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NMR diffusion studies of proton-exchange membranes in wide temperature range
Journal of Membrane Science. 2020. Vol. 596. Article 117691.
Galitskaya E., Privalov A., Weigler M., Vogel M., Vitaly Sinitsyn
It is established that the values of the coefficients of self-diffusion of water in proton-exchange membranes at a fixed temperature and the amount of moisture content depend on the method of membrane manufacture, the length of the side chain (diameter of channels), but within the experimental error do not depend on the thickness of the membrane. It is shown that at low hydration, a "short-chain" membrane is more preferable for practical use in a fuel cell than a membrane with a long side chain.
Privalov A., Vitaly V. Sinitsyn, Vogel M., The Journal of Physical Chemistry Letters 2023 Vol. 14 No. 30 P. 9335-9340
We use 1H and 17O NMR static field gradient diffusometry to measure self-diffusion coefficients of protons (DH) and oxygens (DO) in Nafion 212 with various hydration levels (λ = 4–18). For all samples and both nuclei, we obtain activation energies (Ea) of ≈0.19 eV. Analyzing the hydration-level dependence of DH and DO, we find DO/DH ≈ 1 at λ ≈ 18, resembling ...
Added: October 13, 2023
Vladimir A. Korshun, Prokhorenko I., Tyurin A. et al., MedChemComm 2018 Vol. 9 No. 4 P. 667-675
The study of an archived sample of crystallomycin complex using HPLC, ESI HRMS, and 2D NMR showed
that two major components of the antibiotic, compounds 1 and 2, are lipopeptides having the same peptide
core, Asp1-cycloIJDab2-Pip3-MeAsp4-Asp5-Gly6-Asp7-Gly8-Dab9-Val10-Pro11-), N-acylated either
with Δ3-iso-tetradecenoyl or Δ3-anteiso-pentadecenoyl that are identical to aspartocins C and B, respectively.
According to the 2D NMR study, compound 2 ...
Added: November 8, 2019
Darya Gurina, Ekaterina Odintsova, Krestyaninov M. A. et al., Journal of Molecular Liquids 2023 Vol. 390 No. A Article 122961
The paper presents a study of the behavior of room-temperature ionic liquids with different alkyl chain lengths and anion types in slit negatively charged carbon nanopores of various widths (1÷15 nm) using all-atom molecular dynamics simulations. The structure of the confined ionic liquids is investigated using number, mass, and charge density profiles and radial distribution ...
Added: August 31, 2023
Novikov S.V., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 2018 Vol. 98 No. 1 P. 012128-1- 012128-8
We demonstrate that the Einstein relation for the diffusion of a particle in the random-energy landscape with the
Gaussian density of states is an exclusive one-dimensional property and does not hold in higher dimensions. We
also consider the analytical properties of the particle velocity and diffusivity for the limit of weak driving force and
establish a connection between ...
Added: July 23, 2018
Antropov A., Stegailov V., Journal of Nuclear Materials 2023 Vol. 573 Article 154123
The influence of helium pressure on the mechanisms of diffusion of the He-filled nanobubbles in fcc Al is investigated by the classical molecular dynamics. It is shown that at pressures <20 kbar gas suppresses self-diffusion, while the concentration of adatoms, rather than their mobility, plays a key role. However, as the pressure increases to values at which ...
Added: February 1, 2023
Panina I., Balandin S., Tsarev A. et al., International Journal of Molecular Sciences 2023 Vol. 24 No. 2 P. 1
To date, a number of lantibiotics have been shown to use lipid II — a highly conserved peptidoglycan precursor in the cytoplasmic membrane of bacteria — as their molecular target. The α-component (Lchα) of the two-component lantibiotic lichenicidin (Lchα), previously isolated from the Bacillus licheniformis VK21 strain, seems to contain two putative lipid II binding ...
Added: February 21, 2023
Yu K. B., Bowers G. M., Loganathan N. et al., Energy & Fuels 2021 Vol. 35 No. 20 P. 16515-16526
As global energy demand increases, natural gas recovery from source rocks is attracting considerable attention since recent development in shale extraction techniques has made the recovery process economically viable. Kerogens are thought to play an important role in gas recovery; however, the interactions between trapped shale gas and kerogens remain poorly understood due to the ...
