共查询到20条相似文献,搜索用时 31 毫秒
1.
A. P. Voitovich V. S. Kalinov Yu. V. Loiko N. N. Naumenko L. P. Runets A. P. Stupak 《Journal of Applied Spectroscopy》2008,75(1):104-113
We have shown that in spatial structures based on color centers created by electrons in a lithium fluoride crystal, the distances
between centers reach 1.6 nm and 3.6 nm for F1 and F2 centers respectively. This suggests considerable potential opportunities for using electron technology to form structures
in the crystals with spatial resolution of such an order of magnitude. We measured the decrease in fluorine content on the
irradiated surface of the crystal. We found the concentrations of F1, F2, F3+, F3(R2), and F4(N1) centers. We established that the specific characteristics of color center formation by electrons leads to an increase in
the efficiency of creation of F3 and F4 centers. We determined the decrease in the average luminescence lifetimes of F2 and F3+ centers as a result of concentration quenching. We observed distortion of the luminescence contour for F2 centers as a result of absorption of its short-wavelength portion by other centers and emission of radiation by the latter
in its long-wavelength portion.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 1, pp. 102–110, January–February, 2008. 相似文献
2.
V. S. Kortov I. A. Vainshtein A. S. Vokhmintsev N. V. Gavrilov 《Journal of Applied Spectroscopy》2008,75(3):452-455
We have studied the effect of bombardment by Cu+ and Ti+ ions with energy 30 keV on the optical absorption and luminescence of F centers in oxygen-deficient aluminum oxide. We have
shown that in the induced optical absorption spectra there are six components of gaussian shape, which can be assigned to
absorption bands of F+, F2, and F2+ centers. We have established that bombardment of the samples by ion beams has a weak effect on the thermoluminescence parameters
in the 3.0 eV and 2.4 eV bands, while in the 3.8 eV luminescence band for F+ centers, the thermoluminescent response increases considerably.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 422–424, May–June, 2008. 相似文献
3.
A. P. Voitovich V. S. Kalinov N. N. Naumenko A. P. Stupak 《Journal of Applied Spectroscopy》2006,73(6):866-873
For radiation-induced intrinsic color centers, we show that the concentrations of identical centers and the concentration
ratios of different centers are quite different in the near-surface layer and within the interior volume of a lithium fluoride
crystal. We have established that these differences also depend on the sign of the difference between the temperature at which
the crystal was irradiated with γ photons and the vacancy mobility temperature. We provide an interpretation for the results
obtained, based on the structural features of the near-surface layer and the concentration ratio of vacancies and electrons
in the layer, serving as the starting components for color center formation. We found that the concentrations of centers change
over the course of a few days by tens of percent in the layer “emerging” from the interior onto the surface as a result of
cleavage of the crystal. We measured the luminescence lifetimes of F3 (R2) and F4 centers: 6.6 nsec and 11.7 nsec.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 775–781, November–December, 2006. 相似文献
4.
We investigate the spectra of the x-ray radiation-induced absorption of SrCl2−Ce crystals over the spectral range 345–830 nm and their temperature transformations in the interval from 77 to 450 K. We
found that radiative color centers are characterized by a complex spectrum of induced absorption that contains wide bands
of photochromic PC (750, 519, 378 nm) and PC+ (620, 446, 340 nm) centers and quasi-linear bands of Ce2+ centers. The most significant thermal transformations of radiative color centers occur in the vicinity of the thermostimulated
luminescence peak of 394 K, at which the holes of the PC+ centers recombine with the electrons of the Ce2+ centers.
Ivan Franko L’vov State University, 8, Kirilla i Mefodiya St., L’vov 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 4, pp. 545–547, July–August, 1997. 相似文献
5.
We have studied the thermoluminescence curves in the 420 nm band (F centers) and the 330 nm band (F+ centers) within the temperature range of the dosimetric peak (Tmax = 450 K) in anion-deficient aluminum oxide crystals. Assuming general-order kinetics, we have analyzed the thermoluminescence
decay curves on the rising and falling sides of the dosimetric peak, in samples with different degrees of deep trap filling.
We have established differences in the order of the kinetics within different temperature ranges of the dosimetric peak.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 187–190, March–April, 2006. 相似文献
6.
