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1

Implications of Invalid Conversions between Crystal-Field Parameters and Zero-Field Splitting Ones Used in Superposition Model

100%

Rudowicz C., Karbowiak M.

Acta Physica Polonica A

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2014

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vol. 125

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issue 5

1215-1219

EN

The methodology used in recent study of the zero-field splitting parameters of Cr^{3+} ions at various orthorhombic symmetry sites in LiKSO_4 by Pandey and Kripal is critically commented on. We argue that the crystal field parameters, B_{kq}, in the Wybourne notation, which were calculated using the superposition model for Cr^{3+} ions in LiKSO_4, may only be converted into the crystal field parameters in the Stevens notation. Regrettably, the authors have also converted the latter parameters supposedly into the zero-field splitting parameters D and E in the conventional notation. Such direct conversions are fundamentally incorrect and constitute factual invalid usage of the conversion relations between the crystal field (ligand field) parameters and the zero-field splitting ones. The cases of an implied usage of the invalid conversion relations between the crystal field parameters and the zero-field splitting parameters occurring in recent literature are also outlined. Pandey and Kripal have found the zero-field splitting parameters theoretically evaluated in this way to be in good agreement with the experimental values. However, the faulty methodology renders the conclusion that Cr^{3+} ions enter into the LiKSO_4 lattice at the substitutional K^{+} sites unjustified. Several other conceptual problems arising from misinterpretations of the crucial notions identified therein are also discussed and clarified.

2

Analysis of Emission and Vibronic Transitions in Uranium(3+) Doped Cs_{2}LiYCl_{6} Single Crystals

81%

Karbowiak M., Simoni E., Drożdżyński J., Hubert S.

Acta Physica Polonica A

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1996

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vol. 90

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issue 2

367-370

EN

Uranium(3+) doped single crystals of Cs_{2}LiYCl_{6} with a 0.3 and 2.0% U^{3+} concentration have been obtained by the Bridgman-Stockbarger method. Luminescence spectra of the crystals were recorded at 27 and 15 K, respectively. The emission bands observed in the visible and near infrared regions have been assigned to transitions from the ^{4}I_{11/2}, ^{4}F_{3/2}, and ^{4}G_{7/2} levels to the ^{4}I_{9/2} ground level.

3

Luminescence and Excitation Spectra of U^{3+} doped RbY_{2}Cl_{7} Single Crystals

71%

Karbowiak M., Murdoch K., Drożdżyński J., Edelstein N., Hubert S.

Acta Physica Polonica A

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1996

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vol. 90

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issue 2

371-376

EN

Uranium(3+) doped single crystals of RbY_{2}Cl_{7} with a uranium concentration of 0.05% and 0.2% were grown by the Bridgman-Stockbarger method using RbU_{2}Cl_{7} as the doping substance. Polished plates of ca. 5 mm in diameter were used for measurements of luminescence and excitation spectra. Since the U^{3+} ions occupy two somewhat different site symmetries, a splitting of all observed f-f bands was observed. The analysis of the spectra enabled definitively an assignment of 22 crystal field bands for both site symmetries as well as the total crystal field splitting of the ground level, equal to 473 cm^{-1} and 567 cm^{-1} for the first and second site symmetry, respectively.

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3 Acta Physica Polonica A

1 2014

2 1996

3 Karbowiak M.

2 Drożdżyński J.

2 Hubert S.

1 Edelstein N.

1 Murdoch K.

1 Rudowicz C.

1 Simoni E.

Implications of Invalid Conversions between Crystal-Field Parameters and Zero-Field Splitting Ones Used in Superposition Model

Analysis of Emission and Vibronic Transitions in Uranium(3+) Doped Cs_{2}LiYCl_{6} Single Crystals

Luminescence and Excitation Spectra of U^{3+} doped RbY_{2}Cl_{7} Single Crystals