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Öğe Ab Initio Insight into the Interaction of Metal-Decorated Fluorinated Carbon Fullerenes with Anti-COVID Drugs(Mdpi, 2022) Katin, Konstantin P.; Kochaev, Alexey I.; Kaya, Savas; El-Hajjaji, Fadoua; Maslov, Mikhail M.We theoretically investigated the adsorption of two common anti-COVID drugs, favipiravir and chloroquine, on fluorinated C-60 fullerene, decorated with metal ions Cr3+, Fe2+, Fe3+, Ni2+. We focused on the effect of fluoridation on the interaction of fullerene with metal ions and drugs in an aqueous solution. We considered three model systems, C-60, C60F2 and C60F48, and represented pristine, low-fluorinated and high-fluorinated fullerenes, respectively. Adsorption energies, deformation of fullerene and drug molecules, frontier molecular orbitals and vibrational spectra were investigated in detail. We found that different drugs and different ions interacted differently with fluorinated fullerenes. Cr3+ and Fe2+ ions lead to the defluorination of low-fluorinated fullerenes. Favipiravir also leads to their defluorination with the formation of HF molecules. Therefore, fluorinated fullerenes are not suitable for the delivery of favipiravir and similar drugs molecules. In contrast, we found that fluorine enhances the adsorption of Ni2+ and Fe3+ ions on fullerene and their activity to chloroquine. Ni2+-decorated fluorinated fullerenes were found to be stable and suitable carriers for the loading of chloroquine. Clear shifts of infrared, ultraviolet and visible spectra can provide control over the loading of chloroquine on Ni2+-doped fluorinated fullerenes.Öğe Ab initio Study of Hydrogen Adsorption on Metal-Decorated Borophene-Graphene Bilayer(Mdpi, 2021) Grishakov, Konstantin S.; Katin, Konstantin P.; Kochaev, Alexey I.; Kaya, Savas; Gimaldinova, Margarita A.; Maslov, Mikhail M.We studied the hydrogen adsorption on the surface of a covalently bonded bilayer borophene-graphene heterostructure decorated with Pt, Ni, Ag, and Cu atoms. Due to its structure, the borophene-graphene bilayer combines borophene activity with the mechanical stability of graphene. Based on the density functional theory calculations, we determined the energies and preferred adsorption sites of these metal atoms on the heterostructure's borophene surface. Since boron atoms in different positions can have different reactivities with respect to metal atoms, we considered seven possible adsorption positions. According to our calculations, all three metals adsorb in the top position above the boron atom and demonstrate catalytic activity. Among the metals considered, copper had the best characteristics. Copper-decorated heterostructure possesses a feasible near-zero overpotential for hydrogen evolution reaction. However, the borophene-graphene bilayer decorated with copper is unstable with respect to compression. Small deformations lead to irreversible structural changes in the system. Thus, compression cannot be used as an effective mechanism for additional potential reduction.Öğe All-Nitrogen Cages and Molecular Crystals: Topological Rules, Stability, and Pyrolysis Paths(Mdpi, 2020) Katin, Konstantin P.; Merinov, Valeriy B.; Kochaev, Alexey I.; Kaya, Savas; Maslov, Mikhail M.We combined ab initio molecular dynamics with the intrinsic reaction coordinate in order to investigate the mechanisms of stability and pyrolysis of N-4 divided by N-120 fullerene-like nitrogen cages. The stability of the cages was evaluated in terms of the activation barriers and the activation Gibbs energies of their thermal-induced breaking. We found that binding energies, bond lengths, and quantum-mechanical descriptors failed to predict the stability of the cages. However, we derived a simple topological rule that adjacent hexagons on the cage surface resulted in its instability. For this reason, the number of stable nitrogen cages is significantly restricted in comparison with their carbon counterparts. As a rule, smaller clusters are more stable, whereas the earlier proposed large cages collapse at room temperature. The most stable all-nitrogen cages are the N-4 and N-6 clusters, which can form the van der Waals crystals with densities of 1.23 and 1.36 g/cm(3), respectively. The examination of their band structures and densities of electronic states shows that they are both insulators. Their power and sensitivity are not inferior to the modern advanced high-energy nanosystems.