�ber die Fluoreszenz der zweiwertigen Seltenen Erden

Przibram, Karl

doi:10.1007/bf01339307

Cited by 13 publications

(4 citation statements)

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“…The sharp lines and the luminescence emission in the 200 to 300 nm region are not present in thermoluminescence [16]; this emission which is present in X-ray luminescence decreases in intensity with rise in temperature. These seem t o have their origin in the electron hole recombination a t the trivalent rare earth impurity ion sites for sharp lines [17] and a t the lattice and divalent impurity ion sites for the broad bands [18] in the region of 200 to 300 nm. The large intensities in this region are due to the availability of a large number of recombination sites and centres.…”

Section: Fluorescence Spectramentioning

confidence: 99%

On the Colour Centres and X‐Ray Luminescence of Calcium Fluoride Crystals

Ratnam

1966

Physica Status Solidi (b)

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A study is made of differences in the colouration spectrum of calcium fluoride crystals obtained by X-ray irradiation a t different temperatures and by electrolysis. The change6 occurring in the X-ray luminescence spectrum due to the use of different irradiation temperatures are also considered. It is shown that the a-and P-bands, usually only observed in additive and electrolytic colouration, can also be produced by X-ray irradiation if the irradiation temperature is between 180 and 250 "C. The formation of the a-band (the F-band of this system) is difficult t o detect a t lower irradiation temperatures because of 1. the small number of free negative ion vacancies a t these temperatures and 2. the low oscillator strength associated with this band. The changes observed in the X-ray luminescence spectrum for different irradiation temperatures are explained and the associated electronic processes are discussed briefly.Unterschiede im Verfkrbungsspektrum von Kalziumfluoridkristallen werden untersucht. Die Verfiirbung erfolgt durch Rontgenbestrahlung und durch Elektrolyse, wobei die Unterschiede im Lumineszenzspektrom durch Rontgenbestrahlung bei verschiedenen Temperaturen ebenfalls berucksichtigt werden. E s wird gezeigt, da13 die a-und P-Banden, die gewohnlich nur bei additiver und elektrolytischer Verfiirbung beobachtet werden, auch durch Rontgenbestrahlung erzeugt werden, wenn die Bestrahlungstemperatur zwischen 180 und 250 "C liegt. Die Bildung der a-Bande (die F-Bande dieses Systems) ist bei niedrigeren Bestrahlungstemperaturen schwierig nachzuweisen, wegen 1. der geringen Anzahl von freien negativen Ionenliicken bei diesen Temperaturen und 2. der niedrigen mit dieser Bande verbundenen Oszillatorenstarke. Die Unterschiede im Lumineszenzspektrum fur verschiedene Bestrahlungstemperaturen werden erklart und die damit verbundenen elektronischen Prozesse kurz diskutiert.

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Section: Fluorescence Spectramentioning

confidence: 99%

On the Colour Centres and X‐Ray Luminescence of Calcium Fluoride Crystals

Ratnam

1966

Physica Status Solidi (b)

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“…Eu +3 in pure europium(III) compounds has line emission similar to that of Eu incorporated into the "normal" oxide phosphors (6). Recently, it has been shown that divalent Eu salts, have band emission (23,24). Thus it appears that line emission is characteristic of Eu +s and band emission of Eu +2.…”

Section: September 1955mentioning

confidence: 99%

Oxidation States of Europium in the Alkaline Earth Oxide and Sulfide Phosphors

Jaffe

Banks²

1955

J. Electrochem. Soc.

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Emission and absorption spectra of the alkaline earth sulfides activated with europium and fired in a neutral atmosphere have been re-investigated. The emission and absorption spectra of the alkaline earth oxides, also activated with Eu, and fired in a neutral or a reducing atmosphere have been obtained. The sulfides show both band emission and band absorption, as does SrO fired in hydrogen. The other hydrogen-fired oxides have band absorption, except for MgO, and give either mixed band and line emission or only line emission. The nitrogen=fired oxides, except MgO, give line emission and little, if any, selective absorption. MgO emits a broad line spectrum for both the nitrogen-and hydrogen-fired samples and shows no absorption peaks. Emission and absorption spectra have been correlated with the oxidation state of the activator in the several phosphors, the line emissions being associated with the presence of Eu +a and the band emissions with Eu +2.

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“…from 3d6 iron(II) to 3d0 titanium(IV) in blue sapphire Al2-2xΤixO 3 or black ilmenite FeΤiO3, or from 4d10 silver(I) to permanganate, 5d group complexes OsBr6-2 or IrCl6-2 [18]. It is worth noting that frequent minerals and rocks, which would be white in their iron-free "idealized" formula (as Na, Mg, Al, K, Ca silicates) usually are grey to almost black due to simultaneous presence of iron(II) and iron(III) known from greenish black Fe(OΗ)2+x" and prussian blue KFe(CN) 6 FuII As first observed in coloured, luminescent fluorites Ca1-xLnxF2 by Przibram [20], lanthanides(II) such as dark green Sm(ΙΙ), pale yellow Eu(II) and Yb(II) show strong absorption bands. In analogy to the conditions for Laporte-allowed transitions in atomic spectra, it is agreed today that the excited state belongs to 4 f 4-1 5d, much like strong absorption bands in the visible of grey uranium(III) acquoions, their raspberry-red chloride complexes [21] and U(III) in crystals show the excited configuration 5 f 2 6d.…”

Section: Introductionmentioning

confidence: 98%

Rationalization of Spectra of Rare Earths in Condensed Matter

Reisfeld

Jørgensen

1993

Acta Phys. Pol. A

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The parametrized models are compared with counter-intuitive consequences of the non-relativistic Schrödinger treatment. For both 4 f q, 5f q and d9 systems in condensed matter, the energy levels must be strongly influenced by correlation effects. The parametrization of intensities is conceptually very different for f' and d9 compounds. The bandwidths of absorption and luminescence are discussed and related to the Born-Oppenheimer factorization.

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�ber die Fluoreszenz der zweiwertigen Seltenen Erden

Cited by 13 publications

References 0 publications

On the Colour Centres and X‐Ray Luminescence of Calcium Fluoride Crystals

On the Colour Centres and X‐Ray Luminescence of Calcium Fluoride Crystals

Oxidation States of Europium in the Alkaline Earth Oxide and Sulfide Phosphors

Rationalization of Spectra of Rare Earths in Condensed Matter

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