Added: November 3, 2021
Ivchenko N., Vergeles S. S., Журнал экспериментальной и теоретической физики 2023 Т. 163 № 5 С. 724-733
We study statistical properties of the passive scalar advection in a 2D flow that consist of a steady-state shear flow and a relatively weak smooth random component taking into account the effects of finite weak diffusion. The model is closely related to the dynamics of passive scalar transfer inside coherent vortices emerging as a result ...
Added: February 15, 2024
Galitskaya E., Privalov A., Vogel M. et al., Journal of Chemical Physics 2021 Vol. 154 No. 3 Article 034904
The Field Cycling (FC) 2H NMR relaxometry was applied to study dynamics in Nafion NR 212 in the temperature range from 300K to 190K and water content l=8.2. The sensitive time window of FC was extended up to 8 decades using temperature-frequency superposition principle and master curve. The rotational correlation times obtained from 2H FC ...
Added: September 16, 2022
Glazov M., Physical Review Letters 2020 Vol. 124 P. 166802
We study theoretically weak localization of excitons in atomically thin transition metal dichalcogenides. The constructive interference of excitonic de Broglie waves on the trajectories forming closed loops results in a decrease of the exciton diffusion coefficient. We calculate the interference contribution to the diffusion coefficient for the experimentally relevant situation of exciton scattering by acoustic ...
Added: January 13, 2021
Дещеня В. И., Kondratyuk N., Ланкин А. В. et al., Журнал физической химии 2022 Т. 96 № 3 С. 373-380
The temperature dependence of density is calculated for an aqueous solution of sucrose by the molecular dynamics method. The coefficients of viscosity and diffusion are also obtained in the 273–343 K range of temperatures. The hydrodynamic radius of a sucrose molecule in an aqueous solution is calculated. The obtained data are compared with the experimental ...
Added: October 24, 2022
Deshchenya V. I., N. D. Kondratyuk, Lankin A. V. et al., Journal of Molecular Liquids 2022 Vol. 367 Article 120456
In this work, we study the applicability of the equilibrium molecular dynamics methods for the prediction of both static and dynamic properties of sucrose aqueous solution for various concentrations and temperatures.
The OPLS-AA force field with 1.14*CM1A charge corrections is used to describe the interactions in the model.
We analyze the prediction power of the model against ...
Added: August 9, 2022
Glazov M., Physical Review B: Condensed Matter and Materials Physics 2019 Vol. 100 P. 034703-1-034703-13
We study theoretically the nonequilibrium exciton transport in monolayer transition metal dichalcogenides. We consider the situation where excitons interact with nonequilibrium phonons, e.g., under the conditions of localized excitation where a “hot spot” is formed. We develop the theory of the exciton drag by the phonons and analyze in detail the regimes of diffusive propagation ...
Added: January 13, 2021
Nikita S. Komarov, Vladimir M. Shevlyuga, Loginov B. et al., Journal of Physical Chemistry C 2023 Vol. 127 No. 5 P. 2266-2273
Adsorption of molecular chlorine onto the Ag(110) surface has been studied with low-temperature scanning tunneling microscopy, low-energy electron diffraction, and density functional theory calculations (DFT). At a coverage of 1/2 ML, chlorine forms a p(2 × 1) structure, which, with a further increase in coverage, transforms into a p(3 × 1) structure consisting of dimer rows. DFT ...
Added: June 27, 2023
Zavorotnaya U., Igor I. Ponomarev, Volkova Y. et al., Materials 2020 Vol. 22 No. 13 Article 5297
The sulfonated polynaphthoyleneimide polymer (co-PNIS70/30) was prepared by copolymerization of 4,4′-diaminodiphenyl ether-2,2′-disulfonic acid (ODAS) and 4,4’-methylenebisanthranilic acid (MDAC) with ODAS/MDAC molar ratio 0.7/0.3. High molecular weight co-PNIS70/30 polymers were synthesized either in phenol or in DMSO by catalytic polyheterocyclization in the presence of benzoic acid and triethylamine. The titration reveals the ion-exchange capacity of the polymer ...
Added: October 20, 2022
Gavryushkin P., Belonoshko Anatoly B., Sagatov N. et al., Crystal Growth & Design 2021 Vol. 21 No. 1 P. 65-74
Using molecular dynamics simulation and evolutionary metadynamic calculations, a series of structures were revealed that possessed enthalpies and Gibbs energies lower than those of aragonite but higher than those of calcite. The structures are polytypes of calcite, differing in the stacking sequence of close-packed (cp) Ca layers. The two- and six-layered polytypes have hexagonal symmetry P6322 ...
