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1.
The study puts toward a theoretical model describing the fluorescence parameters for concentrated solid solutions consisting
of complex molecules of two types (donor-acceptor) with nonradiative transfer of electronic-excitation energy with intense
pulse excitation. Consideration is given to the dynamics of quenching of the luminescence of the donor molecules due to transfer
of electronic-excitation energy to the acceptor molecules. Numerical results are presented in the form of approximation formulas.
To whom correspondence should be addressed.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 66, No. 5, pp. 652–656, September–October, 1999. 相似文献
2.
Hideaki Matsueda 《Journal of Russian Laser Research》2009,30(5):525-532
We give a real use of the time–energy uncertainty principle for nanostructure circuit design consideration. The range of virtual
as well as real photons mediating interactions among nanostructures is estimated as the product of the photon lifetime and
its velocity, as in the meson exchange model for nucleon. This gives a new vista for near field interactions of electric nature
in a solid, especially for the nonradiative internal energy transfer, which may be called the resonance dynamic multipole–multipole
interaction (RDMMI). The length of the transition dipole is deduced from the 0.3 meV fine structure in our microphotoluminescence
spectra of an individual coupled GaAs asymmetric quantum dots. Various multipoles and their potentials are estimated employing
this dipole length. Then the ranges and lifetimes of the RDMMI are derived and plotted, together with the spatiotemporal consideration
and the provisional structure of quantum circuits. 相似文献
3.
A theoretical study was carried out to investigate concentration self-quenching which is nonlinear in intensity in a molecular
system caused by nonradiative electronic excitation energy transfer to relatively long-lived acceptors that are formed in
a solution and whose function is performed by molecules that have acquired the triplet state. It is shown that at ratios of
constants of radiative and nonradiative transitions typical of complex molecules at concentrations of ∼10−3–10−2 mole/liter substantial (2- to 10-fold) fluorescence takes place at intensities of excitation of ∼104–103 of the intensity of saturation for a singlet subsystem. Polarization characteristics of the system are analyzed.
Belarusian State University, 4, F. Skorina Ave., 220050, Minsk, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 64, No. 6, pp. 729–733, November–December, 1997. 相似文献
4.
To a first approximation in perturbation theory, we have obtained expressions for the rate constants for intersystem crossings
in acceptor molecules. We show that exchange interactions between the components of the donor-acceptor pair can change the
probability of intersystem crossings for both radiative T → S0 and nonradiative S1 → T transitions. The theoretical conclusions are supported by the results of experimental studies.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 550–553, July–August, 2006. 相似文献
5.
V. A. Pustovarov B. V. Shul'gin É. I. Zinin A. Yu. Kuznetsov 《Russian Physics Journal》1996,39(11):1102-1113
Luminescence spectroscopy with subnanosecond time resolution is used to study features of nonequilibrium processes excited
in several broad-zone dielectrics (mainly inorganic scintillators) by pulses of synchrotron radiation (SR). When excitation
density exceeds a certain level, which is different for each material, there is an abrupt change in the kinetics of relaxation
of the nonequilibrium states. This change is accompanied by nonuniform broadening or shortwave shifting of the luminescence
spectrum and a drop in quantum light yield. The decay time for natural luminescence decreases by 1–3 orders, to nanoseconds,
and is independent of temperature within the range 80–450 K. The build-up stage disappears in the kinetics of luminescence
of Ce3+-centers and decay time is reduced by a factor of 2–4. Density effects are found to be independent of the conditions under
which the material is exposed to SR. A model is proposed in which density effects are related to nonradiative energy transfer
from the upper excited states of the luminescence centers to external quenching centers. The contribution of the space charge
induced by SR is also examined.
Ural State Technical University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 11, pp. 120–135, November,
1996. 相似文献
6.
S. L. Bondarev V. N. Knyukshto A. A. Turban A. A. Ishchenko A. V. Kulinich 《Journal of Applied Spectroscopy》2006,73(1):25-34
We have studied the luminescent spectral properties and calculated the quadratic polarizability of dimethine, tetramethine,
and hexamethine merocyanines based on 1,3-dihydro-1,3,3-trimethyl-(2H)-indol-2-ylidene and malonodinitrile in solutions and
polymer films at room temperature and 77 K. We have shown that increasing the polarity of the solvent and lengthening the
polymethine chain in the studied merocyanines lead to an increase in fluorescence quantum yields and narrowing of the fluorescence
bands. This is explained by the decrease in bond length alternation and weakening of vibronic interactions in the singlet-excited
fluorescent state. The mirror symmetry in the structured absorption and fluorescence spectra of merocyanine dyes in ethanol
at 77 K, observed here for the first time, is due to enhancement of electrostatic interactions of the merocyanine and solvent
molecules. Increased stiffness of the medium considerably decreases the probability of nonradiative processes, and the major
channel for deactivation of the electronic excitation energy at 77 K is fluorescence. The higher values of the quadratic polarizability
(6.0·10−28 esu in ethanol and 3.3·10−28 esu in chloroform) for hexamethine merocyanine, estimated by the solvatochromic method, lets us consider this compound as
a promising material for designing nonlinear optical converters for harmonics of laser radiation.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 26–35, January–February, 2006. 相似文献
7.
