共查询到20条相似文献,搜索用时 31 毫秒
1.
V. L. Dubovskii A. L. Mikhal’chuk T. F. Raichenok A. N. Sobchuk A. A. Sukhodola G. B. Tolstorozhev 《Journal of Applied Spectroscopy》2006,73(3):347-352
We have used steady-state fluorescence spectroscopy and pulsed kinetic fluorimetry with high time resolution to experimentally
study the spectral and temporal characteristics of luminescence of immunoactive 8-aza-D-homogona-1,3,5(10), 13-tetraene-12,17a-dione
(8-aza-D-homogonane) molecules in the gas phase. We have established the existence of several centers emitting long-wavelength
and short-wavelength fluorescence. The fluorescence of high-temperature 8-aza-D-homogonane vapor (T = 550 K) when excited
by radiation with λex = 266 nm is represented by two spectrally separated emission bands with maxima λ
max
fl
= 465 nm and λ
max
fl
= 365 nm. Analysis of the distribution of fluorescence decay times for 8-aza-D-homogonane showed that in the spectral range
of the emission wavelengths 360–590 nm, the fluorescence decay kinetics contains three components with average lifetimes <200
psec, 2.8 nsec and 13.5 nsec. The multicenter nature of luminescence of 8-aza-D-homogonane was confirmed by direct measurements
of instantaneous fluorescence spectra in different stages of luminescence decay.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 3, pp. 309–314, May–June, 2006. 相似文献
2.
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
3.
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
4.
The effect of temperature on the spectral luminescence characteristics of PbWO4:Tb3+ crystals with synchrotron and laser excitation is studied. If PbWO4:Tb3+ is excited by synchrotron radiation with λ = 88 nm at 300 K, a faint recombination luminescence of the impurity terbium is
observed against the matrix luminescence. When the temperature is reduced to 8 K, the luminescence intensity of PbWO4:Tb3+ increases by roughly an order of magnitude and the characteristic luminescence of the unactivated crystal is observed. Excitation
of PbWO4:Tb3+ by a nitrogen laser at 300 K leads to the appearance of emission from Tb3+ ions. At 90 K, a faint matrix luminescence is observed in addition to the activator emission. The formation of the luminescence
excitation spectra for wavelengths of 60–320 nm is analyzed and the nature of the emission bands is discussed. 相似文献
5.
Abhay D. Deshmukh S. J. Dhoble S. V. Godbole M. K. Bhide D. R. Peshwe 《Indian Journal of Physics》2009,83(4):423-428
The calcium aluminates doped with Eu ions, Ca5Al8O14: Eu, phosphors are prepared by the combustion method. The formation of crystalline aluminates was confirmed by X-ray diffraction
pattern. The prepared phosphors were characterized by SEM, TGA, DTA, particle size analyzer and Photoluminescence (PL) techniques.
From the UV-excited luminescence spectra it was found that the Eu ions acts as a luminescent centre with luminescence at the
blue (λ
max = 470 nm) region due to 4f
65d
1 → 4f
7 transition. The excitation spectra show the broad band at 355 nm wavelength (λ
em = 470 nm). The excitation 355 nm is a mercury free excitation and therefore Ca5Al8O14: Eu may be useful for the solid state lighting phosphor in lamp industry.
相似文献
6.
A technique is developed for measuring luminescence spectra of hafnium dioxide using a hydrogen lamp as an excitation source.
The luminescence spectra of the as-grown and annealed hafnium dioxide films prepared by chemical deposition from volatile
hafnium dipivaloylmethanate on the Si(111) substrates are measured at room temperature. Intense luminescence at λ ≌ 280 nm
is characteristic of nanocrystallites of monoclinic modification. The band gap width is found to be ≌ 5.76 eV. It is shown
that the film composition significantly deviates from the stoichiometric one.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 63–67, April, 2007. 相似文献
7.
V. S. Vavilov M. V. Chukichev R. R. Rezvanov A. A. Klyukanov K. D. Sushkevich E. K. Sushkevich 《Physics of the Solid State》1997,39(9):1358-1363
The cathodoluminescence (CL) in ZnSe crystals annealed at T=1200 K in a Bi melt containing an aluminum impurity is investigated. The spectra are recorded for different excitation levels,
temperatures, and detection delay times t
0. As t
0 is increased, the intensity of the orange band at λ
max=630 nm (1.968 eV) in the CL spectrum decreases in comparison to the intensity of the dominant yellow-green band at λ
max=550 nm (2.254 eV), whose half-width increases in the temperature range 6–120 K and then decreases as the temperature increases
further. It is shown that such behavior of the yellow-green band is caused by the competition between two processes: recombination
of donor-acceptor pairs and of free electrons with holes trapped on acceptors. The former mechanism is dominant at low temperatures,
and the latter mechanism is dominant at high temperatures. At T∼120 mK the contributions of the two mechanisms to the luminescence are comparable. The resultant structureless band then
achieves its greatest half-width, which is dictated by the interaction of the recombining charge carriers with longitudinal-optical
and longitudinal-acoustic phonons and with the free-electron plasma. The mean number of longitudinal-optical phonons emitted
per photon is determined mainly by their interaction with holes trapped on deep acceptors in the form of Al atoms replacing
Se. The donor in the pair under consideration is an interstitial Al atom.