Öğe Anisotropic Carrier Mobility and Spectral Fingerprints of Two- Dimensional ?-Phosphorus Carbide with Antisite Defects(Amer Chemical Soc, 2023) Katin, Konstantin P.; Maslov, Mikhail M.; Nikitenko, Vladimir R.; Kochaev, Alexey I.; Kaya, Savas; Prezhdo, Oleg, VWe apply density functional theory to study carrier mobility in a gamma-phosphorus carbide monolayer. Although previous calculations predicted high and anisotropic mobility in this material, we show that the mobility can be significantly influenced by common antisite defects. We demonstrate that at equilibrium concentrations defects do not inhibit carrier mobility up to temperatures of 1000 K. However, defects can change the mobility at high nonequilibrium concentrations of about 10-4 to 10-2 defects per atom. At the low end of this concentration range, defects act as traps for charge carriers and inhibit their mobility. At the high end of this range, defects change the effective carrier masses and deformation potentials, and they can lead to both an increase and a decrease in mobility. We also report the Raman and IR spectra associated with antisite defects. We predict new vibrational modes and shifts of the existing modes due to the defects.Öğe Applied and computational investigation of plasticizing effects of dibutyl maleate on polymethyl methacrylate acrylic resin material(Elsevier, 2024) Tugut, Faik; Bolayir, Giray; Gulnahar, Evrem; Kaya, Savas; Boztug, Ali; Maslov, Mikhail M.In this study, the amount of change in the glass transition temperature (Tg) of PMMA was analyzed by DSC by adding different ratios of dibutyl maleate (DBM) plasticizer to polymethyl methacrylate (PMMA), which is used as the main ingredient of prosthetics in dentistry. For this, liquid DBM was added to powdered PMMA at a rate of 2, 5, 8 and 15 % by mass, and polymerization was carried out at 100 degrees C. Mechanical tests such as impact resistance, transverse resistance and maximum flexion tests were applied to these prepared mixtures. It was observed that there was a significant parallelism between the Tg values calculated from the DSC curves and the mechanical tests. The Tg value of PMMA was reduced by approximately half with the addition of DBM plasticizer. Additionally, the chemical interaction between PMMA and DBM was analyzed in the light of the Density Functional Theory (DFT) calculations. The binding energy for the mentioned interaction was determined as 1.591 eV. After both species interacted with each other, the glass transition temperature of the formed complex system was theoretically also predicted through the quantitative structure-property relationship (QSPR) model. For theoretical prediction of Tg, the molecular traceless quadrupole moment Theta and the molecular average hexadecapole moment phi, are used. The change determined as experimental in glass transition temperature as a result of the interaction between PMMA and DBM was supported with theoretical calculations. Experimental and theoretical data are in good agreement.Öğe Combination of doped amorphous carbon based dispersive solid phase extraction with ionic liquid-based DLLME for the extraction of aromatic amines from leather industries wastewater; Theoretical and experimental insights(Elsevier, 2023) Nemati, Mahboob; Farajzadeh, Mir Ali; Altunay, Nail; Tuzen, Mustafa; Kaya, Sava; Maslov, Mikhail M.; Mogaddam, Mohammad Reza AfsharIn the present investigation, combination of dispersive solid phase extraction with ionic liquid-based dis-persive liquid-liquid microextraction was used for the extraction of several aromatic amines from leather industries wastewater. In this approach, initially, N and S doped carbon was used for the adsorption of the analytes from the sample solution and then they were concentrated by the subsequent microex-traction step. Determination of the extracted analytes was performed using high performance liquid chromatography-ultraviolet detector. The sorbent contact area with the sample solution was enhanced by performing aspiration/dispersion cycles. In the microextraction procedure, the analytes were enriched into a few microliters of an ionic liquid. Also, interactions between some ionic liquids and the studied aromatic amines were analyzed in the light of performed density-functional theory calculations. The cal-culated quantum chemical