K. M. Salikhov

Russian Academy of Sciences, Moskva, Moscow, Russia

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Publications (121)114.44 Total impact

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    ABSTRACT: The energy transfer mechanism, which provides the feeding of the excited 5D4 level of Tb(III), has been studied by photoluminescence spectroscopy in the Tb(III) complex with p-sulfonato-thiacalix[4]arene doped into the silica nanoparticles. The quantitative evaluation of the rate constants of each energy transfer step highlights two channels of the energy transfer from the singlet ligand-centered level to the 5D4 level. The channel one occurs via the triplet ligand level S1→T1→5D4, the second channel comes about via the higher levels of Tb(III) S1→5D3→5D4. The latter channel determines the rate of the luminescence decay of the 5D4 level. The high luminescence efficiency and enhanced thermo- and photo-stabilities make the Tb(III) complexes doped into the silica nanoparticles a promising nanomaterial for medical and bioanalytical applications.
    Journal of Luminescence 01/2015; 157:158–162. · 2.14 Impact Factor
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    ABSTRACT: The study of the terbium(III) and gadolinium(III) βdiketonate complexes by photoluminescence spectroscopy reveals considerable changes of the photophysical properties of the complexes under UV laser irradiation. The measurements show the enhancement of the luminescence intensities in the vitrified transparent film of the terbium(III) complex as well as the gadolinium(III) complex under the 337 nm laser irradiation at room temperature. The irradiated film of the terbium(III) complex restores the initial photophysical properties after heating close to the melting temperature (~353 K) and cooling. We did not observe any change of the luminescent properties of the irradiated film for months. These features can be used for the design of new lanthanide-based photostable systems with laser control of the luminescence intensity.
    Optical Materials 09/2014; · 2.08 Impact Factor
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    ABSTRACT: Electron Paramagnetic Resonance (EPR) spectra of the nitroxide spin probe 3β-doxyl-5α-cholestane (CSL) are studied as functions of the molar concentration, c, and the temperature, T, in a series of n-alkanes. The results are compared with a similar study of a much smaller spin probe, perdeuterated 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl (pDT). The Heisenburg spin exchange (HSE) rate constants, K(ex) , of CSL are similar in hexane, octane and decane, and are about one-half of those for pDT in the same solvents. They are also about one-half of the Stokes-Einstein-Perrin (SEP) prediction. This reduction in HSE efficiency is attributed to an effective steric factor, f(eff) , which was evaluated by comparing the results with the Stokes-Einstein-Perrin prediction or with pDT is f(eff) = 0.49 ± 0.03, independent of temperature. The unpaired spin density in CSL is localized near one end of the long molecule, so the exchange integral, J , leading to HSE, is expected to be large in some collisions and small in others; thus, J is modeled by an ideal distribution of values of J =J(0) with probability f and J = zero with probability (1-f). Due to rotational and translation diffusion during contact and between re-encounters of the probe, the effective steric factor is predicted to be f(eff) = f(1/2) . Estimating the fraction of the surface of CSL with rich spin density, yields a theoretical estimate of f(eff) = 0.59 ± 0.08, in satisfactory agreement with experiment. HSE is well described by simple hydrodynamic theory, with only a small dependence on solvent-probe relative sizes at the same value of T/η, where η is the viscosity of the solvent. This result is probably due to a fortuitous interplay between long- and short-range effects that describe diffusion processes over relatively large distances. In contrast, dipole-dipole interactions (DD) as measured by the line broadening, B(dip) , and the mean time between re-encounters within the cage, τ(RE), vary significantly with the solvent-probe size ratio at the same value of T/η. For these phenomena, dominated by short-range diffusion, the reciprocal fractional free volume ,V(0)/V(f) provides a better description of the diffusion. Thus B(dip) and τ(RE) form common curves when plotted vs. V(0)/V(f). As a result, the fractional broadening by DD occurs at an order of magnitude higher values of T/η for CSL compared with pDT.
    The Journal of Physical Chemistry A 11/2012; · 2.77 Impact Factor
  • K. M. Salikhov
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    ABSTRACT: This report presents a comprehensive analysis of the contributions of the Heisenberg exchange and dipole–dipole interactions in diluted solutions of nitroxide radicals to the shape of their electron paramagnetic resonance (EPR) spectra taking into account all coherence transfer processes. It is shown that these contributions interfere. The approaches to obtain the molecular-kinetic and exchange integral parameters by analyzing the EPR spectrum dependence on the radical concentration and the solvent viscosity are discussed.