Fiz. Tverd. Tela (St. Petersburg) 39, 1526–1531 (September 1997) 相似文献
8.
A. K. Shuaibov 《Journal of Applied Spectroscopy》1999,66(2):256-262
Survey emission spectra in the region of 190–600 nm and time and service-life characteristics of a transverse nanosecond discharge
in He/Ar/CF2Cl2(CCl4) mixtures at a pressure of 10–100 kPa are investigated. In the emission spectra, excited products of the decomposition of
freons—C2(A−X), CN(B−X), Cl
2
*
, C*, Cl*, and Cl+*— and the emission of ArF at λ=193 nm are revealed. The emissions of Cl
2
*
at λ=258 nm and ArF at λ=193 nm were the most intense. The discharge in the He/Ar/CF2Cl2 mixture is a multiwave emission source with λ=258 nm Cl
2
*
193 nm ArF, and probably, 175 nm Arcl. It is of interest for applications in UV-VUV-range pulse photometry. The duration
of the emission on Cl
2
*
, ArF, ArI, ClI, and ClII transitions in the discharge in the Ar/CF2Cl2 mixture (P=10–20 kPa) was 200–300 nsec. With adding He and increasing pressure to 100 kPa the duration of the emission decreased
by a factor of 1.5–2. The basic mechanisms of the formation of Cl2, ArF, and CN(B) molecules in the transverse-discharge plasma are considered.
Uzhgorod State University, 46, Pidgirna Str., Uzhgorod, 294000, Ukraine. Translated from Zhurnal. Prikladnoi Spektroskopii,
Vol. 66, No. 2, pp. 241–246, March–April, 1999. 相似文献
9.
The emission spectra of nonlinear media with periodical modulation of the second-order susceptibility that are based on synthetic
opals infiltrated by Ba(NO3)2, LiIO3, and KH2PO4 are studied using radiation with λ = 400 and 407 nm for excitation. The spectral angular distribution of the emission in
the range of 420–650 nm is revealed, as well as the dependence of its spectrum on the photonic stop-band parameters and the
exciting radiation characteristics. The emission spectrum of samples with a low dielectric contrast has the shape of a symmetric
band with a maximum at 525 nm and a half-width of about 100 nm. The observed emission is interpreted as spontaneous parametric
light scattering in a spatially inhomogeneous nonlinear medium. 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.
We report here the luminescence spectra of certain rare earth ions (Eu3+, Tb3+ & Ho3+) doped B2O3-BaO-LiF/AiF3 based on the measurements of emission and decay curves of prominent emission transitions. For both the reference host glasses,
FTIR, XRD, DTA-TG profiles have been recorded to understand their structural and thermal properties. Eu3+ doped glasses have shown five emission transitions of 5D0 → 7F01,2,3 & 4 located at 580nm, 593nm, 615nm, 655nm and 704nm respectively with an excitation at λexci = 392 nm (7F0 → 5L6). Also under an UV source, these europium glasses have displayed a bright red emission from their surfaces. Tb3+ glasses have exhibited four emission bands of 5D4 → 7F6,5,4,3 at 491nm, 547nm, 588nm and 625nm respectively with an excitation at λexci = 376 nm (7F6 → 5G6). Intense green emission from the glass surfaces has been noticed upon exposure to the UV source. Prominently bluish-green emission has been
noticed from the surfaces of the holmium glasses under an UV source and same emission transition (5F4 → 5I8) at 519 nm with an excitation at λexci = 389 nm (5I8 − 5G4) has also been obtained from their measured emission spectra. For all the prominent emissions of the rare earth glasses,
decay curves have been measured to compute their lifetimes. 相似文献
12.