parameters and binding energies for the interactions between ionic liquids of the selected amines showed that the analytes interact powerful with the mentioned ionic liquids and it favorite for the method. The optimized method validation was followed by evaluating several figures of merit and the obtained data showed that limits of detection and quantification, precision (expressed as relative standard deviation), enrichment factor, and extraction recovery were in the ranges of 0.25- 0.71 and 0.86-2.4 ng/mL, 3.9-5.2%, 252-312, and 63-78%, respectively. The introduced approach was used in determination of the analytes in the wastewater samples collected from leather manufacturers and p-anisidine, p-chloroaniline, and diethylaniline were determined in them, successfully.(c) 2023 Elsevier B.V. All rights reserved.Öğe Construction of novel BiOI/CuInS2/ZnO dual S-scheme charge transfer pathway for efficient antibiotic degradation(Pergamon-Elsevier Science Ltd, 2024) Banyal, Rahul; Sudhaik, Anita; Kumar, Rohit; Raizada, Pankaj; Ahamad, Tansir; Kaya, Savas; Maslov, Mikhail M.The present work explored the photocatalytic activity of BiOI-CuInS2-ZnO ternary heterojunction for the photodegradation of the tetracycline (TCl). The bare photocatalysts were prepared via hydrothermal method while the ternary heterojunction was synthesized using simple physical mixing route. The ternary heterojunction of BiOI, CuInS2 and ZnO followed the S-scheme charge transfer pathway exhibiting superior photodegradation ability compared to other synthesized photocatalysts. The attained degradation efficiency of BiOI-CuInS2-ZnO Sscheme ternary heterojunction was 96.75 % within 90 min of light illumination which was much higher than other photocatalysts. Electron spin resonance (ESR) investigations and scavenging experiment indicated that O-center dot(2)-, and (OH)-O-center dot radicals plays an important role in photodegradation of TCl. Furthermore, the structural analysis of synthesized bare photocatalysts was also done via density functional theory (DFT) calculations. The results showed that after the formation of S-scheme heterojunction, the ternary heterojunction showed lower recombination rate (validated via PL analysis) with boosted charge carriers separation rate (confirmed through EIS and TPR analysis) and light absorption ability. This had led to upgradation in photodegradation efficiency of ternary BiOI-CuInS2-ZnO photocatalyst. The reusability test of the photocatalysts confirmed excellent stability of ternary photocatalysts with 90.25 % degradation rate up to five catalytic cycles.Öğe Covalently Bonded 1D Chains and 2D Networks From Si-Doped CL-20: Computational Study(Springer/Plenum Publishers, 2025) Gimaldinova, Margarita A.; Maslov, Mikhail M.; Kaya, Savas; Katin, Konstantin P.To discover high-energy-density materials with characteristics superior to current models, it is necessary to study a wide range of potential structures. A promising representative of new derivatives of the class of high-energy compounds is silicon-substituted molecules CL-20, which have a reactivity and kinetic stability close to pure CL-20 but have a higher density and energy release. Low-dimensional covalent SiCL-20 nanostructures based on silicon analogue of the classical CL-20 high-energy molecule are considered in this work. Covalent nanostructures may have advantages over molecular crystals due to their special properties, such as higher packing density and kinetic stability. It has been established that silicon-substituted CL-20 molecules can connect through CH2 molecular bridges into covalent structures. Geometrical parameters, energy characteristics, electronic properties, and quantum chemical reactivity descriptors for several representatives of 1D and 2D systems based on Si5CL-20 have been calculated using density functional theory. The skeleton of each silicon fragment of the CL-20 system undergoes small changes when combined into covalent chains and networks. Still, the systems retain their consistency, and the effective diameter of the silicon frameworks in the nanostructure takes average values from 4.300 to 4.462 & Aring;. The binding energy of nanostructures increases with the number of silicon CL-20 fragments in the system. The binding energies for a single silicon molecule CL-20 and a double chain SiCL-20 consisting of 12 fragments are 3.846 and 4.077 