization Process in Rare-Earth Doped Yag Crystals

80%
Kaczmarek S., Matkovskii A., Mierczyk Z., Kopczyński K., Sugak D., Durygin A., Frukacz Z.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 2
285-293
EN
The influence of gamma irradiation on optical and lasing properties of Nd:YAG, Er:YAG and CTH:YAG single crystals was studied. The increase in optical output was established for rods without thermal annealing. The possible mechanisms of radiation sensibilization are discussed.
13
Content available remote

Optical Spectra of Neodymium and Europium Tungstates and Molybdates

80%
Macalik L., Hanuza J., Legendziewicz J.
Acta Physica Polonica A
|
1993
|
vol. 84
|
issue 5
909-916
EN
Absorption and excitation spectra of lanthanides molybdates and tungstates were measured and analyzed. Probabilities of electronic transitions were analysed on the basis of the Judd-Ofelt theory. The significant differences of intensities were observed. Those differences could result from the symmetry changes, cooperative effects and electron-phonon interaction. The elucidation of intensities given by separate mechanisms needs further investigation.
14
Content available remote

Temperature Studies of Optical Birefringence in Molecular Liquids. I. Liquids with Linear Temperature Dependence

80%
Błaszczak Z., Doiari A.
Acta Physica Polonica A
|
1992
|
vol. 81
|
issue 4-5
475-484
EN
We report the first systematic study of the temperature dependence of optically induced birefringence in benzene, toluene, nitrobenzene, chlorobenzene, 2-bromoanisole, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 3-chlorobenzaldehyde and cinnamaldehyde. The optical Kerr constants, relative to benzene, are measured in a broad temperature range. Refractive indices and densities of the liquids for the temperatures studied were also determined. For the above liquids the T^{-1} temperature dependences of the optical Kerr constants have been found. From our measurements, the molar Kerr constants and the effective molecular anisotropies were calculated as functions of temperature. The mean values of the second-order optical hyperpolarizability have also been determined.
15
Content available remote

Optical Properties and Structure of Ln(NCS)(Hmpa)_{4}-(SCN)_{2}- HgCl(SCN)

70%
Gałdecka E., Gałdecki Z., Amirkhanov V., Kern K., Legendziewicz J.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 2
469-476
EN
Praseodymium, neodymium and europium complexes of the formula Ln(NCS)(Hmpa)_{4}-(SCN)_{2}-HgCl(SCN) were synthesised from non-aqueous solutions. The structure of neodymium complexes was determined by X-ray diffraction. The crystals of the title compounds crystallise in the space group Cc, where lanthanide ions are coordinated to seven ligand groups: four of Hmpa molecules and three SCN¯ ions. The compounds were characterised by IR, luminescence, excitation and absorption spectra at 6, 77, and 298 K. Probabilities of electronic transitions for Pr^{3+} ion were examined at 6 K and at room temperatures. Vibronic components were observed and analysed on the basis of IR and Raman data. Asymmetric arrangement of Ln ions was found from X-ray analysis and its influence on optical properties of active centre was discussed.
16
Content available remote

Structure and Spectroscopy of Selected Lanthanide Compounds with Coordination Number from 9 to 6

70%
Legendziewicz J.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 1
127-142
EN
The lecture deals with a group of lanthanide compounds in which some structural factors influence, in a special way, spectroscopic properties of the systems under investigation. The following systems were chosen: three with polymeric structure, two of the dimer type, one a pseudo-dimer system with coordination number (C.N.) = 7, and an octahedral compound of LnL_{6} type. The crystal structures of the systems under consideration will be shown, their absorption and excitation spectra will be presented and confronted with X-ray data. Radiative and nonradiative processes will be considered and the role of cooperative interactions analyzed. Some aspects of dynamics in solids will be done, too.
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