M. M. Chugunova I. A. Kamenskikh V. V. Mikhailin S. A. Usenko 《Optics and Spectroscopy》2010,109(6):887-892
We present the results of studying the luminescence properties of transparent ceramics Y3Al5O12:Yb obtained by the vacuum sintering and nanocrystalline technology. In the course of research, we measured the luminescence
and luminescence excitation spectra, as well as the temperature and kinetic behavior of luminescence. Our results are analyzed
in comparison with the characteristics of corresponding single crystals. We revealed that processes of generation and relaxation
of electronic excitations that occur in ceramics, in particular, in the charge transfer state, are similar to processes occurring
in crystals. The behavior of two charge-transfer luminescence bands at 340 and 490 nm is studied. In the range 300–600 nm,
we revealed a broad emission band of radiation of other type, which is also observed in spectra of undoped ceramics. This
broad band is attributed to F+ centers. Emission and excitation spectra of charge transfer luminescence at a maximum of the temperature dependence of 100
K are measured for the first time. We found that, upon excitation in the charge transfer band, luminescence in ceramics is
more intense than in single crystals with similar concentrations of Yb and has a higher quenching temperature. 相似文献
13.
V. M. Marchenko L. D. Iskhakova A. V. Kir’yanov V. M. Mashinsky N. M. Karatun E. M. Sholokhov 《Laser Physics》2012,22(1):177-183
Yb2O3 polycrystals with a size of up to 10 mm are synthesized using the sintering and melting of the ultrapure Yb2O3 powders by the CO2-laser radiation with the power P
L ≤ 100 W at the wavelength λ = 10.6 μm at the melting point T
m = 2703 K, forming due to surface tension in melt, and crystallization in air. The analysis of the polycrystal microstructure
using the methods of optical and electron microscopy and X- ray diffractometry shows that perfect oxide crystallites are formed
in the course of crystallization after melting-through. The transformation of the luminescence and selective heat radiation
(SHR) spectra of the Yb2O3 polycrystals is studied under the resonant excitation at λ ≈ 975 nm using a laser diode and the laser heating at the wavelength
λ = 10.6 μm. When the resonant excitation power of the Yb3+ ions increases from 0.15 to 4.5 W, the Stokes luminescence of the Yb2O3 polycrystals is sequentially transformed into SHR and the thermal radiation of the crystal lattice. The transformation of
the emission spectra of the Yb2O3 polycrystals with an increase in the laser heating intensity by about four orders of magnitude can be represented as the
low-temperature heat radiation, spectral burst of the thermodynamically nonequilibrium SHR of the Yb3+ ions, and the high-temperature radiation of the crystal lattice. The temperature dependence of the luminescence spectra and
SHR of the Yb2O3 polycrystals on the intensity of the laser and laser-thermal excitation and the concentration quenching of the Yb3+ luminescence in oxides indicate the key role of the interaction of the f-electron shell of the Yb3+ ions with the natural oscillations of the crystal lattice in the processes of the multiphonon excitation and nonradiative
(multiphonon) and radiative (vibronic) relaxation. 相似文献
14.
Fluorescence of symmetric polymethine dye solutions (λ
abs
max
≈ 700 nm) upon anti-Stokes excitation by cw radiation of a titanium-sapphire laser (781 nm) is first investigated. A series
of six compounds with analogous composition and spectral and luminescent properties is investigated. It is demonstrated that
in addition to the anti-Stokes component, the Stokes component with a maximum at 820 nm (referred to the H-aggregates of initial
dyes) is observed in the fluorescence spectra of solutions of the examined molecules when dye concentration increases to 10−3 M. Dependences of the anti-Stokes and Stokes component intensities on the exciting radiation power are obtained that confirm
a linear excitation character. On examples of xanthene and polymethine dyes, the use of organic fluorophors for anti-Stokes
laser cooling and some other possible applications of the anti-Stokes fluorescence are discussed.
__________
Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 3, pp. 63–70, March, 2007. 相似文献
15.
P. P. Pershukevich D. V. Shabrov V. P. Osipov J. Schreiber V. A. Lapina 《Journal of Applied Spectroscopy》2011,78(4):524-533
This is a study of the luminescence properties of coatings formed on aluminum alloys by anodizing in electrolytic solutions
based on oxalic, sulfuric, and tartaric-sulfonic acids. At least two emission centers, with band maxima in the ranges of 390–410
and 470–510 nm, can be reliably identified in the photoluminescence spectra. The first type of center is characterized by
single-band photoluminescence excitation spectra and the second, by two-band spectra. An analysis of the two-band photoluminescence
excitation (PLE) spectra in the range of 470–510 nm shows that the position of the narrow short-wavelength PLE spectrum near
272 nm is independent of the type of acid used in the anodization process. The position and shape of the other PLE spectral
bands depend both on the type of acid used and on the processing of the alloy or alumina surfaces. It is assumed that defect-free
alumina centers are responsible for the 272 nm PLE band, while the other photoluminescence bands are caused primarily by different
divacancies of oxygen (F2+ {F_2^+} , F
2, and F2+2 {F_2^{+2}} centers) whose origin is governed by the type of electrolyte. 相似文献
16.