Yu. V. Zorenko R. M. Turchak T. I. Voznyak Yu. B. Mamai 《Journal of Applied Spectroscopy》2006,73(3):406-410
We have used the Bridgman method to grow CsBr:Eu2+ single crystals, adding an activator to the mix in the form of Eu2O3 in amounts of 0.0125, 0.0250, and 0.0500 mole %. At T = 300 K, we studied the absorption spectra, the photoluminescence (PL)
spectra, and the photostimulated luminescence (PSL) spectra of the grown crystals. We have established that the structure
of the photoluminescence and photostimulated luminescence centers in crystals grown from the CsBr:Eu2O3 mix includes isolated dipole centers Eu2+-VCs, emitting in bands with maxima at 432 nm and 455 nm respectively, and in crystals grown at activator concentrations of 0.025
and 0.050 mole % they also include aggregate centers (AC) based on CsEuBr3 nanocrystals with emission bands at 515 m and 523 nm. We have shown that the maximum concentration of aggregate centers of
the CsEuBr3 nanocrystal type in CsBr:Eu2+ crystals is achieved for an activator content in the mix within the range 0.01–0.05 mole %.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 359–362, May–June, 2006. 相似文献
7.
A. P. Voitovich V. S. Kalinov G. Baldacchini R. M. Montereali M. Cremona 《Journal of Applied Spectroscopy》1998,65(5):778-795
Results of investigations of radiative F
3
+
-color centers in lithium fluoride obtained by the methods of one- and two-photon absorption, polarization spectroscopy, and
luminescence in singlet, triplet and triplet-singlet channels are reported. The scheme of energy levels of the F
3
+
-center is revised. The probabilities of singlet-triplet conversion and the rates of depletion of the lower triplet state
in the range of 80–350 K are presented. Recommendations are given on the technology of radiative LiF coloration that provide
an increase in the F
3
+
-center concentration and a decrease in the concentration of some other centers that prevent lasing on the LiF:F
3
+
active medium from being obtained. The phototransformations of color centers in LiF are analyzed. The parameters of lasers
with LiF:F
3
+
active media that provide generation of radiation tunable in the green region of the spectrum are considered. Based on spectroscopic
data the maximum attainable time characteristics of such lasers are discussed. The prospects for further investigations of
LiF:F
3
+
lasers are outlined in brief.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 745–760, September–October, 1998. 相似文献
8.
M. U. Belyi V. N. Bindyukevich A. S. Kolesnik B. A. Okhrimenko V. P. Yashchuk 《Journal of Applied Spectroscopy》2000,67(1):95-100
Comprehensive investigations of luminescence, excitation, and absorption spectra as well as of the luminescence kinetics of
a frozen LiCl-Tl+ solution are carried out. It is established that the luminescence spectrum consists of four components. One component is
caused by luminescence of the matrix and the remainder by luminescence of one luminescence center, namely, by the saturated
complex of thallium TlCl2(H2O)Cl4. The absorption spectrum consists of three components. Their parameters have been evaluated. Each component of the luminescence
spectrum is excited in several components of the absorption spectrum. It is found that the luminescence spectrum components
and their intrinsic absorption bands are located differently on the frequency axis. These data are similar to those obtained
for other activated solutions of electrolytes.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 1, pp. 75–78, January–February, 2000. 相似文献
9.
A new phenomenon — intense luminescence of noncolored lithium fluoride (LiF) crystals excited by an electrodeless pulsed microwave
discharge at the prebreakdown stage of development — is observed. This luminescence consists of the luminescence of short-lived
aggregate F2 and F
3
+
color centers at room temperature. It is shown that the density of short-lived color centers induced in the surface layer
of LiF crystals by a microsecond microwave discharge reaches values of ∼1019−1020 cm−3.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 3, 163–167 (10 August 1997) 相似文献
10.
Yu. V. Zorenko R. M. Turchak T. I. Voznyak A. P. Luchechko 《Journal of Applied Spectroscopy》2006,73(2):211-215
By liquid-phase epitaxy from an aqueous alcoholic solution, we have obtained films of the well-known storage phospor CsBr:Eu,
and we have studied their cathodoluminescence and photoluminescence (PL) spectra compared with the undoped CsBr films. We
have established that the structure of the photoluminescence centers of the CsBr:Eu films when excited by laser radiation
in the absorption band of the Eu2+ ions (λ = 337 nm) includes Eu2+-VCs isolated dipole centers and CsEuBr3 aggregate centers, and also luminescence centers based on inclusions of hydroxyl group OH− with the corresponding emission bands in the 440 nm, 520 nm, and 600 nm regions. We have studied the dependence of the spectra
and the intensity of the photoluminescence for CsBr:Eu films on annealing temperature in air at 423–483 K, compared with analogous
dependences for CsBr:Eu single crystals obtained from the melt. We have shown that annealing the films at T = 423–463 K leads
to rapid formation of CsEuBr3 aggregate luminescence centers, while for T > 473 K thermal degradation of these centers occurs.