S. L. Efimova A. V. Sorokin A. N. Lebedenko Yu. V. Malyukin E. N. Obukhova 《Journal of Applied Spectroscopy》2006,73(2):164-170
Utilizing forced concentration of carbocyanine dye molecules DiI and DiD within a surfactant micelle, we have detected nonradiative
transfer of electronic excitation energy for low initial dye concentrations in the aqueous micellar solution. Luminescence
and fluorescence anisotropy decay studies allowed us to establish that in the micelles, the hydrophilic head of the dye is
in contact with the water while the C18H37 groups are located in the hydrocarbon core of the micelle. We show that due to
the structural features of the DiD acceptor molecule, rotational diffusion of the acceptor in the micelle is more free than
for the donor DiI, the motion of which is constrained in the micelle.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 2, pp. 152–157, March–April, 2006. 相似文献
8.
We have shown that in slow thermal reactions of complex molecules, effects of nonradiative transitions due to quantum beats
between resonant states of the combining molecular structures can be observed in conventional (without high time resolution)
IR absorption spectra, as oscillations in the intensities of individual lines. We suggest a method to ensure the required
level of coherence for the oscillations in an ensemble of molecules, based on application of pulsed heating to the molecular
system. Detection of the qualitatively new effects by traditional IR spectroscopy methods, including their quantitative characteristics,
considerably increases the information content of the spectral data obtained and makes it possible to use such highly developed
experimental methods to study chemical reactions, including the reaction dynamics. The range of these reactions is quite broad,
encompassing both “laboratory” and “natural” (geochemistry, ecology, etc.) processes with characteristic times on the order
of minutes or more.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 6, pp. 738–743, November–December, 2007. 相似文献
9.
A. V. Belousov V. A. Kovarskii 《Journal of Experimental and Theoretical Physics》1998,87(6):1053-1057
We examine nonradiative transitions in molecules with allowance for the effect of a classical polar exterior medium on tunneling
charge transport. The approach allows for the vibrational frequencies of a molecule in the electron transition. In the case
of slow fluctuations, the theory predicts a low-temperature (non-Arrhenius) increase in the tunneling nonradiative transition
rate, and the results agree qualitatively with the experimental data. When the fluctuations of the exterior medium are rapid,
at certain values of the molecular parameters the tunneling decay rate is found to decrease with increasing temperature because
the conditions needed for resonant tunneling are violated.
Zh. éksp. Teor. Fiz. 114, 1944–1953 (December 1998) 相似文献
10.
Yu. P. Morozova O. M. Zharkova T. Yu. Balakina V. Ya. Artyukhov B. V. Korolev 《Russian Physics Journal》2011,54(5):594-600
The fluorescent probe molecule – laurdan (6-dodekanoil-2-dimetilamin naphthalene) – is investigated by experimental and quantum-chemical
methods. The influence of the structure non-rigidity on the dipole moments, arrangement of energy levels, and distribution
of charges in the laurdan molecule is studied. An optimized structure is obtained and analyzed by the molecular dynamics method.
Several structures with different rotation angles of the dimethylamino group are investigated, for which energy, oscillator
forces, and nature of electron states are calculated. Fluorescence spectra of the laurdan molecule in an inert solvent are
interpreted. Centers of possible interaction of the molecule with a proton-donor solvent are established. Rate constants of
radiative and nonradiative processes and quantum fluorescence yields of the examined probe are calculated. 相似文献
11.
