Verfärbung und Lumineszenz bei Korund

Ohne Zusammenfassung

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Auszug aus dem am 4. 11. 1954 auf der Konferenz über Einkristalle in Turnov vorgetragenen Referat.     

Die Exoelektronen- und Thermoelektronenemission bei einigen Halogeniden

Zusammenfassung Es wird Vergleich angestellt zwischen den experimentellen und theoretischen Thermoemissionskurven für den mono- und bimolekularen Proze bei Kristallen von NaCl und CaF₂, die die Farbzentren F enthalten. Rechnerisch wird der Einflu der Austrittsarbeit auf die Lage der Thermoemissionsmaxima und auf die Intensität der Thermoemission verfolgt. Die bei den Halogeniden erzielten Ergebnisse gaben die Möglichkeit, gewisse Schlüsse zu ziehen über den Mechanismus der Thermoelektronenemission bei Oxydkathoden.

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- NaCl u CaF₂, F. . , .

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Wir danken unseren Kollegen, insbesondere dem Kandidaten der phys. math. Wissenschaften J. Kanturek für die wertvollen Diskussionen und K. Listoová für die sorgfältige Durchführung der Versuche.     

The physical behaviour of copper in KCl crystal

Measurements of the absorption and dielectric losses on KCl crystals with high concentration of copper were performed at room and liquid nitrogen temperature. The exciton bands at 383 nm and 375 nm were found as in the case of similar NaCl-Cu samples. After the annealing the bands disappeared, the bands at 226 and 330 nm decreased and the tan-peak at 50 C increased. The interpretation is given on the basis of the existence of Cu-ion agglomerates and their disintegration in octohedral chlorocopper complexes after annealing.The authors wish to express their appreciation to their co-workers K. Dolealová and J. Matouová for careful execution of the experiments.     

Optische und elektrische Erscheinungen in kupferaktivierten Natriumchloridkristallen

NaCl crystals activated with copper were prepared either from the melt or from an aqueous solution. They were coloured either photochemically or additively. The absorption, luminescence and electron emission were then measured on such crystals. The experimental results show the cause of the different results obtained by different authors and what conclusions can be drawn for the elaboration of models of luminescent centres.     

Y-Absorptionsbande im bestrahlten LiF

The absorption measurements at a constant and uniformly increasing temperature and the thermostimulated electron emission and luminescence of with α-, cathode- andγ-rays irradiated LiF crystals were performed and the conditions of the formation of a new absorption band at about 500 nm investigated. It turned out that the band in α-irradiated samples is composed from two and inγ-irradiated from three bands. In this case the short-wave-length-band with the zero-phonon-line at 491 nm is very probably the well knownF ₃ ^t -band. The long-wave-length-band with the zero-phononline at 507 nm (theX band) is of unknown nature. TheY band lies at 494,3 nm (at 77 ?K) and its nature could consist in the colour centre agglomerates.     

Spectral composition of thermoluminescence of coloured NaCl crystals

The paper gives the experimental results of studying the spectral composition of thermoluminescence in the different maxima in photo-chemically coloured pure NaCl crystals or NaCl-crystals containing Cu in different concentrations.

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NaCl

NaCl .

     

Absorption bands of lead in mixed KCl + KBr crystals

The absorption spectra of mixed KCl + KBr crystals with lead added were measured. The main attention was devoted to A bands and their fine structure. Measurements were made at different temperatures. The results are discussed from the point of view of the existence of lead complexes in crystals of alkali halides.