We conclude that the observed differences between the photoluminescence spectra of CsBr:Eu films and CsBr:Eu single crystals
may be due to additional doping of the films with OH− ions.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 191–194, March–April, 2006. 相似文献
11.
12.
The thermoluminescence of single crystals of corundum containing anion defects following x-ray and laser excitation is investigated.
Its features in the luminescence bands of F, F+, and Cr3+ centers are studied. Synchronous measurements of the thermoluminescence and thermally stimulated exoelectron emission are
performed by the fractional glow technique following x-ray and laser excitation of the samples. It follows from the results
obtained that several traps are active in the temperature range of the principal dosimetric peak (400–500 K). The spectral
sensitivity curve contains maxima corresponding to absorption bands of F, F+, and Al
i
+
centers. A possible mechanism for the recombination luminescence of F centers is discussed. It is found that the material
exhibits high sensitivity to small doses of ultraviolet laser radiation.
Zh. Tekh. Fiz. 67, 72–76 (July 1997) 相似文献
13.
A. P. Voitovich M. V. Voitikova V. S. Kalinov E. F. Martynovich A. N. Novikov L. P. Runets A. P. Stupak R. M. Montereali G. Baldacchini 《Journal of Applied Spectroscopy》2011,77(6):857-868
Lithium fluoride crystals were irradiated by different doses of gamma photons at a temperature of 77 K. We measured the aggregation
kinetics for the color centers with different annealing temperatures above the temperature of anion vacancy mobility. We show
that the lifetimes of the vacancies decrease while the lifetimes of the F2+ F_2^{+} centers increase as the irradiation dose increases. We explain these types of dependences based on the aggregation processes
for color centers in the post-radiation period. We determine the time constants and energies (analogous to activation energies
in the Arrhenius equation) for the various processes involving rise and fall in the concentration of aggregate color centers.
Based on the experimental data obtained, we have established the processes forming F
2 and F3+ F_3^{+} centers in the post-radiation period. The F
2 centers are formed when vacancies νa add to F1- F_1^{-} centers. Vacancies arising during irradiation of the crystal participate in their creation in the first fast stage. In the
long final stage, vacancies are used which appear in the post-radiation period on occurrence of the reaction F2+ F_2^{+} + H → νa + fluoride ion at the lattice site, where H is an interstitial fluorine atom. The F3+ F_3^{+} centers are formed both by merging F2+ F_2^{+} and F
1 centers and as a result of addition of vacancies to F
2 centers. In this case, vacancies are used that are generated not only during irradiation of the crystal but also in the post-radiation
period. The rise in the concentration of F3+ F_3^{+} centers occurs faster than the rise in the concentration of F
2 centers. 相似文献
14.
We have studied the spectral luminescence properties of mixed-ligand complexes of Eu(III) ions with tetracyclines and hydrogen
peroxide. We have established that incorporation of hydrogen peroxide into the inner sphere of these complexes leads to a
significant increase (by a factor of 10–25) in the intensity of luminescence of the Eu(III) ions, redistribution of the intensities
of the 5D0 → 7Fj transitions, in particular to an anomalous increase in the intensity of the band for the forbidden transition 5D0 → 7F0.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 3, pp. 310–314, May–June, 2007. 相似文献
15.
Irina Kudryavtseva Aleksandr Lushchik Aarne Maaroos Zhannur Azmaganbetova Turlybek Nurakhmetov Zhussupbek Salikhoja 《Central European Journal of Physics》2012,10(4):995-1001
A comparative study of the excitation of luminescence by VUV radiation as well as of thermally and photostimulated luminescence
has been carried out for CaSO4:Tb3+ and CaSO4:Gd3+ phosphors, where Na+ or F− ions are used for charge compensation. The distinction in hole processes for the phosphors with Na+ or F− compensators is determined by the differing thermal stability of the holes localized at/near Tb3+Na+ and Gd3+Na+ (up to 100–160 K) or at/near Tb3+F−
V
Ca and Gd3+F−
V
Ca centers involving also a cation vacancy (up to 400–550 K). Tunnel luminescence in the pairs of localized electrons and holes
nearby Tb3+ or Gd3+ has been detected. The mechanisms of electron-hole, hole-electron and tunnel recombination luminescence as well as a subsequent
released energy transfer to RE3+ ions are considered. 相似文献
16.