V. Yu. Plavskii V. A. Mostovnikov G. R. Mostovnikova A. I. Tret’yakova 《Journal of Applied Spectroscopy》2007,74(1):120-132
We have studied the spectral fluorescence and polarization characteristics of Z,Z-bilirubin IXα, at room temperature in chloroform
and in aqueous buffer medium, within an equilibrium complex with human serum albumin (HSA), and also under low temperature
conditions (T = −100°C) in isobutyl alcohol. We have observed a bathochromic shift of the fluorescence spectra, which is most
pronounced for the bilirubin-albumin complex. The following are considered as possible reasons for the observed dependence
of the position of the fluorescence (fluorescence excitation) spectra on the excitation (detection) wavelength: structural
and spectral differences between the chromophores making up the bilirubin molecule; conformational heterogeneity of the pigment
in solution; a contribution to the fluorescence from molecules which have not completed the vibrational relaxation process;
inhomogeneous orientational broadening of the levels; heterogeneity of the microenvironment of the chromophores in the protein
matrix. We show that polarized fluorescence of bilirubin occurs at room temperature, due to the anomalously short fluorescence
lifetime τ (picosecond or subpicosecond ranges). Despite such a short τ, the absorption and emission polarization spectra
suggest the presence of intramolecular nonradiative singlet-singlet energy transfer when bilirubin is excited to high vibrational
sublevels of the S1 state (degree of polarization p = 0.11–0.12). When fluorescence is excited on the long-wavelength slope of the absorption
band, no transfer occurs: the degree of polarization (p = 0.46−0.47) is close to the limiting value (p = 0.50). We discuss
the question of the role played by exciton interactions between chromophores in the bilirubin molecule when it is excited.
__________
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 1, pp. 108–119, January–February, 2007. 相似文献
12.
Feng Liu An Tai M. Gaździcki R. Stock 《The European Physical Journal C - Particles and Fields》1999,8(4):649-654
Transverse momentum event–by–event fluctuations are studied within the string–hadronic model of high energy nuclear collisions,
LUCIAE. Data on non–statistical fluctuations in p+p interactions are reproduced. Fluctuations of similar magnitude are predicted for nucleus–nucleus collisions,
in contradiction to the preliminary NA49 results. The introduction of a string clustering mechanism (Firecracker Model) leads
to a further, significant increase of fluctuations for nucleus–nucleus collisions. Secondary hadronic interactions, as implemented in LUCIAE, cause only a small
reduction of fluctuations.
Received: 23 October 1998 / Published online: 11 March 1999 相似文献
13.
We have used computer simulation to compare theoretical models for describing interisomer transitions of complex molecules
and their spectral manifestations. We have shown that the kinetics of the intramolecular processes and time-resolved spectra,
taking into account quantum beats between resonant (bound) states of the isomers (or isolated level subsystems for one isomer
form), can be described not only by using a general molecular model in which the resonant levels of the subsystems act as
a single level of a mixed state, with a time-dependent wave function in the form of quantum beats, but also by using a model
interpreting the beat effect as a nonradiative transition. These models are completely equivalent: the parameters describing
them have the same values, and numerical differences in the results obtained are no greater than 1% and are due to numerical
round-off errors in the calculations and not differences between the models. The second model is preferred because it is graphically
clear and conventionally used for describing and interpreting intramolecular processes, but it does take somewhat longer (∼10%)
to run the simulation.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 1, pp. 36–41, January–February, 2006. 相似文献
14.
C.Y. Liu S.F. Yoon J.H. Teng J.R. Dong S.J. Chua 《Applied Physics A: Materials Science & Processing》2008,91(3):435-439
GaInP/AlGaInP triple quantum well (TQW) lasers, grown by metalorganic chemical vapor deposition (MOCVD) using tertiarybutylarsine
(TBAs) and tertiarybutylphosphine (TBP), were fabricated with a pulsed anodic oxidation (PAO) process. The devices worked
at room temperature (RT) with the lowest threshold current density (Jth) of 1.5 kA/cm2 ever reported for GaInP/AlGaInP lasers grown using TBAs and TBP. Temperature dependent (35–250 K) electroluminescence (EL)
study of the GaInP/AlGaInP laser diode showed almost the same luminescence quenching behavior at a high temperature region
(120–250 K), independent of the injection current (100–150 mA). A model involving a nonradiative recombination mechanism was
presented to interpret the EL quenching behavior over the experimental temperature range. The nonradiative recombination centers
in the Al-containing barrier or cladding layer are believed to contribute to the loss of carriers via nonradiative recombination.
PACS 78.60.Fi; 71.20.Nr; 78.67.De; 81.15.Gh; 42.55.Px 相似文献
15.
Yu. P. Piryatinski L. A. Dolgov O. V. Yaroshchuk T. A. Gavrilko S. K. Lazarouk 《Optics and Spectroscopy》2010,108(1):70-79
The fluorescence of samples of porous silicon of various morphologies that are filled with a liquid crystal (LC), n-pentyl-n′-cyanobiphenyl (5CB), is studied. The fluorescence spectra of the sample, along with the long-wavelength band of porous silicon
with a maximum in the range 627–667 nm, exhibit a short-wavelength band of 5CB with a maximum in the range 385–410 nm. The
radiative relaxation times of porous silicon and 5CB lie in the micro- and nanosecond ranges, respectively. It is found that
the filling of pores with 5CB enhances the fluorescence of porous silicon by two to three times. This enhancement is caused
by non-radiative energy transfer from 5CB to the porous matrix as a result of efficient interactions between LC molecules
and pore walls. Using IR spectroscopy, it is shown that the formation of hydrogen bonds between cyano groups of 5CB molecules
and silanol groups of pore surface is the predominant type of these interactions. A transfer mechanism is suggested according
to which excited associates of 5CB molecules transfer their energy via surface channels to excitons of porous silicon, enhancing
its fluorescence. 相似文献
16.
