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1.
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
2.
For an ensemble of different types of luminescence centers with overlapping absorption bands, with no restrictions on the
optical densities, we have obtained relations describing the luminescence excitation spectra for each type of center. We consider
transformations of the relations in some limiting cases. We suggest a procedure for using the equations obtained to determine
the characteristics of the luminescence centers. Some of these procedures have been experimentally implemented in study of
intrinsic radiation color centers in lithium fluoride crystals. We have determined the ratios of the luminescence quantum
yields for F2 and F3+ color centers, and we have observed that a major role is played by nonradiative transitions in deactivation of the first
excited singlet state of F3+ centers.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 75, No. 3, pp. 365–371, May–June, 2008. 相似文献
3.
I. Kh. Abdukadyrova 《Journal of Applied Spectroscopy》2006,73(4):557-561
IR spectroscopy has been used to study the process of structural damage and changes in some characteristics of fused silica
irradiated by fast neutrons over a very broad fluence range (1017–1021 cm−2). Features of the change in spectral characteristics of the bending and stretching vibrations of the bridge bonds have been
identified, and also a comparative analysis has been carried out with radiation-induced changes in a series of optical spectra
in the UV and visible regions, and structural parameters and other characteristics of wafers irradiated by different fluences.
A correspondence has been established between the features of the radiation-induced changes in the optical, luminescence,
and structural properties, and extremal points have been observed on the dose dependences. Based on the results obtained,
a mechanism of radiation-induced rearrangement of the silica structure is suggested.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 494–497, July–August, 2006. 相似文献
4.
A. I. Nepomnyashchikh A. A. Shalaev A. K. Subanakov A. S. Paklin N. S. Bobina A. S. Myasnikova R. Yu. Shendrik 《Optics and Spectroscopy》2011,111(3):411-414
LiF single crystals with copper impurity (0.0004–0.002%) have been grown by the Czochralski method and investigated. The luminescence,
excitation, and optical absorption spectra have been recorded. The luminescence spectrum contains a band at 450 nm upon 250-nm
excitation. This band is attributed to Cu+ centers in the samples grown. The mechanisms of capture and recombination during thermoluminescence are considered. 相似文献
5.
O. V. Ovchinnikov A. B. Evlev M. A. Efimova V. G. Klyuev A. N. Latyshev A. N. Utekhin A. M. Kholkina 《Journal of Applied Spectroscopy》2005,72(6):809-813
An anti-Stokes luminescence band with λmax = 515 nm of microcrystals of solid AgCl0.95I0.05 solutions excited by a radiation flux of density 1013–1015 quanta/cm2·sec in the range 600–800 nm at 77 K was detected. It is shown that the intensity of this luminescence and the frequency of
its excitation depend on the prior UV-irradiation of samples. Analysis of the stimulated-photoluminescence spectra and the
anti-Stokes luminescence excitation spectra of the indicated microcrystals has shown that to the centers of anti-Stokes luminescence
excitation correspond local levels in the forbidden band of the crystals. These states are apparently due to the atomic and
molecular disperse silver particles that can be inherent in character or formed as a result of a low-temperature photochemical
process.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 738–742, November–December, 2005. 相似文献
6.
We show that when polystyrene is exposed (for 15–60 sec) to a UV laser light beam (λ = 248 nm), its absorption and luminescent
properties change significantly. In the irradiated polymer, optical centers are formed with absorption bands in the 280–460
nm region and fluorescence bands in the 330–520 nm region. We have established the chemical structure of the optical centers
for fluorescence of polystyrene.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 54–58, January–February, 2006. 相似文献
7.
Spectra of x-ray radiation-induced absorption of SrCl2−Ce crystals in the region of 340–830 nm under the effect of selective irradiation in the induced-absorption bands by both
conventional and laser sources are investigated. It is established that irradiation of sufficient intensity causes irreversible
photochemical transformations of PC, PC+, and Ce2+ color centers their destruction, and restoration of the transparency of the crystals.
To whom correspondence should be addressed.
I. Franko Lvov State University, 8, Kirill and Mefodii Str., Lvov, 290005, Ukraine. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 66, No. 5, pp. 666–668, September–October, 1999. 相似文献
8.
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
9.
Doping of ZnS crystals with background impurities and ZnS:Al crystals by various concentrations of copper from a bismuth melt
has been carried out. The photoluminescence spectra of the starting ZnS crystals annealed in the bismuth melt and doped by
copper have been investigated. Interpretation of the experimental results according to the model in which the associates (Cu
Zn
′
Cu
i
●
) are responsible for the B-Cu band (≈460 nm) and the donor—receptor pairs [Cu
i
●
-(Cu
Zn
′
Cu
i
●
)] are responsible for the G-Cu band (≈505 nm) is given. It is assumed that doping by copper from a bismuth melt is accompanied
by the separation of a CuxS-type phase. It has been shown that heat treatment of ZnS crystals in the Bi melt does not lead to the appearance of luminescence
centers based on BiZn, BiS, and Bii.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 6, pp. 794–798, November–December, 2005. 相似文献
10.
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
11.
