?
Interaction of Nitrite Ions with Hydrated Portlandite Surfaces: Atomistic Computer Simulation Study
Materials. 2023. Vol. 16. No. 14. Article 5026.
The nitrite admixtures in cement and concrete are used as corrosion inhibitors for steel reinforcement and also as anti-freezing agents. The characterization of the protective properties should account for the decrease in the concentration of free NO2− ions in the pores of cement concretes due to their adsorption. Here we applied the classical molecular dynamics computer simulation approach to quantitatively study the molecular scale mechanisms of nitrite adsorption from NaNO2 aqueous solution on a portlandite surface. We used a new parameterization to model the hydrated NO2− ions in combination with the recently upgraded ClayFF force field (ClayFF-MOH) for the structure of portlandite. The new NO2− parameterization makes it possible to reproduce the properties of hydrated NO2− ions in good agreement with experimental data. In addition, the ClayFF-MOH model improves the description of the portlandite structure by explicitly taking into account the bending of Ca-O-H angles in the crystal and on its surface. The simulations showed that despite the formation of a well-structured water layer on the portlandite (001) crystal surface, NO2− ions can be strongly adsorbed. The nitrite adsorption is primarily due to the formation of hydrogen bonds between the structural hydroxyls on the portlandite surface and both the nitrogen and oxygen atoms of the NO2− ions. Due to that, the ions do not form surface adsorption complexes with a single well-defined structure but can assume various local coordinations. However, in all cases, the adsorbed ions did not show significant surface diffusional mobility. Moreover, we demonstrated that the nitrite ions can be adsorbed both near the previously-adsorbed hydrated Na+ ions as surface ion pairs, but also separately from the cations.
Publication based on the results of:
Kryzhanovskaya N., Makhov I., Dragunova A., St. Petersburg Polytechnical University Journal: Physics and Mathematics 2026 Vol. 19 No. 1.1 P. 98–104
The planar microcavity structure was grown using molecular-beam epitaxy.
Single-mode lasing was observed at a wavelength of 960 nm for pillars with a diameter of
15 μm. At 300 K, the lasing threshold was approximately 30 mW. Increasing the pump
power to 2.7 times the threshold power resulted in a mode energy shift of approximately
1 meV. This shift ...
Added: September 23, 2026
Zhukov A., Wang Q., Zeng Y. et al., Nano Letters 2026 Vol. 26 No. 34 P. 11565–11572
Colloidal semiconductor nanorods (NRs) are promising room-temperature single-photon sources because of their
solution processability, tunable optical properties, and intrinsically linearly polarized emission. However, simultaneously achieving high photoluminescence quantum yield (PLQY), strong polarization, and high-purity single-photon emission remains challenging in conventional binary-shell NRs due to the competing requirements of
exciton confinement and core/shell lattice−strain management. Here, we report CdSe/CdZnS gradient alloy core/shell NRs with tunable ...
Added: September 23, 2026
Andreeva S., Gavrilov A. A., Dzhikirba K. R. et al., Physical Review B: Condensed Matter and Materials Physics 2026 Vol. 114 Article 134515
We examine plasma excitations with linear dispersion in a system of superconducting electrons in thin
NbN disks. Using frequency-domain terahertz spectroscopy, we study the evolution of plasmons up to critical
temperature Tc. The observed excitations tend to shift to the lower frequencies while temperature is increasing
and the spectral features vanish at T > Tc. We study the ...
Added: September 23, 2026
Образцова А. А., Ivanov K., Moiseev E. et al., Journal of Physics D: Applied Physics 2026 Vol. 59 No. 30 P. 305103
We demonstrate a thermo-optically tunable microlaser based on an InGaAs/GaAs quantum-dot (QD) active region employing a deformed limaçon-shaped cavity. The asymmetric geometry effectively lifts the degeneracy of high-Q whispering-gallery modes, enabling single-mode lasing. A side-mode suppression ratio exceeds 25 dB over a wide current range. Under continuous-wave electrical pumping, the device achieves a peak output power ...
Added: September 23, 2026
Budkov Y., Journal of Chemical Physics 2026 Vol. 165 No. 12 Article 124105
Exact theories of electrolyte structure must satisfy the nonlocal constraints imposed by electrostatic screening, yet these constraints are most commonly formulated only for homogeneous bulk systems and at the level of two-point correlations. Here, we develop a unified field-theoretic framework that extends them to general inhomogeneous ionic fluids and nonlinear charge correlations. Using a standard ...