    Applied Magnetic Resonance 01/2010; 38(2):237-256. · 0.83 Impact Factor
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    ABSTRACT: The phase behavior of a self-organizing system based on the nonionic surfactant of decaethylene glycol monodecyl ether-lanthanum nitrate hexahydrate-water and decanol is presented. A system phase diagram was constructed. The concentration, temperature ranges of existence and types of liquid crystal phases were established. Analysis of structural changes during the phase transitions hexagonal phase-lamellar phase-isotropic liquid was made on the basis of data obtained by viscosimetry and self-diffusion NMR.
    Russian Journal of Physical Chemistry 01/2010; 84(5):802-807. · 0.49 Impact Factor
  • Yuri E. Kandrashkin, Kev M. Salikhov
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    ABSTRACT: Quantum teleportation of electron spins in the modified photosynthetic reaction centers is investigated numerically. The output of the teleported state is analyzed as a signal of the primary spin echo. The simulations of the model systems clarifying the role of different contributions to the signal are described. Requirements for the successful teleportation, including the recombination rates, Zeeman and spin–spin interactions are found. The variation of the teleportation scheme is discussed.
    Applied Magnetic Resonance 01/2010; 37(1):549-566. · 0.83 Impact Factor
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    Klaus Möbius, Kev M. Salikhov
    Applied Magnetic Resonance 01/2010; 37(1):1-4. · 0.83 Impact Factor
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    ABSTRACT: The results of the femtosecond four-wave mixingmeasurements performed on the CdS crystal at room temperature are reported. The dephasing time Td = 180 fs was obtained. The anti-Stokes shift of the primary photon echo spectrum with respect to the excitation spectrum was observed. The some peculiarities of the coherent responses decay curves indicate that this optical dephasing is due to the exciton-exciton interaction. The stimulated photon echo decay curves appear to have a fast decay component (the time constant of approximately 4.5 ps) in case the energy of exciting pulses exceeds the threshold value of 0.4 μ J. (© 2009 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 06/2009; 6(9):644 - 646. · 2.96 Impact Factor
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    R. B. Zaripov, R. M. Aminova, K. M. Salikhov
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    ABSTRACT: Manifestations of the hyperfine interaction of paramagnetic particles in their electron spin echo signal decay were comprehensively discussed. Mechanochemically activated calcium gluconate was studied using electron spin echo modulation phenomenon and electron-nuclear double resonance techniques and quantum-chemical calculations. Three possible structures are obtained for free radicals in calcium gluconate. To specify the structure of radicals, further investigations are needed.
    Applied Magnetic Resonance 01/2009; 35(2):337-358. · 0.83 Impact Factor
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    ABSTRACT: Electron paramagnetic resonance (EPR) spectra of the spin-correlated charge-separated states in photosynthetic reaction centers were numerically simulated with the unresolved hyperfine structure of the EPR lines treated, for the first time exactly, by the Monte Carlo method. The parallel computers with distributed-memory-oriented program tools were elaborated to implement these calculations. The results obtained were compared with those for the unresolved hyperfine structure of the EPR lines taken into account in the framework of a conventional approximate description (the convolution method). It is shown that both approaches lead to practically the same transient EPR spectral shapes in W- and Q-bands, while in the X-band they lead to a noticeably different spectrum shape. Our results show that the shape of the EPR spectra detected at the magnetic fields around 300 mT (X-band EPR) can be simulated well only by the Monte Carlo method, while at higher magnetic fields (Q- and W-bands) the experimental EPR spectra can be simulated reasonably well by the convolution approximation.
    Applied Magnetic Resonance 11/2008; 35(1):113-125. · 0.83 Impact Factor
  • A. A. Obynochnyi, P. A. Purtov, K. M. Salikhov
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    ABSTRACT: Chemical nuclear polarization (CNP) of short-lived biradicals created in the photolysis of cyclic ketones in the gas phase with a buffer gas of CDCl3 molecules was studied theoretically and experimentally. The magnetoresonance and kinetic parameters were proposed for the biradicals. The experimental fact that the CNP of cycloundecanone in the gas phase and liquid was the strongest was confirmed by calculations. The computational results agree well with the experiment for both gas and liquid phases.
