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Lifetimes of confined optical phonons and the shape of a Raman peak in disordered nanoparticles. I. Analytical treatment
Physical Review B: Condensed Matter and Materials Physics. 2020. Vol. 102. No. 20. P. 205421.
Oleg I. Utesov, Yashenkin A., Koniakhin S.
Microscopic description of Raman spectra in nanopowders of nonpolar crystals is accomplished by developing
the theory of disorder-induced broadening of optical vibrational eigenmodes. Analytical treatment of this
problem is performed, and line shape and width are determined as functions of phonon quantum numbers,
nanoparticle shape, size, and the strength of disorder. The results are found to be strongly dependent on whether
the broadened line is separated from or overlaps other lines of the spectrum. Three models of disorder, i.e., weak
pointlike impurities, weak smooth random potential, and strong rare impurities, are investigated in detail. The
possibility of forming the phonon-impurity bound state is also studied.
Koniakhin S., Oleg I. Utesov, Yashenkin A., Physical Review B: Condensed Matter and Materials Physics 2020 Vol. 102 No. 20 P. 205422
Disorder-induced broadening of optical vibrational eigenmodes in nanoparticles of nonpolar crystals is studied
numerically. The methods previously used to treat the phonons in defectless particles are adjusted for numerical
evaluation of the disordered problem. Imperfections in the forms of Gaussian and binary disorders as well
as surface irregularities are investigated thoroughly in a wide range of impurity concentrations ...
Added: January 14, 2021
Utesov O., Koniakhin S., Yashenkin A., Journal of Physical Chemistry C 2021 Vol. 125 No. 33 P. 18444-18455
Optical phonons in nanoparticles with randomness of interatomic bonds are considered both analytically and numerically. For weak dilute disorder, two qualitatively different regimes of separated and overlapped levels are observed, resembling the case of random atomic masses investigated previously. At stronger and/or more dense disorder, the particles become essentially inhomogeneous, thus constituting a minimal model ...
Added: August 26, 2021
Koniakhin S., Oleg I. Utesov, Terterov I. et al., Journal of Physical Chemistry C 2018 Vol. 122 No. 33 P. 19219-19229
In crystalline nanoparticles, the Raman peak is downshifted with respect to the bulk material and has asymmetric
broadening. These effects are straightly related to the finite size of nanoparticles, giving the perspective to use Raman spectroscopy as the size probe. By combining the dynamical matrix method (DMM) and the bond polarization model (BPM), we develop a ...
Added: January 16, 2021
Oleg I. Utesov, Yashenkin A., Koniakhin S., Journal of Physical Chemistry C 2018 Vol. 122 No. 39 P. 22738-22749
A simple way to investigate theoretically the Raman spectra (RS) of nonpolar nanoparticles is proposed. For this aim, we substitute the original lattice optical phonon eigenproblem by the continuous Klein−Fock−Gordon-like equation with Dirichlet boundary conditions. This approach provides the basis for the continuous description of optical phonons in the same manner how the elasticity theory ...
Added: January 16, 2021
Y G Vainer, Калмыков А. С., Melentiev P. N. et al., Laser Physics Letters 2020 Vol. 17 No. 10 P. 105901
We offer and demonstrate a new type of plasmonic metasurface for sensorics and
surface-enhanced Raman spectroscopy (SERS) spectroscopy, characterized by a wide spectral
range of sensitivity from 450 nm to 850 nm. The metasurface is formed by Ag nanoparticles of
different sizes. The metasurface has clear anisotropy formed by the Ag nanoparticles’
size-dependent plasmonic resonances. The resonant wavelength of ...
Added: January 17, 2021
Pikovsky A., Journal of Statistical Mechanics: Theory and Experiment 2020 No. 053301 P. 1-12
We study numerical propagation of energy in a one-dimensional Ding-Dong lattice composed of linear oscillators with elastic collisions. Wave propagation is suppressed by breaking translational symmetry, and we consider three ways to do this: position disorder, mass disorder, and a dimer lattice with alternating distances between the units. In all cases the spreading of an ...
Added: October 31, 2020
Pikalov A., Dorofeenko A., Yurii E. Lozovik, Physical Review B: Condensed Matter and Materials Physics 2018 Vol. 98 No. 08-5134 P. 1-14
A method for finding dispersion in chains of plasmonic particles of arbitrary shape is proposed. Our approach is based on analytic continuation via polylogarithms and is basically a generalization of the method known for spherical nanoparticle chains. As an example, we consider an axial chain of split-ring resonators. Three distinct solutions are distinguished, namely, two ...
