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1.
Electronic-excitation energy transfer between molecules of Coumarin 7 (donor) and Rhodamine B (acceptor) have been experimentally investigated in one-dimensional photonic crystals based on oxidized mesoporous silicon and in a similar matrix, which does not possess the properties of a photonic crystal. The efficiencies of excitation transfer between donor and acceptor molecules have been determined based on the donor-fluorescence quenching and sensitized acceptor luminescence. It is established that the efficiency of electronic-excitation energy transfer in a photonic crystal increases in comparison with that for porous silicon. 相似文献
2.
Nonradiative triplet-singlet transfer of electronic-excitation energy between molecules of organic dyes (erythrosine and methylene blue) in a polymer film that is deposited on the surface of a silver layer is experimentally studied. It is demonstrated that the energy-transfer efficiency in such a system is lower than the efficiency in the samples without metal layers. The results of the proposed mathematical model are in qualitative agreement with the experimental data. 相似文献
3.
Nonradiative electron excitation energy transfer between the molecules adsorbed by the plane conducting surface is investigated.
It is demonstrated that the mechanism with participation of surface plasmons can be efficient for energy transfer in such
system. A dependence of the energy transfer rate in the donor-acceptor adsorbate pair on the distance and anisotropy parameters
is established. The efficiencies of the direct dipoledipole and plasmon channels of energy transfer are compared. The dominating
(exceeding by 1–2 orders of magnitude the energy transfer rate in a system without conducting bodies) contribution of the
plasmon mechanism to the total energy transfer rate is detected when molecules are close to the metal surface. 相似文献
4.
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
5.
6.
The processes of electronic excitation energy transfer (EEET) between different types of dye molecules inserted into the matrix
of a porous glass have been investigated. An extreme character of the dependence of the EEET efficiency on the size of pores
has been revealed. The dependence of the fractal dimensionality of the distribution of dye molecules on the sizes of the pores
has been determined.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 72, No. 4, pp. 446–449, July–August, 2005. 相似文献
7.
The specific features of the triplet-triplet (T-T) transfer of electronic excitation energy in a gas phase upon nonequilibrium
vibrational excitation of the triplet molecules of a donor were studied for an anthraquinone-diacetyl donor-acceptor pair
using the time-resolved slow fluoresence of anthraquinone and sensitized phosphorescence of diacetyl. It is shown that in
the gas phase, which allows regular control of the number of collisions, competition between the processes of T-T transfer
and intermolecular vibrational relaxation is observed for nanosecond time resolution. The T-T transfer rate for the molecular
system investigated exceeded the rate of intermolecular vibrational relaxation kV in the triplet state T1 of the donor. The effectiveness of the T-T transfer of energy by vibrationally excited molecules turned out to be higher
than the effectiveness of transfer by thermalized ones, but even the highest of them was much less than unity. An increase
in the equilibrium temperature of vapors led to a decrease in the effectiveness of transfer for both vibrationally excited
and thermalized triplet molecules, thus indicating the importance of the collisional complex in the intermolecular process
studied.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 4, pp. 474–479, July–August, 2000. 相似文献
8.
We have studied the mechanisms for quenching of the fluorescence of conjugated poly(p-phenylene) polymers by benzil and dimethylaminobenzil
molecules. We have shown that molecules in the diketone series are quenching agents for the fluorescence of the indicated
polymers, and can serve as singlet-triplet converters capable of populating the triplet state of the polymer. We have observed
that the efficiency of quenching of the fluorescence of the studied polymers depends considerably on the presence of bulky
side groups in the polymer or in the activator molecules. Based on analysis of the data obtained, we conclude that in the
case of a rigid planar structure for the polymer, a significant contribution to quenching of its fluorescence comes from not
only singlet-singlet energy transfer but also charge transfer, leading to formation of intermolecular complexes (exciplexes).
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 6, pp. 756–762, November–December, 2006. 相似文献
9.
J. Franz F. A. Gianturco 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(3):407-413
Vibrationally inelastic quantum calculations are carried
out at low collision energies for the scattering of a beam of
positrons off acetylene gaseous molecules. The normal mode analysis
is assumed to be valid and the relative fluxes into the C–C and C–H
symmetric vibrational modes are computed within a Body-Fixed (BF)
formulation of the dynamics by solving the relevant vibrational
Coupled Channels (VCC) equations. The clear dominance of the C–C
mode is observed near threshold and the implications of this finding
are briefly considered in relation to more global indicators like
the average vibrational energy transfer indices as obtained in the
present work. 相似文献
10.
