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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Лебедев-Степанов
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Петр Владимирович
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- ПубликацияТолько метаданныеSelf-Assembly of Fluorescent Photonic Crystal Structures in Binary Water-Glycerol Solvent Droplets(2020) Savenko, O. A.; Stepko, A. S.; Shevchenko, N. N.; Koshkin, A. V.; Lebedev-Stepanov, P.; Лебедев-Степанов, Петр ВладимировичThe morphology of photonic-crystal structures formed by the self-assembly of fluorescent marker nanoparticles from evaporating droplets of a binary water-glycerol solvent, the components of which differ appreciably from each other in the viscosity and evaporation rate, being infinitely mutually soluble under normal conditions, was has been studied experimentally for the first time. It has been shown that the main self-assembly disordering factor is Marangoni vortex flows, and the change in the initial concentration ratio between binary mixture components enables the control over the degree of disordering in the solid phase, which is formed after the solvent is evaporated from a droplet and distributed over the substrate. A low initial concentration of any component corresponds to the most ordered distribution, whereas their medium concentrations correspond to the most disordered distribution. The characteristic values of Marangoni numbers in experiments have been calculated. It has been demonstrated that the average radius of the distribution of an ensemble of marker particles over a substrate may serve as a descriptor for the degree of ordering.
- ПубликацияТолько метаданныеComputation the effective dielectric constant of nano-probe local surrounding by solvatochromic spectral shift measurement of organic dye molecule(2019) Stepko, A.; Lebedev-Stepanov, P.; Лебедев-Степанов, Петр Владимирович© 2019 IEEE.Computer modeling the dielectric properties of the cucurbit [7]uril (CB [7]) cavity based on the Onsager-Liptay model was carried out by analyzing the solvatochromic shift of the absorption spectrum of 1-(3ammoniumpropyl) -4-[(E) -2-(3,4-dimethoxyphenyl) ethynyl]pyridinium upon the formation of the inclusion complex with CB [7] in a water solution. The CB [7] cavity was considered as a polar environment into which the dye chromophore is placed. Positions of the maxima of the dye absorption spectra were measured experimentally in the following solvents: methanol, ethanol, i-propanol, n-butanol and water with known dielectric and optical properties. These values were used for parametrization of the Onsager-Liptay equation. Quantum-chemical calculations were used to determine molecular structures, dipole moments of the ground and excited states, and polarizability of the dye. Theoretical value of the effective dielectric permittivity of the cavity is in good agreement with the literature data derived by another method. Thus, we propose a new method for investigation the dielectric constant both in bulk liquids and in very small liquid volumes, for example, into picoliter droplets.
- 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.