Added: September 22, 2026
Боровицкая И. В., Пименов В. Н., Коршунов С. Н. et al., Перспективные материалы 2026 № 10 С. 37–54
Проведено сравнение, обобщение и систематизация механизмов эрозии и разрушения
поверхности малоактивируемых материалов, перспективных для использования в
качестве материалов вакуумной камеры термоядерных реакторов: ванадия, его сплава
V – 10 Ti – 6 Cr – 0,05 Zr – 0,1 Si и вольфрама при последовательном воздействии на
них ионных и тепловых потоков. Тепловые потоки имитировали с помощью мощного
импульсного лазерного излучения (ЛИ), создаваемого ...
Added: September 22, 2026
Iontsev M.A., Mukhin S. I., Fistul M. V., Physical Review B: Condensed Matter and Materials Physics 2016 Vol. 94 No. 17 P. 174–510
We report a theoretical study of the ac response of superconducting quantum metamaterials (SQMs), i.e., an array of qubits (two-level systems) embedded in a low-dissipative resonator. By making use of a particular example of a SQM, namely the array of charge qubits capacitively coupled to the resonator, we obtain a second-order phase transition between an ...
Added: September 22, 2026
Shilov A. L., Elesin L., Kravtsov M. et al., Nature Communications 2026 Vol. 17 No. 1 Article 9734
Identifying the microscopic processes limiting conductivity is essential for understanding correlated quantum materials. In twisted bilayer graphene, metallic resistivity follows ρ ~ Tα with widely varying α, fueling competing interpretations from phonon-limited transport and umklapp scattering to strange metallicity and heavy-fermion renormalization. Here, we use terahertz excitation to selectively heat electrons while keeping the lattice cold, separating ...
Added: September 20, 2026
sobov P., Yakushev I., Shestakov A. et al., Organometallics 2025 Vol. 44 No. 24 P. 2873–2881
Interaction of {Cryptand(K+)}(C60•–) with CpCo(CO)2 yields the air-sensitive crystalline salt {Cryptand(K+)}{CpCo(CO)-η2-C60•–} (1), in which C60•– replaces carbonyl group in CpCo(CO)2. Two Co–C bonds of 2.028(9) and 2.057(8)Å are formed. The magnetic moment of 1 is 1.72 μB, indicating a doublet S = 1/2 spin state of {CpCo(CO)-η2-C60•–} at 300 K. The compound shows a broad ...
Added: September 20, 2026
Копьев А., JETP Letters 2026 Vol. 123 No. 5 P. 310–316
The incompressible three-dimensional Euler equations develop very thin pancake-like regions of exponen tially increasing vorticity. The characteristic thickness of such regions decreases exponentially with time, while the other two dimensions do not change considerably, making the flow near each pancake strongly anisotropic. The pancakes emerge in increasing number with time, which may enhance the anisotropy ...
Added: September 18, 2026
Захаров А. В., Düven H., Capar M. I., Physics Letters A 2026 No. 576 Article 131388
Molecular dynamics simulations were carried out to study the structural properties of nematic pentyl
cyanobiphenyl (5CB) and pentyloxy cyanobiphenyl (5OCB) liquid crystals (LCs) doped with gold nanoparti
cles (GNPs) of different numbers, shapes and sizes. The spherical GNPs of two different radii and rod-like have
been doped in 5CB and 5OCB cyanobiphenyl liquid crystals. In order to describe ...
Added: September 17, 2026
Andreev D. V., Kornev S. A., Bondarenko G.G. et al., Inorganic Materials: Applied Research 2026 Vol. 17 No. 5 P. 1226–1230
Comparative studies are carried out to investigate high-field charge degradation effects in the gate
dielectric of metal—insulator—semiconductor (MIS) structures with aluminum and polysilicon gates.
Charging phenomena in MIS structures are explored using high-field electron injection into the dielectric
under conditions of gradually increasing voltage current density, with periodic short-term switching to a measurement
mode at a constant low injection ...
Added: September 15, 2026
Poddiakov A., / Series Social Science Research Network "Social Science Research Network". 2026. No. 7437658.
Clarity of knowledge and reasoning is necessary in many cases. Yet vagueness in scientific thinking related to surprise, curiosity, "ability to engage with not-knowing" (de Freitas) and abductive reasoning is also a crucially important source of scientific creativity which supplements combinatorial logic when dealing with the already known. Starting from studies by C. S. Peirce ...