Added: October 22, 2018
Tarasov B., Arbuzov A., Volodin A. et al., Journal of Alloys and Compounds 2022 Vol. 896 Article 162881
The paper presents a review of the authors’ studies of advanced functional composites of graphene based materials with metals, alloys, intermetallic compounds and their hydrides, and on the creation on their basis of hydrogen-storage materials for a compact and safe hydrogen storage, electrode materials for nickel- metal hydride batteries, highly efficient catalysts for the hydrogenation ...
Added: December 28, 2021
Koniakhin S., Utesov O., Yashenkin A., Physical Review Research 2023 Vol. 5 No. 1 Article 013153
Modification of optical phonon spectra in contacting nonpolar nanoparticles compared to single particles is studied. Optical phonons in dielectric and semiconducting particles obey the Euclidean metric Klein-Fock-Gordon equation with Dirichlet boundary conditions. This equation is supposed to be solved numerically for manifolds of cojoined spheres. It is proposed to replace this problem with the simpler-to-solve ...
Added: March 6, 2023
Кузьмин Н. Н., Климин С. А., Маврин Б. Н. et al., Journal of Physics and Chemistry of Solids 2020 Vol. 138 No. 109266 P. 1-6
We present experimental (by means of the infrared absorption and Raman scattering measurements at room
temperature) and first-principles studies of the lattice dynamics of the recently discovered new compounds
La3CrGe3Be2O14, Pr3CrGe3Be2O14, and Nd3CrGe3Be2O14 belonging to the langasite series and constituting a new
class of low-dimensional antiferromagnets. The observed vibrational modes of all the three compounds are
consistent with the ...
Added: October 22, 2020
O.I. Utesov, Journal of Magnetism and Magnetic Materials 2021 Vol. 524 P. 167616
The analytical theory of density of states (DOS) in three-dimensional quantum magnets with the bond disorder is proposed based on the self-consistent T-matrix
approximation (SCTMA). It successfully describes the DOS both for resonant and non-resonant scattering, whose emergence is governed by the ratio of scattering
length and the average distance between impurities, which concentration is denoted as ...
Added: January 14, 2021
O.I. Utesov, Syromyatnikov A. V., Physical Review B: Condensed Matter and Materials Physics 2019 Vol. 99 No. 13 P. 134412
We theoretically address the problem of cubic B20 helimagnets with a small concentration c <<1 of defect
bonds in external magnetic field H, which is relevant to mixed B20 compounds at small dopant concentrations.
We assume that the Dzyaloshinskii-Moriya interaction and the exchange coupling constant are changed on
imperfect bonds which leads to distortion of the conical spiral ...
Added: January 16, 2021
Томск : Федеральное государственное автономное образовательное учреждение высшего образования "Национальный исследовательский Томский государственный университет", 2010
Представлен ряд схем генераторов наноструктурированных систем, включая аэрозоли, ультрадисперсные порошки (УДП), композитные материалы. В качестве рабочего тела использовались растворы, суспензии, гидрозоли, мелкодисперсные порошки. Для получения наноструктурированных материалов, таких, как аэровзвеси санитарного и метеоэкологического применения в атмосфере, УДП металлов и сплавов композиционных монолитов и покрытий, разработаны струйно-форсуночные, сопловые и плазменные генераторы с включением методов переконденсации исходного ...
Added: March 15, 2019
Loganathan N., Bowers G. M., Ngouana-Wakou B. F. et al., Physical Chemistry Chemical Physics 2019 Vol. 21 P. 6917-6924
The interactions among fluid species such as H2O, CO2, and CH4 confined in nano- and meso-pores in shales and other rocks is of central concern to understanding the chemical behavior and transport properties of these species in the earth’s subsurface and is of special concern to geological C-sequestration and enhanced production of oil and natural ...
Added: November 2, 2019
Golubenko D. V., Shaydullin R., Yaroslavtsev A. B., Colloid and Polymer Science 2019 Vol. 297 No. 5 P. 741-748
In the present paper, the influence of acid–base properties of inorganic particles in ion-exchange membrane-based nanocomposites on their physicochemical and transport properties was investigated. For this purpose, particles of Zr, Ti, and Si oxides have been synthesized in situ in the system of pores and channels of the membranes. Depending on the acid–base properties of ...
Added: November 18, 2019
Ay A. N., Zumreoglu-Karan, B., Kalinichev A. G. et al., Journal of Porous Materials 2020 Vol. 27 P. 735-743
Magnetic nanocomposites involving tetraborate ion (TB)-intercalated Mg–Al-layered double hydroxide (LDH) shell supported on magnesium ferrite core particles are synthesized, characterized, and compared with their non-magnetic analogues. The compositions of the obtained nanocomposites were determined and structural investigations were made by powder X-ray diffraction and Fourier transform infrared spectroscopy. Particle characteristics were examined by size distribution, ...
