Steady-State Luminescence Spectroscopy

It was established by steady-state luminescence spectroscopy that minerals of Mn, such as rhodonite, rhodochrosite, helvine, triplite, Mn-apatite, Mn-milarite and others, show dark red luminescence, mainly at 77 K, which is uncommon to impurity Mn ". The excitation center proved to be regular Mn ", while the emission center is Mn ", situated near some lattice defect (Gorobets et al. 1978 Gaft et al. 1981). 

The lines of Sm + connected with several types of centers are well studied in fluorite by steady-state luminescence spectroscopy (Tarashchan 1978 Krasilschikova et al. 1986). In time-resolved spectra it is mostly prominent after long delay times and is mainly characterized by the Hnes at 562,595 and 651 nm (Fig. 4.10d). 

The possible luminescence of Eu " in scheelite is a very interesting problem. It was not detected by steady-state luminescence spectroscopy. The possible reason is that the very strong intrinsic luminescence of scheehte is situated in the same spectral range, which covers the weaker emission of Eu ". We tried to solve this problem by the time-resolved method using different decay times for intrinsic and Eu bands. Time-resolved spectroscopy... 

Characteristic bands of Mn + well studied by steady-state luminescent spectroscopy (Tarashchan 1978 Gorobets and Rogojine 2001) have been found in time-resolved luminescence spectra of calcite (Fig. 4.14a), fluorite (Fig. 4.10d), datolite (Fig. 4.16d), wollastonite (two bands at 555 and 603 nm Fig. 4.42a,c), and spodumen (Fig. 4.61a). 

Nickel, in a very useful paper, has discussed the elimination of polarization bias effects from the measurement of luminescence properties and transient absorption in isotropic solutions. The theoretical treatment is fully developed and recommendations are given for making reliable observations under a variety of experimental conditions are detailed. Determination of quantitative data from steady state luminescence spectroscopy is by no means as straightforward as many workers assume this work very convincingly demonstrates otherwise. 

Steady-State Luminescence Spectroscopy 3.2.1 Experimental Apparatus... 

Shortite was studied by steady-state luminescence spectroscopy and luminescence of trivalent REE, such as Gd, Dy, Sm and Tb was found (Gorobets and Rogojine 2001). Excitation by CW laser with 532 and 780 nm revealed narrow luminescence lines possibly belonging to Nd " and two luminescence bands peaking at 650 and 705 nm (Fig. 4.54). Additional study is needed to ascribe those emission centers including their decay times and excitation spectra. 

Burbankite was studied by steady-state luminescence spectroscopy and luminescence of trivalent REE, such as Dy, Sm and Nd, was found (Gorobets and Rogojine 2001). 

It is a rare lead silicate which was not studied by steady-state luminescence spectroscopy. Laser-induced time-resolved technique (Figs. 4.64 and 4.65) enables to detect two types of Pb ", two types of Mn " and Ce emission centers (Gaft et al. 2013a). 

Gahhite was studied by steady-state luminescence spectroscopy and Mn " luminescence was found peaking at approximately 515 nm (Goirobets and Rogojine 2001). Excitation by CW laser with 532 nm revealed several two additional bands peaking at 647 and 732 nm and narrow lines peaking at 676, 686 and 698 nm (Fig. 4.86). Narrow lines evidently may be ascribed to Cr " while the broad bands need further study. 

Smithsonite has been studied by steady-state luminescence spectroscopy and evi-... 

Trivalent europium is an excellent ionic probe for materials and its luminescence properties are extensively studied. Eu is one of the mostly informative elements in mineralogy, especially when the ratio Eu /Eu may be assessed. Both oxidation states are luminescent, but the lines of Eu in minerals are usually very weak and concealed by other centers. By steady state luminescence spectroscopy its luminescence has been confidently detected only in scheelite and anhydrite (Tarashchan 1978 Gorobets and Rogojine 2001). 

The luminescence of many titanium minerals was studied by steady-state luminescence spectroscopy and it was proposed that blue luminescence bands mutual for these minerals is connected with TiOe complex luminescence (Gaft et al. 1981a White 1990). Figure 4.82a presents spectral properties of the blue emission from benitoite at 300 K. Under short and middle-wave UV laser excitation, such as at 266 and 308 nm, respectively, an intensive broad blue emission band peaking at approximately 420 nm with half-width of 80 nm is detected. Spectra with different excitations, delays and gates revealed that this band consists of only one... 

The book deals mainly with theoretical approach, experimental results and their interpretation of laser-induced time-resolved spectroscopy of minerals in the wide spectral range from 250 to 2000 nm, which enables to reveal new luminescence previously hidden by more intensive centers. Artificial activation by potential luminescence centers has been accomplished in many cases, which makes the sure identification possible. The mostly striking example is mineral apatite, which has been extremely well studied by many scientists using practically all known varieties of steady-state luminescence spectroscopy photoluminescence with lamp and laser excitations. X-ray excited luminescence, cathodoluminescence, ionolumi-nescence and thermoluminescence. Nevertheless, time-resolved spectroscopy revealed that approximately 50 % of luminescence information remained hidden. The mostly important new information is connected with luminescence of trivalent... 

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