    Russian Journal of Physical Chemistry 01/2008; 82(2):298-302. · 0.49 Impact Factor
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    ABSTRACT: Some results of femtosecond echo experiments on polyvinylbutyral polymer films doped with phtalocyanine molecules at high (up to room) temperatures are reported. Special attention is paid to the stimulated femtosecond photon echo (SFPE), which was observed in a solid-state medium at room temperature for the first time. A decay curve of the SFPE signal has been obtained and theoretically analyzed. The results of the analysis indicate that the random interaction between impurity molecules and quasi-localized low-frequency vibration modes in an amorphous matrix plays the dominant role in the character of optical dephasing at high temperatures.
    Bulletin of the Russian Academy of Sciences Physics 01/2008; 72(7):1019-1021.
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    ABSTRACT: The structural analog of liquid-crystalline adducts of lanthanides containing nitroxyl radicals in the bipyridine moiety was synthesized. The distances between the radicals in the ligand and adduct were determined by the pulse ESR technique. The obtained data were used as a criterion for the adequate choice of the parameters of the semiempirical quantum chemical calculation of the structures of the LnIII coordination compounds containing paramagnetic centers.
    Russian Chemical Bulletin 01/2008; 57(7):1564-1567. · 0.42 Impact Factor
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    ABSTRACT: The absorption and emission spectra of a liquid-crystalline melt prepared on the basis of a synthesized mesogenic europium (III) adduct are studied in the temperature range from 77 to 348 K. The main channels and rate constants of intramolecular energy transfer from ligands to Eu (III) ions are determined from the absorption and luminescence spectra and luminescence kinetics of the sample under study. It is shown that the liquid-crystalline melt of the europium (III) adduct has a high photostability and an intense luminescence in the temperature range from 77 to 300 K, which allows one to consider it as a promising material for optoelectronic devices. Above room temperature, the relaxation time of the 5 D 0 level of Eu (III) ions sharply shortens. An analysis of the kinetics of the luminescence corresponding to the 5 D 0 → 7 F 2 transition shows that the relaxation of the 5 D 0 level in the temperature range from 300 to 348 K occurs through a charge-transfer state.
    Optics and Spectroscopy 01/2008; 104(6):851-857. · 0.56 Impact Factor
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    ABSTRACT: In previous papers by the third author, a mechanism of the electron spin polarization of excited triplet states caused by mutual annihilation of triplet states was forecasted and experimentally recognized. Here, a qualitative theory of the mechanism of polarization for triplet excitons in molecular crystals is developed. For solution of the boundary problem the implicit difference scheme is used and for solution of the kinetic equation the Runge-Kutta scheme of the 4-th order is applied.
    Matematicheskoe Modelirovanie. 01/2008; 20(12).
  • K. M. Salikhov, J. H. Golbeck, D. Stehlik
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    ABSTRACT: In the process coined quantum teleportation the complete information contained in an input quantum stateΨ i is teleported to a distant location at which the original quantum state is regenerated as teleported output stateΨ i. This paper presents the proof-of-feasibility concept of a quantum teleportation experiment during which an arbitrary input quantum state is teleported across a biological membrane. As particular aspect it is emphasized that all essential subprocesses of the usual quantum teleportation scheme are suggested to be realized by free running reaction processes in a biological membrane-bound reaction center complex with only one significant adaptation required at the input side. The first process of generation of a spin-correlated (Einstein-Podolsky-Rosen) pair of particles (Bell-state source) is a naturally occurring process realized in photosynthetic reaction centers by the primary processes of light-induced charge separation across the membrane. The second process is the so-called Bell-state measurement, which is able to store the complete information of the input quantum state. It is suggested to be realized by a fast spin-dependent recombination between one pair partner spin and a properly engineered input spin. Under suitable recombination conditions the remaining second pair partner spin, situated at the receiver location on the other side of the membrane, is shown to end up in the quantum state identical to that of the initial input state due to the fixed spin correlation of the Bell-state source and the particular spin selectivity of the recombination process. Thus, the input (spin) quantum state is teleported from the spin near the (electron charge) donor side to the acceptor side of the membrane-bound photosynthetic reaction center complex. A comprehensive discussion is presented for this quantum teleportation concept using photosynthetic reaction centers as the quantum channel of communication. Standard electron paramagnetic resonance techniques can be used to set up the input state and read out or hand over the output state for subsequent quantum information processing.