V. A. Tolkachev 《Journal of Applied Spectroscopy》1998,65(5):643-658
A number of phenomena that determine the nature of the fluorescence of free complex molecules and the possibility of its analytical
application are considered. Attention is specially paid to the specific features of the energetics of radiationless transitions,
the role of statistical factors in the formation of spectral properties and the interrelationship among the luminescence-spectrum
characteristics of rarefied vapors of complicated molecules, and the processes of energy transfer in collisions. The properties
of polarized fluorescence of hot and jet-cooled vapors, the processes of relaxation of anisotropy in time and during collision
reorientation, and transfer of anisotropy in photodisintegration are analyzed.
Institute of Molecular and Atomic Physics, National Academy of Sciences of Belarus, 70, F. Skorina Ave., Minsk, 220072, Belarus.
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 65, No. 5, pp. 620–634, September–October, 1998. 相似文献
11.
We have studied the characteristic features of carbazole phosphorescence quenching by benzophenone in toluene at 77 K. We
have shown that the decrease in the relative phosphorescence intensity for carbazole (energy donor) by a greater factor than
we see for the relative change in its decay time is due to the fact that a change in the phosphorescence decay time occurs
only for carbazole molecules participating in triplet-triplet energy transfer, while the substantial decrease in the phosphorescence
intensity for carbazole with no change in the phosphorescence decay time is connected with quenching of its singlet states.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 554–556, July–August, 2006. 相似文献
12.
I. N. Ogorodnikov N. E. Poryvai I. N. Sedunova A. V. Tolmachev R. P. Yavetskiy 《Optics and Spectroscopy》2011,110(2):266-276
The luminescence and thermally stimulated recombination processes in lithium borate crystals Li6Gd(BO3)3 and Li6Gd(BO3)3:Ce have been studied. The steady-state luminescence spectra under X-ray excitation (X-ray luminescence), temperature dependences
of the intensity of steady-state X-ray luminescence (XL), and thermally stimulated luminescence (TSL) spectra of these compounds
have been investigated in the temperature range of 90–500 K. The intrinsic-luminescence 312-nm band, which is due to the 6
P
J
→ 8
S
7/2 transitions in Gd3+ matrix ions, dominates in the X-ray luminescence spectra of these crystals; in addition, there is a wide complex band at
400–420 nm, which is due to the d → f transitions in Ce3+ impurity ions. It is found that the steady-state XL intensity in these bands increases several times upon heating from 100
to 400 K. The possible mechanisms of the observed temperature dependence of the steady-state XL intensity and their correlation
with the features of electronic-excitation energy transfer in these crystals are discussed. The main complex TSL peak at 110–160
K and a number of minor peaks, whose composition and structure depend on the crystal type, have been found in all crystals
studied. The nature of the shallow traps that are responsible for TSL at temperatures below room temperature and their relation
with defects in the lithium cation sublattice are discussed. 相似文献
13.
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
14.
O. V. Ovchinnikov E. A. Kosyakova M. S. Smirnov A. B. Evlev V. G. Klyuev A. N. Latyshev A. N. Utekhin 《Journal of Applied Spectroscopy》2007,74(5):681-686
For microcrystals of Zn0.6Cd0.4S with adsorbed molecules of a number of organic dyes, we have observed sensitized anti-Stokes luminescence excited by radiation
with wavelengths in the range 610–750 nm and flux density 1014–1015 photons/cm2·sec. The positions of the bands in the excitation spectra for such luminescence match those of the absorption spectra for
the adsorbed dye molecules, which is evidence in favor of a cooperative mechanism for its appearance. We have shown that enhancement
of the anti-Stokes luminescence is possible when silver atoms and few-atom clusters appear on the Zn0.6Cd0.4S surface in addition to the dye molecules. We hypothesize that its excitation in the latter case occurs as a result of two-photon
optical transitions. These transitions occur sequentially, with transfer of an electron or the electronic excitation energy
from the dye molecules to silver atoms and few-atom clusters adsorbed on the surface of Zn0.6Cd0.4S, creating deep localized states in the bandgap with photoionization energies 1.80–2.00 eV.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 74, No. 5, pp. 617–621, September–October, 2007. 相似文献
15.
K. Saito M. Kato H. Yajima M. Kimura T. Uchiyama 《Applied physics. B, Lasers and optics》2007,87(1):105-110
The third order nonlinear optical properties of 4′-methoxy chalcone and its derivatives have been investigated using a single-beam Z-scan technique with nanosecond laser pulses
at 532 nm. The 4′-methoxy chalcone and its derivatives are donor–acceptor–acceptor (D–A–A) and donor–acceptor–donor (D–A–D) type intramolecular
charge transfer molecules. The nonlinear response in these molecules was found to increase with increase in (a) the electron
acceptor strength in D–A–A type and (b) the donor strength of the substituted group in D–A–D type molecules. The χ(3) value in these molecules is found to be of the order of 10-13 esu. The observed increase in the third order nonlinearity in these molecules clearly indicates the electronic origin. The
compounds exhibit good optical limiting at 532 nm. The best optical limiting behavior was observed with the molecule substituted
by a strong electron donor.