Hrant Yeritsyan Vachagan Harutiunian Volodia Gevorkyan Norair Grigoryan Eleonora Hakhverdyan Sergey Nikoghosyan Aram Sahakyan Rudolf Gevorgyan Hakob Sargisyan Yeghis Keheyan 《Central European Journal of Physics》2005,3(4):623-635
Infrared (IR) absorption and luminescence in chemically and radiation-modified natural Armenian Zeolite (clinoptilolite) samples
have been studied. The luminescence was studied in 390–450 nm and 620–710 nm wavelength bands, and the IR measurements were
carried out in the 400–5400 cm−1 range. It is shown that the luminescence intensity depends on the content of pure clinoptilolite in the samples and, probably
on the distribution of “passive” luminescence centers over Si and Al sites that became “active” under radiation or chemical
treatment. The samples of electron irradiated clinoptilolite have higher luminescence intensity than the chemically and thermally
treated ones. A decrease in the intensity of IR absorption bands at 3550 cm−1 and 3650 cm−1 was found after irradiation. 相似文献
12.
The thermal- and photo-induced transformations of luminescence centers in anion-defective crystals of α-Al2O3 have been investigated. It has been found that the exposure of crystals to ultraviolet light at temperatures in the range
50–900°C leads to substantial changes in their thermoluminescence and radioluminescence spectra. According to the optical
absorption and photoluminescence data, the detected F-type centers have been identified and the temperature ranges of the F → F
+ → F
2 transformations and their possible mechanisms have been determined. The special attention has been drawn to the detailed
similarity in the formation of complex F
2-type centers in the initially perfect α-Al2O3 crystals irradiated with fast neutrons and in the studied anion-defective crystals. 相似文献
13.
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
14.
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
15.
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
16.
The energy level structure of F
3
+
laser color centers in crystals of LiF is discussed. A high-power laser (λ
ex=920 nm) is used to excite luminescence from LiF crystals with F
3
+
centers via two-photon absorption, and the dependence of the polarization and intensity of this luminescence on the polarization
of the laser light is measured and calculated. It is shown that the two-photon transition involves the excitation of a previously
unknown state of the F
3
+
center—a spin singlet whose wave function has 1
A
1 symmetry.
Fiz. Tverd. Tela (St. Petersburg) 39, 1373–1379 (August 1996) 相似文献
17.
I. Kh. Abdukadyrova 《Journal of Applied Spectroscopy》2003,70(6):890-895
The characteristic features of the process of radiation-defect formation and of a change in the structural and optical properties of corundum crystals exposed to reactor radiation have been investigated by spectroscopic methods. The dose dependences of the generation of a number of color and luminescence centers, the regularities of their thermal and photodecoloration, and the energies of activation of the centers have been determined. The influence of the overlapping of the absorption and luminescence centers has been estimated. The radiation-induced change in the structural parameters of the crystal and in the characteristics of the main reflexes has been determined. It has been established that at large reactor radiation fluxes the processes of damage of the crystal are accelerated and a small halo appears at 12.5°. The possible mechanism of damage and disordering of the structure of corundum irradiated in the reactor with a fairly large flux is discussed. 相似文献
18.
Results of comprehensive research into optical and luminescent-kinetic characteristics of europium-doped cadmium iodide crystals
excited by nitrogen laser radiation, α-particles, and x-rays are presented. Crystals under study have been grown by the Bridgman–Stockbarger
method. The doping EuCl3 admixture was introduced into the charge in quantities of about 0.05 and 1.0 mol%. Impurity absorption detected in the near-edge
region of the crystals is interpreted as part of the Eu2+ ion long-wavelength band associated with f–d-transitions. The cation impurity and matrix defects in CdI2:Eu2+ crystals create complex centers responsible for emission with a maximum in the 580–600-nm region. The short component in
the luminescence decay kinetics of weakly-doped crystal excited by α-particles and x-ray photons is due to the exciton emission
characteristic of CdI2. The slow component in the scintillation pulse results from recombination of charge carriers followed by creation of exciton-like
states on the defect-impurity centers. Laser or x-ray excitation induces light-sum accumulation on the trapping levels at
a depth of 0.2–0.6 eV that is mainly related to matrix microdefects. Trapping centers associated with the chlorine impurity
are observed in the heavily-doped crystal. Photostimulated luminescence at 85 K arising at the electron stage of the recombination
process is caused by recombination of electrons released from F-type centers with holes localized near the activator.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 76, No. 3, pp. 358–364, May–June, 2009. 相似文献
19.
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
20.
It is established that doping of CdS polycrystalline films with alkaline metals (Li, Na, K, Cs) results in an increase of
luminescence intensity by 3–5 times compared with pure films. This increase is accounted for by the placement of alkaline-metal
ions in V
Cd
2−
cation vacancies, which are nonradiative recombination centers in these films. From the dependences of the luminsecence intensity
of the doped films on the synthesis conditions (deposition temperature, concentration of doping impurities, type of doping
metal), the parameters that ensure the maximum luminescence intensity of the films are determined as Tdep ≈ 450°C and CMe = 1·10−5 at %. The luminescence intensity decreases by 1–3% upon exposure of the films to UV light (λmax = 365 nm, I = 1021 quanta·sec·cm−1) for several hours. This is indicative of the stability of these films against UV radiation.
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Translated from Zhurnal Prikladnoi Spektroskopii Vol. 74, No. 3, pp. 362–366, May–June, 2007. 相似文献