Added: January 21, 2021
Голосов Е. В., Алдошин С. М., Палий А. В. et al., Reviews and Advances in Chemistry 2021 Vol. 11 No. 3-4 P. 145-165
This article is a short overview of the problem of controllable magnetic spin communicationas an important ingredient of spintronics and molecular electronics. We discuss the problem of communicationof the two localized spins mediated by the mobile electron which is shared between twonon-magnetic sites coupled to the mobile spins. The model system which is assumed to ...
Added: October 10, 2022
Kolesnikov A. L., Budkov Y., Barbosa G. D. et al., Fluid Phase Equilibria 2023 No. 564 Article 113567
Theoretical modeling of water adsorption in micro- and mesoporous materials remains a challenging problem for physical chemistry and chemical engineering despite its great importance for industrial applications. Here, we present the theoretical study of bulk and inhomogeneous water within the classical density functional theory. Our model includes all important intermolecular interactions, such as dispersion, association, ...
Added: August 30, 2022
Konarev D., Salavat S. Khasano, Mikhailenko M. et al., European Journal of Inorganic Chemistry 2021 Vol. 2021 No. 1 P. 86-92
New methods to prepare anionic HATNA coordination complexes from iron metal or iron carbonyls yielded (CV+)2{HATNA(FeIICl2)3}2− ⋅ 3.5C6H4Cl2, where CV+ is the crystal violet cation. The FeII atoms have a high S=2 spin state and form equilateral triangles. The exchange interaction constant between high-spin FeII is J=−4.6 cm−1 indicating antiferromagnetic coupling of spins as well as a rather ...
Added: October 22, 2022
Budkov Y., Kalikin N., Physical Review E - Statistical, Nonlinear, and Soft Matter Physics 2023 Vol. 107 No. 2 Article 024503
In this paper, we present a self-consistent field theory of macroscopic forces in spatially inhomogeneous flexible chain polyelectrolyte solutions. We derive an analytical expression for a stress tensor which consists of three terms: isotropic hydrostatic stress, electrostatic (Maxwell) stress, and stress rising from conformational entropy of polymer chains—conformational stress. We apply our theory to the ...
Added: February 15, 2023
Kalikin N., Budkov Y., Kolesnikov A. L. et al., Fluid Phase Equilibria 2021 Vol. 544-545 Article 113096
Despite the modern level of development of computational chemistry methods and technological progress, fast and accurate determination of solvation free energy remains a huge problem for physical chemists. In this paper, we describe two computational schemes that can potentially solve this problem. We consider systems of poorly soluble drug compounds in supercritical carbon dioxide. Considering that the biggest contribution ...
Added: June 1, 2021
Pavlova T., Eltsov K., Андрюшечкин Б. В. et al., Journal of Physical Chemistry C 2018 Vol. 122 No. 50 P. 28862-28867
Coadsorption of chlorine and oxygen on the Ag(111) surface has been studied with low-temperature scanning tunneling microscopy in combination with density functional theory calculations. Room-temperature adsorption of chlorine onto the Ag(111)-p(4 X 4)-O surface leads to the appearance of new bright objects located between protrusions of the 4 X 4 reconstruction. As chlorine adsorbs, objects form "rosettes" around corner holes. This configuration coincides with the configuration of the chlorine atoms in the Ag(111)-(3 X 3) Cl reconstruction structure. We conclude that the adsorption of chlorine on the Ag(111)-p(4 x 4)-O surface ...
Added: October 25, 2021
Maslov V., Теоретическая и математическая физика 2019 Т. 201 № 1 С. 65-83
We study the process of a nucleon separating from an atomic nucleus from the mathematical standpoint
using experimental values of the binding energy for the nucleus of the given substance. A nucleon becomes
a boson at the instant of separating from a fermionic nucleus. We study the further transformations of
boson and fermion states of separation in a ...
Added: November 1, 2019
Budkov Y., Journal of Physics: Condensed Matter 2019 Vol. 31 P. 078002-078003
We reply to the comment on our paper by Budkov (2018 J. Phys.: Condens. Matter 30 344001). ...
Added: January 4, 2019