PACS 42.65.An; 42.70.Nq 相似文献
16.
Atul D. Sontakke Kaushik Biswas Ashis K. Mandal Kalyandurg Annapurna 《Journal of fluorescence》2010,20(1):425-434
This paper reports on the preparation and systematic analysis of energy transfer mechanisms in Nd3+–Yb3+–Er3+ co-doped new series of barium-alumino-metaphosphate glasses. The time resolved fluorescence of Nd3+ in triply doped Ba–Al-metaphosphate glasses have revealed that, Yb3+ ions could function as quite efficient bridge for an energy transfer between Nd3+ and Er3+ ions. As a result, a fourfold emission enhancement at 1.54 μm of Er3+ ions has been achieved through an excitation of 4F5/2 level of Nd3+ at 806 nm for the glass having 3 mol% Yb3+ with an energy transfer efficiency reaching up to 94%. Decay of donor (Nd3+) ion fluorescence has been analyzed based on theoretical models such as direct energy transfer model (Inokuti–Hirayama) and
migration assisted energy transfer models (Burshtein’s hopping and Yokota–Tanimoto’s diffusion). The corresponding energy
transfer parameters have been evaluated and discussed. Primarily, electrostatic dipole–dipole (s ~ 6) interactions are found
to be responsible for the occurrence of energy transfer process in theses glasses. 相似文献
17.
We carry out an analysis of the characteristics of nonlinear luminescence of a multicomponent layer system consisting of layers
of molecules of a sensitizer, donor, and acceptor with inductive-resonance transfer of energy between the components of the
molecular ensemble. We show that in a stationary regime bistable dependences of the populations of excited states of molecules
on excitation intensity are realized without external feedback. For pulse pumping, we show the possibility for forming response-luminescence
pulses with widely variable characteristics: shape, duration, intensity, and delay.
Belorussian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii,
Vol. 66, No. 2, pp. 190–196, March–April, 1999. 相似文献
18.
The kinetics of fluorescence polarization in intense pulse excitation of solid disordered solutions of bichromophores that
consist of complex molecules of two types between which there can be inductiveresonance transfer of electron-excitation energy
is theoretically investigated. Variants of fluorescence excitation by single pulses and pulse trains are considered. The lifetime
of the fluorescence of a given solution increases with the intensity of the exciting pulses. The possibility of controlling
the duration of fluorescence attenuation for donor molecules incorporated into the bichromophores by the action of luminescence
radiation at the frequency of acceptor-molecule absorption on the solution is demonstrated.
Belarusian State University, 4, F. Skorina Ave., Minsk, 220050, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii
Vol. 65, No. 4, pp. 546–550, July–August, 1998. 相似文献
19.
A. A. Gorbatenko V. I. Beketov R. D. Voronina D. A. Zhuravlev O. R. Lyubomirova D. G. Filatova E. I. Revina 《Journal of Applied Spectroscopy》2006,73(4):613-615
Laser-induced ionization spectra of PrO, TbO, and CeO molecules in a flame were recorded in the wavelength ranges 440–480
nm and 535–575 nm. Based on study of the spectra, we propose a two-step scheme for excitation of PrO and CeO molecules in
which in the first step, the molecule goes to the excited electronic state, while the excitation energy in the second step
is selected so that the total energy imparted to the molecule corresponds to its ionization potential.
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Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 73, No. 4, pp. 544–546, July–August, 2006. 相似文献
20.
The architecture and operation of a trace hydrogen cyanide (HCN) gas sensor based on quartz-enhanced photoacoustic spectroscopy and using a λ=1.53 μm telecommunication diode laser are described. The influence of humidity content in the analyzed gas on the sensor performance is investigated. A kinetic model describing the vibrational to translational (V–T) energy transfer following the laser excitation of a HCN molecule is developed. Based on this model and the experimental data, the V–T relaxation time of HCN was found to be (1.91±0.07)10-3 s Torr in collisions with N2 molecules and (2.1±0.2)10-6 s Torr in collisions with H2O molecules. The noise-equivalent concentration of HCN in air at normal indoor conditions was determined to be at the 155-ppbv level with a 1-s sensor time constant. PACS 82.80.Kq; 42.62.Fi 相似文献