Optical absorption and luminescence investigations of the precipitated phases of Eu 2+ in NaCl and KCl single crystals
Optical absorption and luminescence investigations of the precipitated phases of Eu 2+ in NaCl and KCl single crystals
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NaCl和KCl单晶中Eu 2 沉淀相的光吸收和发光研究
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发表时间：
1980
期刊：
影响因子：
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通讯作者：
F. López
中科院分区：
文献类型：
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作者：
F. López
本文详细研究了二价铕在NaCl和KCl单晶中析出相的光学吸收和发光光谱。对于NaCl-Eu${mathrm{Cl}}_{2}$体系，在室温下保存6年的晶体中，未经任何热处理，观察到在410、439和485 nm处有三个荧光带。这些晶体对应的光吸收光谱在260和349nm处有两个宽频带，其立方晶体场分裂为10Dq=9809 ${mathm {cm}}^{ensuremath{-}1}$。在600ifmmode^ cirelexdegreefi {}C淬火后，晶体仅在427 nm处观察到一个发射带，相应的光吸收光谱也由两个宽频带组成，但现在在240和347 nm处达到峰值，10Dq分裂为12 849 ${mathm {cm}}^{ensuremath{-}1}$。在410 nm处的发射峰与稳定的二卤化物相Eu${mathm {Cl}}_{2}$有关，而在439和485 nm处的发射峰分别与平行于基体晶格{111}和{310}面的亚稳沉淀Eu${mathm {Cl}}_{2}$类似板带有关。对于KCl-Eu${mathrm{Cl}}_{2}$体系，未经任何热处理，在室温下保存5年的晶体中，只观察到一个在427 nm处的发射峰。这些老化良好的晶体对应的光吸收光谱由两个宽波段组成，峰值在244和349nm处，10Dq值为12 331 ${mathm {cm}}^{ensuremath{-}1}$。猝灭后，样品在419 nm处有一个发射带，其光吸收光谱与猝灭前非常相似，但其10Dq分裂较小（11 997 ${mathm {cm}}^{ensuremath{-}1}$）。在这种情况下，在老化良好的晶体中观察到的427 nm处的波段峰值初步与氯化钾宿主中二价铕的亚稳铃木相有关。本文还报道了${mathm {Eu}}^{2+}$在NaCl和KCl中不同析出相的吸收、激发和发射光谱随退火温度的变化。
A detailed study of the optical absorption and luminescence spectra associated with the precipitated phases of divalent europium in NaCl and KCl single crystals is reported. For the system NaCl-Eu${mathrm{Cl}}_{2}$, three fluorescence bands peaking at 410, 439, and 485 nm were observed in crystals which were stored for six years at room temperature, without any previous heat treatment. The corresponding optical-absorption spectrum of these crystals consists of two broad bands peaking at 260 and 349 nm with a cubic crystalline field splitting 10Dq=9809 ${mathrm{cm}}^{ensuremath{-}1}$. After quenching the crystals from 600ifmmode^circelse extdegreefi{}C, only one emission band peaking at 427 nm was observed and the corresponding optical-absorption spectrum consists also of two broad bands but now peaking at 240 and 347 nm with a 10Dq splitting of 12 849 ${mathrm{cm}}^{ensuremath{-}1}$. The emission band at 410 nm in the well-aged crystals was associated with the stable dihalide phase Eu${mathrm{Cl}}_{2}$, while those peaking at 439 and 485 nm were ascribed to the metastable precipitated Eu${mathrm{Cl}}_{2}$-like plate zones parallel to {111} and {310} planes of the matrix lattice, respectively. For the system KCl-Eu${mathrm{Cl}}_{2}$, only one emission band peaking at 427 nm was observed in crystals stored at room temperature for five years, without any previous heat treatment. The corresponding optical-absorption spectrum of these well-aged crystals consists of two broad bands peaking at 244 and 349 nm with a 10Dq value of 12 331 ${mathrm{cm}}^{ensuremath{-}1}$. After quenching the samples, an emission band at 419 nm was observed and the corresponding optical-absorption spectrum was very similar to that observed before the quenching, although its 10Dq splitting was smaller (11 997 ${mathrm{cm}}^{ensuremath{-}1}$). In this case, the band peaking at 427 nm, observed in the well-aged crystals, has been tentatively associated with the metastable Suzuki phase of divalent europium in the potassium chloride host. The change in the absorption, excitation, and emission spectra associated with the different precipitated phases of ${mathrm{Eu}}^{2+}$ in NaCl and KCl as a function of the annealing temperature is also reported.