Added: September 15, 2026
Water confined in heterogeneous clay–quartz pores: Structure and dynamics from atomistic simulations
Glushak A., Tararushkin E., Smirnov G., Colloids and Surfaces A: Physicochemical and Engineering Aspects 2027 Vol. 752 Article 141756
The molecular-scale behavior of water in heterogeneous clay–quartz systems is critical for understanding cementation processes in natural soils and compacted bentonite, which is crucial for oil recovery and nuclear waste disposal barriers construction. Here we investigate how heterogeneity of mixed Na-montmorillonite and α-quartz surfaces affect water structure and dynamics in nanopores of 2.5 to 60 Å ...
Added: September 15, 2026
Bochkin G., Doronin S., Fel’dman E. et al., Lobachevskii Journal of Mathematics 2024 Vol. 45 No. 3 P. 1188–1207
We consider the remote state restoring and perfect transfer of the zero-order coherence matrix (PTZ) in a spin system governed by the XXZ-Hamiltonian conserving the excitation number. The restoring tool is represented by several nonzero Larmor frequencies in the Hamiltonian. To simplify the analysis we use two approximating models including either step-wise or pulse-type time-dependence ...
Added: September 14, 2026
Nikitiuk B., Nikolay Kondratyuk, Pisarev V., Journal of Molecular Liquids 2025 Vol. 440 Article 128894
Understanding how liquids transition into glassy states under varying thermodynamic conditions remains a fundamental challenge in condensed matter physics. While temperature-driven vitrification has been extensively studied, the effects of high pressure on glass formation are comparatively underexplored -- particularly in molecular liquids. In this work, we employ molecular dynamics simulations to investigate the behaviour of ...
Added: November 12, 2025
Lenev D. Y., Zakharov S. A., V. V. Pisarev, Russian Journal of Physical Chemistry A 2024 Vol. 98 No. 12 P. 2816–2822
Molecular dynamics is used to calculate the vapor–liquid equilibrium and liquid–vapor surface
tension for a methane–ethane system. Good agreement of the parachor value for ethane between the molecular
model and experimental data is shown for the 203–253 K range of temperatures and pressures up to
60 atm. The dependence of the surface tension of the mixture on pressure ...
Added: November 15, 2024
Полянский А. А., Efremov R., Биологические мембраны 2024 Т. 41 № 4 С. 403–421
The paper overviews the results of computational studies of the molecular mechanisms underlying
the adaptation of model cell membranes taking place during their interaction with proteins and peptides. We
discuss changes in the structural and dynamic parameters of the water–lipid environment, the hydrophobic/
hydrophilic organization of the lipid bilayer surface (the so-called “mosaicity”), etc. Taken together,
these effects are ...
Added: September 19, 2024
Pavlova T., Shevlyuga V. M., Journal of Chemical Physics 2024 Vol. 160 No. 5 Article 054701
For the most precise incorporation of single impurities in silicon, which is utilized to create quantum devices, a monolayer of adatoms on the Si(100) surface and a dopant-containing molecule are used. Here we studied the interaction of a phosphorus tribromide with a chlorine monolayer with mono- and bivacancies in a scanning tunneling microscope (STM) at ...
Added: July 2, 2024
T. V. Pavlova, V. M. Shevlyuga, Journal of Chemical Physics 2023 Vol. 159 No. 21 Article 214701
The interaction of the PBr3 molecule with Si dangling bonds (DBs) on a chlorinated Si(100) surface was studied. The DBs were charged in a scanning tunneling microscope (STM) and then exposed to PBr3 directly in the STM chamber. Uncharged DBs rarely react with molecules. On the contrary, almost all positively charged DBs were filled with molecule fragments. ...
Added: January 29, 2024
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
Nikita A. Kosarim, Armeev G., Alexey K. Shaytan et al., Supercomputing Frontiers and Innovations 2022 Vol. 9 No. 2 P. 56–67
The nucleosome is the basic unit of eukaryotic DNA compaction. It consists of about 147 base pairs wrapped around an octamer of histone proteins. Nucleosomal dynamics provides the availability of packaged DNA for various factors that carry out the vital processes associated with chromatin. It is not completely known how the structure and dynamics of ...
Added: September 4, 2023
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
Tararushkin E., Smirnov G., Kalinichev A. G., Minerals 2023 Vol. 13 No. 8 Article 1018
The 10-Å phase is an important member of the family of dense hydrous magnesium silicates (DHMSs) that play a major role in the water budget in the Earth’s upper mantle. Its nominal composition is usually written as Mg3Si4O10(OH)2·xH2O, and its structure is often described as layers of talc with some amount of water present in ...
Added: August 1, 2023