    Applied Magnetic Resonance 01/2007; 31(1):237-252. · 0.83 Impact Factor
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    ABSTRACT: In this work, detailed analysis of two-pulse photon echo (2PPE) generation in thin dye-doped polyvinylbutural films in large temperature interval (from liquid helium temperature to room temperature) is presented. The focus of the study is on the non-collinear scheme of echo-hologram recording and analysis of the temporal behavior of the echo-signals as well as their spectrum in dependence on the angle beta between the wave vectors of the excitation pulses. The distinguishing feature of polymer films is their extremely large inhomogeneous width of spectral line. As follows from a phase matching condition with increasing beta the 2PPE signal frequency shifts to blue spectral range in relation to the central frequency of transition even if the exciting pulses are in resonance. The more the angle beta, the larger the blue shift.
    01/2007;
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    ABSTRACT: The signals of primary and stimulated femtosecond photon echoes are investigated in a dye-doped polymer film at room temperature. The homogeneous S 0 → S 1 spectral line width, which is due to the interaction between the impurity molecules and the quasi-local low-frequency modes, is estimated (≈5 × 1012 Hz). Special attention is paid to the study of spectra of femtosecond echo signals. The short-wave shifts of these spectra, with respect to the spectrum of femtosecond exciting pulses, are observed. These shifts indicate that the anti-Stokes regime of femtosecond pulse emission is realized. Therefore, the coherent regime of laser cooling of solids appears to be possible. The prospects of using of this new cooling regime in the function of a solid-state optical refrigerator are discussed.
    Laser Physics 01/2007; 17(5):647-651. · 1.03 Impact Factor
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    ABSTRACT: The signals of both primary and stimulated femtosecond photon echoes are observed and investigated in a dye-doped polymer film at room temperature using a modernized femtosecond echo-spectrometer. It should be noted that stimulated photon echo in the solid-state sample is observed for the first time at such a high temperature. Experimentally obtained decay curves of these signals have a nonexponential character. The spectra of these echo signals are also measured. It is found that the spectrum of the primary photon echo is short-wave shifted with respect to the spectrum of excitation. This can be used for the coherent laser cooling of a sample. The spectrum of the stimulated photon echo is also shifted to the short-wave range relative to the spectrum of excitation, but its shift is much less than that of the primary photon echo. The experiment shows that the femtosecond echo signals at room temperature are excited via the phonon-side band of the absorption line.
    Laser Physics 01/2007; 17(4):332-338. · 1.03 Impact Factor
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    ABSTRACT: It is reported about the first observation (in a solidstate sample) and detailed investigation of the stimulated femtosecond photon echo (SFPE) signals at room temperature in a polyvinylbutural film doped with molecules of phthalocyanine of HW 1009 type at the wavelength of 788 nm. A dependence of relative intensity of these echo-signals on time intervals between the second and the third exciting pulses was studied and the SFPE spectrum was investigated with respect to the spectra of both exciting pulses and signals of self-diffraction. It was found that the linear electron-phonon coupling is weak and the influence of the phonon-side band of the absorption line on the SFPE signals is less significantly than on the signals of primary photon echo. (© 2006 by Astro, Ltd. Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)
    Laser Physics Letters 06/2006; 3(10):485 - 489. · 2.96 Impact Factor

Publication Stats

419 Citations
114.44 Total Impact Points

Institutions

  • 1971–2012
    • Russian Academy of Sciences
      • • Institute of Chemical Kinetics and Combustion
      • • Zavoisky Physical-Technical Institute, Kazan Branch
      Moskva, Moscow, Russia
  • 1998
    • Freie Universität Berlin
      • Institute of Experimental Physics
      Berlin, Land Berlin, Germany
  • 1987
    • Kemerovo Institute of Food Science and Technology
      Shcheglovsk, Kemerovo, Russia
  • 1983–1984
    • Novosibirsk State University
      Novo-Nikolaevsk, Novosibirsk, Russia
  • 1982
    • Altai Mir University
      Altayskiy, Altayskiy, Russia