Персона: Лебедев-Степанов, Петр Владимирович
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Институт нанотехнологий в электронике, спинтронике и фотонике
Институт ИНТЭЛ занимается научной деятельностью и подготовкой специалистов в области исследования физических принципов, проектирования и разработки технологий создания компонентной базы электроники гражданского и специального назначения, а также построения современных приборов на её основе.
Наша основная цель – это создание и развитие научно-образовательного центра мирового уровня в области наноструктурных материалов и устройств электроники, спинтроники, фотоники, а также создание эффективной инновационной среды в области СВЧ-электронной и радиационно-стойкой компонентной базы, источников ТГц излучения, ионно-кластерных технологий материалов.
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Петр Владимирович
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- ПубликацияОткрытый доступStructure Visualization of 4-DASPI–Cucurbituril Supramolecular Complex to Predict the Solvatochromic Shift of Absorption Spectrum(НИЯУ МИФИ, 2024) Stepko, A. S.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр ВладимировичThe study of supramolecular “host-guest” complexes in solutions is of fundamental and practical significance. The structures and formation enthalpy of supramolecular complexes for the 4-DASPI dye with two cavitands (cucurbit[6]uril and cucurbit[7]uril) have been obtained by the TDDFT quantum chemistry method with a camb3lyp basis. It was shown by visualization of the structures that the size of cucurbit[6]uril is too small and doesn’t allow the dye chromophore to penetrate into the cavitand cavity while the dye stays in the ground state, but the formation of an external complex is possible. On the contrary, formation of an inclusion complex with the cucurbit[7]uril is energetically favorable, and the dye chromophore penetrates into the cavity. Visualization of the complex structure allows us to determine the chromophore position relative to the given cavitand cavity, and thus we can predict the changes in the dye spectra due to complexation. The theoretical results of the work are in good correlation with the experiment.
- ПубликацияОткрытый доступComputer modeling and simulation of electrically charged nano/micro-particles interaction into aqueous solution by the Brownian dissipative dynamics of their atomic counterions ensemble(2019) Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович© Published under licence by IOP Publishing Ltd. On the basis of free energy functional of charged ions and equation of diffusion of ions in self-consistent electric potential, a method of Brownian dissipative dynamics of ions near electrically charged colloidal micro/nano-particles in aqueous solution or dusty plasma particles in the air is proposed for investigation of ionic atmosphere structure near charged surfaces, and electric interparticle force is calculated.
- ПубликацияОткрытый доступComputation of dielectric properties of nano-probe local surroundings by solvatochromic spectral shift measurement of organic dye molecule(2019) Stepko, A. S.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович© Published under licence by IOP Publishing Ltd. Study of dielectric properties of the macrocyclic molecules cavity that can form inclusion complexes with dye molecules is an important problem. Changes in absorption spectra of chromophore inserted into macrocyclic cavity with the formation of the supramolecular complex can be considered as solvatochromic shift. This shift caused by changes of dielectric properties of the environment around the chromophore when it moves from water solution to macrocyclic cavity. Theoretical model that can describe the effective dielectric permittivity of the cavity allows predicting solvatochromic spectral shift of dye molecules due to non-covalent supramolecular complexation. Such a dye molecule could apply as a nano-probe for measurement of the effective dielectric constant of any local surrounding media in which its chromophore can be inserted.
- ПубликацияОткрытый доступParametric broadening of the molecular vibronic band due to zero-point oscillations and thermal fluctuations of interatomic bonds(2021) Lebedev-Stepanov, P.; Лебедев-Степанов, Петр Владимирович© 2021 Author(s).Numerous computations of the spectra of molecules are performed by mainstream methods based on the fundamental work by Lax [J. Chem. Phys. 20, 1752 (1952)] for smoothing a series of individual transitions represented by delta functions. There is an assumption that the linewidth of an individual rovibronic transition spectrum is many orders of magnitude smaller than the rovibronic bandwidth. However, the presence of rotational-vibrational structure in the molecular spectrum masks the broadening of each individual rovibronic transition. In this work, in the framework of harmonic approximation of potential energy surfaces, a new kind of contribution to homogenous broadening is considered to describe the optical spectrum of any single rovibronic transition. Its origin is in zero-point oscillations and thermal fluctuations around equilibrium positions of nuclei. Franck-Condon diagrams with slanting equidistant vibrational levels are proposed. Expressions of the spectral intensity of a single vibronic transition are derived from the first principles. This theory was used to estimate the broadening magnitude of the vibronic transition due to quantum uncertainty of nuclear coordinates of linear polymethine dyes with an extended π-electron system. It was shown that the calculated magnitude of the broadening is approximately two times smaller than the bandwidth observed in the experiment but it has the same order of magnitude. The value of such broadening depends on the environment that restricts the vibrational and rotational degrees of freedom of the molecule. It was demonstrated that an organic chromophore with an extended π-electron system can be considered to be a molecular optical parametric oscillator.