Edward K. G. Sarkisyan Alexander S. Sakharov 《The European Physical Journal C - Particles and Fields》2010,70(3):533-541
The energy-dependence of charged particle mean multiplicity and pseudorapidity density at midrapidity measured in nucleus–nucleus
and (anti)proton–proton collisions are studied in the entire available energy range. The study is performed using a model,
which considers the multiparticle production process according to the dissipating energy of the participants and their types,
namely a combination of the constituent quark picture together with Landau relativistic hydrodynamics. The model reveals interrelations
between the variables under study measured in nucleus–nucleus and nucleon–nucleon collisions. Measurements in nuclear reactions
are shown to be well reproduced by the measurements in pp/[`(p)]p{\bar{\mathrm{p}}}{\mathrm{p}} interactions and the corresponding fits are presented. Different observations in other types of collisions are discussed
in the framework of the proposed model. Predictions are made for measurements at the forthcoming LHC energies. 相似文献
17.
In terms of the adiabatic theory of interactions, we consider the results of the theoretical estimation of the rate constants
K
ST
of the nonradiative intersystem crossing conversion S
1(ππ*) ⇝ T
1
S
(ππ*) for nine aromatic molecules containing 10–14 carbon atoms and one or two heavy (many-electron) oxygen or chlorine atoms. 相似文献
18.
M.G. Ryskin A.D. Martin V.A. Khoze 《The European Physical Journal C - Particles and Fields》2008,54(2):199-217
We present a ‘new generation’ model for high energy proton–proton ‘soft’ interactions. It allows for a full set of multipomeron
vertices as well as for including multichannel eikonal scattering. It describes the behaviour of the proton–proton total,
σtot, and elastic, dσel/dt, cross sections together with those for low- and high-mass proton dissociation. Although the model contains a comprehensive
set of multipomeron diagrams, it has a simple partonic interpretation. Including the more complicated multipomeron vertices
reduces the absorptive effects as compared to the predictions in which only the triple-pomeron vertex is considered. Tuning
the model to describe the available ‘soft’ data in the CERN ISR–tevatron energy range, we predict the total, elastic, single-
and double-diffractive dissociation cross sections at the LHC energy. An inescapable consequence of including multichannel
eikonal and multipomeron effects is that the total cross section is expected to be lower than before: indeed, we find σtot≃ 90 mb at the LHC energy. We also present differential forms of the cross sections. In addition, we calculate soft diffractive
central production. 相似文献
19.
Agarwal S 《Journal of fluorescence》2011,21(5):1959-1967
It has been reported previously that the photophysics of 3-aminoquinoline (3AQ) is governed by a flip–flop motion of its amino
group in apolar solvents and intersystem crossing in polar solvents. The nonradiative rates are governed by more than one
solvent parameters, like polarity and hydrogen bonding ability of the solvent. So, 3AQ is not a well-behaved probe of any
individual solvent parameter. In the present work, 3AQ has been modified synthetically; replacing an amino hydrogen atom with
a methyl group and photophysical properties were studied in 22 different apolar, polar-aprotic and polar-protic solvents.
It is found that Stokes’ shifts and fluorescence quantum yields exceptionally low in apolar solvents as compared to those
in other solvents. Such substitution causes a decrease in the extent of the effect of the hydrogen bonding ability of the
solvent and that nonradiative rate become a more regular function of polarity. However, the flip–flop appears to continue
to be the major nonradiative pathway, as the nonradiative rates decrease with increase in micropolarity. 相似文献
20.
The article considers the luminescence-kinetics properties of crystals of ternary uranyl orthephosphates Me7Eu2UO2(PO4)5 (Me — Na, Rb, Cs) obtained by the methods of solid-phase synthesis. The main parameters of conversion of the electron excitation
energy in the donor-acceptor UO
2
2+
—Ln3+ system are determined. The competition between the processes of nonradiative dissipation and energy transfer from UO
2
2+
to Eu3+ has been revealed. It is shown that the rate of the processes of nonradiative transitions in the uranyl complex is determined
by the degree of distortion of its local field, while the luminescence lifetime of the acceptors depends on the energy of
electrostatic interaction between Eu3+ and oxygen atoms of its first coordination sphere.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 3, pp. 333–335, May–June, 2000. 相似文献