V. I. Tsaryuk K. P. Zhuravlev V. F. Zolin V. A. Kudryashova J. Legendziewicz R. Szostak 《Journal of Applied Spectroscopy》2007,74(1):51-59
We discuss the possibility of optimizing the brightness of luminescence for phenylcarboxylates, naphthylcarboxylates, and
indolylcarboxylates of europium and terbium and their adducts with 1,10-phenanthroline and 2,2′-bipyridine by modifying the
ligands. We have studied the efficiency of luminescence and luminescence excitation. We consider the effect of blocking energy
transfer from the ligands to the Eu3+ and Tb3+ ions by methylene (-CH2-) bridges dividing the π-electron system of the ligands into two parts and by the electronacceptor nitro group (-NO2). We have analyzed the pathways for transfer and degradation of the excitation energy at 77 K and 300 K. From the phosphorescence
spectra of gadolinium salts, we have determined the energies of the lowest excited triplet states of the ligands. We consider
the effect of the relative positions of the triplet levels of the ligands and the excited levels of the Eu3+ and Tb3+ ions on the luminescence efficiency. We found channels for dissipation of the excitation energy via the ππ* and nπ* states
of the aromatic system of the carboxylate and the NO2 group.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 48–54, January–February, 2007. 相似文献
17.
I. V. Berezovskaya N. P. Efryushina A. S. Voloshinovskii G. B. Striganyuk P. V. Pir V. P. Dotsenko 《Journal of Applied Spectroscopy》2006,73(6):861-865
We have studied the luminescent properties of Eu2+/3+ and Yb2+ ions in strontium hexaborate SrB6O10 for excitation in the 120–400 nm region. The luminescence spectra of Ln2+ ions in SrB6O10 consist of overlapping bands in the 370–520 nm region, due to 5d → 4f transitions at several nonequivalent centers. In the
excitation spectra, besides the bands associated with 4f → 5d transitions in the Ln2+ ions, we also observe a band in the 135–160 nm region due to the transitions O(2p) → B(2s,2p) within the borate anions. The
luminescence of the Eu3+ ions is excited most efficiently in the region of the Eu3+ charge transfer band (λmax = 226 nm). The results obtained are compared with data for Ln in other strontium borates.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 770–774, November–December, 2006. 相似文献
18.
R. R. Bagautdinov S. O. Stepanova V. I. Korotkov B. N. Korvatovskii V. V. Akulinichev 《Journal of Applied Spectroscopy》1999,66(4):617-621
The luminescence and excitation spectra and kinetic characteristics of the luminescence of the adsorbates of magnesium phthalocyanine
(MgPhc) on SiO2 and the effect on them of surface hydration and finely dispersed platinum are studied. It is found that a structure that
improves hydration of the adsorbent surface appears on the platinized surface in the luminescence and excitation spectra.
It is assumed that the spectral structure is due to the complexes of MgPhc formed with water molecules, the hydroxyl cover
of the surface, and the surface centers of SiO2 modified by a Pt-catalyst.
Reported at the VIIIth International Conference on Spectroscopy of Porphyrins and Their Analogs, Minsk, September 22–26, 1998.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 66, No. 4, pp. 552–555, July–August, 1999. 相似文献
19.
V. Yu. Ivanov V. A. Pustovarov A. V. Kruzhalov D. S. Tausenev E. I. Zinin 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(4):671-674
The results of comparative luminescence investigation of natural and synthetic BeO crystals are presented. Time-resolved luminescence
(2.5–8 eV) and luminescence excitation spectra, and the kinetics of glow decay were measured using ultraviolet-vacuum-ultraviolet
(VUV) synchrotron radiation (5–22 eV) or x-radiation (50–620 eV or 3–62 keV) ranges. X-ray and thermostimulated luminescence
of natural BeO crystals were compared to the glow of additively colored synthetic crystals. The characteristic luminescence
of F and F
+ centers was found in natural crystals. In synthetic crystals similar luminescence is observed only after additive or radiation
coloration by virtue of the creation of F
− and F
+ centers on anion vacancies. The defects found in the crystal lattice of a natural BeO crystal testify to the degree of mineral
metamictization of the given deposit. 相似文献
20.
M. Pedroza-Montero B. Castañteda R. Meléndrez V. Chernov M. Barboza-Flores 《辐射效应与固体损伤》2013,168(3-4):319-324
Abstract We present thermoluminescence (TL) glow curves and optical stimulated luminescence (OSL) response from both KCl:Eu2+ crystals irradiated with soft X-rays (20 KV, 80 μA) and ultraviolet light (230 nm). Two situations take place. First, we observed that for long time F-light bleaching (560 nm) the typical TL glow curve of X-rays irradiated KCl:Eu2+ resembles the TL glow curve of UV-irradiated samples. Second, along with OSL measurements, we have performed a thermal bleaching and we have addressed F and Fz participation in OSL. These results provide us a supportable correlation between F and Fz as responsible centers for OSL and TL processes. 相似文献