I. Kh. Akopyan B. V. Bondarenko O. N. Volkova B. V. Novikov T. A. Pavlova 《Physics of the Solid State》1997,39(1):58-63
Low-temperature (4.2–130 K) photoluminescence spectra of HgI2 crystals have been measured in the 540–700 nm region. An analysis of the characteristics (intensity vs temperature and excitation
power relations, afterglow times, excitation spectra) of the 560, 620, and 635 nm emission bands suggests the following assignments:
the 560 nm band is due to radiative annihilation of excitons bound to mercury vacancies, and the “red” emission originates
from recombination of free (620 nm) and donor-localized (635 nm) electrons with a hole-filled acceptor level. The energies
of the corresponding donor and acceptor levels have been estimated. New emission bands at 540, 545, and 575 nm have been discovered,
and their origin discussed.
Fiz. Tverd. Tela (St. Petersburg) 39, 67–73 (January 1997) 相似文献
17.
O. B. Tagiev S. A. Abushov F. A. Kazymova K. O. Tagiev 《Journal of Applied Spectroscopy》2006,73(4):541-545
We present the results of a study of the luminescence and luminescence excitation spectra, and also the luminescence kinetics
of a BaSiO3:Yb3+ crystal. We have established the mechanism for emission by the matrix and energy transfer from the matrix to the rare earth
ion.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 478–482, July–August, 2006. 相似文献
18.
The form of the stationary luminescence spectra of excitons, localized by composition fluctuations, in disordered solid solutions
under weak excitation is calculated. The tail states for which there are no nonradiative transition channels are distinguished
by means of continuum percolation theory. Such states are responsible for the “zero-phonon” luminescence band. The shape of
the short-wavelength luminescence band edge is determined mainly by the number of isolated localizing clusters and their smallest
complexes, which decreases rapidly near the mobility threshold. The real luminescence spectrum is due to the simultaneous
emission of phonons. The phonon emission determines the form of the long-wavelength wing of the emission band. The computed
shape of the emission spectrum is compared with the experimental luminescence spectra of the solid solution CdS(1−c)Sec.
Pis’ma Zh. éksp. Teor. Fiz. 65, No. 3, 274–279 (10 February 1997) 相似文献
19.
Strong green luminescence of Ni2+-doped ZnS nanocrystals 总被引:1,自引:0,他引:1
P. Yang M. Lü D. Xü D. Yuan J. Chang G. Zhou M. Pan 《Applied Physics A: Materials Science & Processing》2002,74(2):257-259
ZnS nanoparticles doped with Ni2+ have been obtained by chemical co-precipitation from homogeneous solutions of zinc and nickel salt compounds, with S2- as precipitating anion, formed by decomposition of thioacetamide (TAA). The average size of particles doped with different
mole ratios, estimated from the Debye–Scherrer formula, is about 2–2.5 nm. The nanoparticles could be doped with nickel during
synthesis without altering the X-ray diffraction pattern. A Hitachi M-850 fluorescence spectrophotometer reveals the emission
spectra of samples. The absorption spectra show that the excitation spectra of Ni-doped ZnS nanocrystallites are almost the
same as those of pure ZnS nanocrystallites (λex=308–310 nm). Because a Ni2+ luminescent center is formed in ZnS nanocrystallites, the photoluminescence intensity increases with the amount of ZnS nanoparticles
doped with Ni2+. Stronger and stable green-light emission (520 nm) (its intensity is about two times that of pure ZnS nanoparticles) has
been observed from ZnS nanoparticles doped with Ni2+.
Received: 18 December 2000 / Accepted: 17 March 2001 / Published online: 20 June 2001 相似文献
20.
A. N. Georgobiani B. G. Tagiev O. B. Tagiev R. B. Dzhabbarov S. A. Abushov F. A. Kazymova C. Barthou P. Benalloul V. M. Salmanov 《Journal of Applied Spectroscopy》2007,74(3):369-373
We have studied the photoluminescent properties of MIIGa2S4:Er3+ polycrystals (MII = Eu, Yb, Ca) for excitation by radiation with λ = 976 nm as a function of temperature. The samples were obtained by solid-state
reaction. We have studied the comparative characteristics of the anti-Stokes and IR luminescence of these luminophores. We
have determined the mechanisms for anti-Stokes emission of MIIGa2S4:Er3+ crystals.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 3, pp. 332–335, May–June, 2007. 相似文献