- ПубликацияОткрытый доступSlow evaporation of a small sessile liquid drop: New solutions based on the electrostatic analogy(2024) Lebedev-Stepanov, P.; Лебедев-Степанов, Петр ВладимировичAbstract Evaporating sessile drop of liquid deposited on horizontal surface is an important object of applications and theoretical investigations. The evaporating flow density dramatically depends on contact angle of the droplet. Previously, the dependence of the flux density on the polar angle was established for arbitrary contact angles. The expression has the form of an integral and is rather complicated for use in modelling algorithms. In this paper, we propose new exact solutions for the set of some specific contact angles (135-180 degrees). The analogy of the drop evaporation problem with a similar problem from the field of electrostatics of equipotential surfaces, which has been solved in general terms before us, was used. The results of British mathematician H.M. Macdonald and Soviet scientist G.A. Grinberg were used in the derivation. Thus, relatively simple expressions for the evaporation flux density were found.
- ПубликацияОткрытый доступEstimation the dielectric properties of solvation shells and nano-cavities by solvatochromic shift of organic dye(2021) Stepko, A. S.; Savenko, O. A.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр Владимирович© Published under licence by IOP Publishing Ltd.We investigated the preferential solvation effect of pyridinium-N-phenolate betaine (organic dye) taken as a molecular probe in two binary solvents (water-BuOH and water-BuNH2) in concentration range 0-100%. The Onsager-Liptay model was used to connect the spectral solvatochromic shift in solvation shell of the dye with the dielectric permittivity of the environment around its chromophore. That makes it possible to estimate the effective dielectric constant in the microscopic region of the probe, based on the values of the experimentally measured solvatochromic shifts. It was shown that the solvation shell of the dye is significantly depleted with the second component of binary solvent in water solution. It is true both for the water-BuOH and water-BuNH2 solvents. The absolute spectral shift in case of water-BuNH2 solvent is greater than in the second case. However, the relative depletion is stronger in case of water-BuOH. The innovative potential of the method is in the development the nanoprobe devices to measure the dielectric constant of small objects and nano-regions, to control instantaneous solvent concentration into evaporating sessile droplet of binary solvent in different zones of the droplet.
- ПубликацияОткрытый доступStructure Visualization of 4-DASPI–Cucurbituril Supramolecular Complex to Predict the Solvatochromic Shift of Absorption Spectrum(2024) Stepko, A. S.; Lebedev-Stepanov, P. V.; Лебедев-Степанов, Петр ВладимировичThe study of supramolecular ў??host-guestў?? complexes in solutions is of fundamental and practical significance. The structures and formation enthalpy of supramolecular complexes for the 4-DASPI dye with two cavitands (cucurbit[6]uril and cucurbit[7]uril) have been obtained by the TDDFT quantum chemistry method with a camb3lyp basis. It was shown by visualization of the structures that the size of cucurbit[6]uril is too small and doesnў??t allow the dye chromophore to penetrate into the cavitand cavity while the dye stays in the ground state, but the formation of an external complex is possible. On the contrary, formation of an inclusion complex with the cucurbit[7]uril is energetically favorable, and the dye chromophore penetrates into the cavity. Visualization of the complex structure allows us to determine the chromophore position relative to the given cavitand cavity, and thus we can predict the changes in the dye spectra due to complexation. The theoretical results of the work are in good correlation with the experiment.