Added: February 26, 2020
Kozyrev N. V., Akhmadullin R. R., Namozov B. R. et al., Physical Review B: Condensed Matter and Materials Physics 2019 Vol. 99 No. 3 P. 1-7
Multiple Mn2+ spin-flip Raman scattering (SFRS) in Voigt geometry was observed in self-organized disk-shaped quantum dots (QDs) of CdSe/Zn0.99Mn0.01Se, where magnetic ions and QD carriers are spatially separated and therefore the exchange interaction between them is expected to be weak. Many lines (about ten) were observed in SFRS spectra, yet the overlapping of the hole wave function with Mn2+ ions ...
Added: May 31, 2021
Goryainov V., Известия высших учебных заведений. Физика 2010 Т. 53 № 12-2 С. 99-102
Представлен ряд схем генераторов наноструктурированных систем, включая аэрозоли, ультрадисперсные порошки (УДП), композитные материалы. В качестве рабочего тела использовались растворы, суспензии, гидрозоли, мелкодисперсные порошки. Для получения наноструктурированных материалов, таких, как аэровзвеси санитарного и метеоэкологического применения в атмосфере, УДП металлов и сплавов композиционных монолитов и покрытий, разработаны струйно-форсуночные, сопловые и плазменные генераторы с включением методов переконденсации исходного ...
Added: March 15, 2019
Калмыкова Т. П., Костина Ю. В., Ильин С. О. et al., Высокомолекулярные соединения. Серия Б 2020 Т. 62 № 1 С. 68-80
Dispersions based on sodium hyaluronate and hydroxyapatite, which is synthesized both by the classical method in an aqueous medium to obtain submicron particles and in a bioactive hyaluronan medium with the formation of nanosized particles, are obtained. The synthesized hydroxyapatite nanoparticles have a complex structure based on a monodentate complex hyaluronan–Ca2+ which remains in the dispersion ...
Added: January 29, 2023
Kolokolov I., Lebedev V., Chertkov M. et al., JETP Letters 2001 Vol. 74 No. 7 P. 391-395
The propagation of a soliton pattern through one-dimensional medium with weakly disordered dispersion is considered. Solitons, perturbed by this disorder, radiate. The emergence of a long-range interaction between the solitons, mediated by the radiation, is reported. Basic soliton patterns are analyzed. The interaction is triple and is extremely sensitive to the phase mismatch and relative ...
Added: March 4, 2017
Vladimirova Yu.V., Mannanov A. L., Zadkov V.N. et al., Moscow University Physics Bulletin 2018 Vol. 73 No. 6 P. 678-682
The effect of spherical SiO2 nanoparticles of 20 to 80 nm in diameter embedded into the PEDOT: PSS buffer layer of organic solar cells (OSC) based on star-shaped oligomers on their efficiency was studied experimentally in detail. Measurements and analysis of the current-voltage characteristics of the samples, their absorption spectra and study of the morphology ...
Added: February 1, 2019
Самойленко А. А., Левин Г. Г., Lyaskovskii V. et al., Оптика и спектроскопия 2017 Т. 122 № 6 С. 1037-1039
The results of an experimental study of a sensor designed to detect and measure the concentration of nanoparticles in an aqueous medium based on optical dielectric microresonators with "whispering gallery" modes are presented. The change in the frequency and Q of the eigenmodes of the microresonator was studied in its interaction with silver nanoparticles. It ...
Added: October 16, 2017
Яшкардин Р. В., Sorokin K., IEEE NW Russia Young Researchers in Electrical and Electronic Engineering Conference 2016 P. 736-739
a brief description of the principles of functioning of the device for producing an ultradispersive metal powders under the affection of powerful electrically charged energy streams is presented in the article. A method of creating a mathematical model of a device components for producing an ultrsadispersive particles is explained. A comparison of the results of ...
Added: October 15, 2021
Yashenkin A., Utesov O., Koniakhin S., Journal of Raman Spectroscopy 2021 Vol. 52 No. 11 P. 1847-1859
Recent Raman data on nanocrystallite arrays are revised within the microscopic
theory for Raman peaks positions and broadening (linewidth). The theory
combines the elasticity theory-like approach for optical phonons used in
order to evaluate the Raman peaks structure and the Green's function method
applied for the phonon lines broadening. These theories are supported by the
atomistic calculations within the dynamical ...
Added: November 9, 2021