eV/atom, respectively. Thus, the silicon nanostructures become more thermodynamically stable with increasing the size and dimension of the compound. The study of electronic characteristics made it possible to establish that the value of the HOMO-LUMO gap decreases with an increasing number of fragments in the system, and the considered SiCL-20 covalent molecules can be classified as wide-gap semiconductors, like their classical CL-20 analogues. For example, the values of the HOMO-LUMO gaps for silicon derivatives of CL-20 with dimensions 1 x 1, 6 x 1, 6 x 2, and 4 x 3L are 5.601, 4.378, 4.004, and 3.882 eV respectively. Despite their highly stressed skeleton, they are stable enough to be considered for energy applications and are promising candidates for building blocks of high-energy materials and fuels.Öğe Crystal chemistry, DFT calculation and optical properties of the double perovskite stannate Sr2Sn0.8In0.8W0.4O6(Elsevier, 2022) Belgacem, Besma; Maslov, Mikhail M.; Kaya, Savas; Ali, Ismat H.; Ben Hassen, RachedSr2Sn0.8In0.8W0.4O6 double perovskite powder was, first, prepared following an experimental study on the effects of substitutions of In and W in the high transparent strontium stannate SrSnO3 (SSO). The high temperature solid state reaction method was adopted for the preparation of the desired phase. Further, the W and In substitution's effects on the variation of the electronic structure was investigated theoretically by density functional theory (DFT) calculations. Rietveld's refinement of the X-ray diffraction pattern announces a tetragonal symmetry of the crystal lattice (I4/m), characterized by a reduction in octahedral inclinations due to double substitution. IR absorption spectroscopy announced the presence of carbonates and water molecules due to moisture-swing sorption and confirmed by TG analysis. The optical properties studied by UV-Vis spectroscopy have shown that the material is transparent in the visible region of the spectrum. A band gap of 3.46 eV was calculated using Tauc plot, indicating a possible semiconducting behavior. (C) 2022 Elsevier B.V. All rights reserved.Öğe Density Functional Theory Computations and Experimental Analyses to Highlight the Degradation of Reactive Black 5 Dye(Wiley-V C H Verlag Gmbh, 2023) Yildiz, Sayiter; Canbaz, Gamze Topal; Kaya, Savas; Maslov, Mikhail M.The oxidative degradation of Reactive Black 5 (RB5) in aqueous solution was investigated using Fenton (FP), photo Fenton (P-FP), sono Fenton (S-FP), and sono photo Fenton (S-P-FP) processes. Degradation experiments showed efficient dye degradation for FP, P-FP, S-FP, and S-P-FP under optimal conditions. The half-life values of the reaction calculated for first-order reaction kinetics showed that the S-FP process is faster than the FP and P-FP processes. Using DFT calculations, the chemical reactivities of the studied chemical systems were analyzed. Especially the calculated chemical hardness values reflect the reactivities of the dye and the dye-Fe2+ complex. The calculated binding energy between the Fe2+ ion and RB5 of 15.836 eV is compatible with the prediction made in the light of the principle of hard and soft acids and bases. The computed data supported the experimental observations.Öğe Electronic and optical characteristics of graphene on the molybdenum ditelluride substrate under the uniform mechanical stress(Elsevier Science Sa, 2023) Kulyamin, Pavel A.; Kochaev, Aleksey I.; Maslov, Mikhail M.; Flores -Moreno, Roberto; Kaya, Savas; Katin, Konstantin P.The study presents the effect of opening a semiconductor gap in graphene on the molybdenum ditelluride substrate under mechanical stresses using the density functional theory. It has been shown that uniform compression cannot only open the gap due to graphene sheet deformation but also adjust the gap size depending on the compression strength. The maximum gap found was 0.8 eV when the structure was compressed by 8 %, which is confirmed by further analysis of the UV-vis spectrum. Uniform stretching in contrast does not lead to a significant gap opening. The binding energy of the graphene sheet with the molybdenum ditelluride substrate does not change significantly when mechanical stresses are applied. An additional analysis of the Raman and IR spectra will make it possible to determine the degree of compression of graphene on a molybdenum ditelluride substrate in the experiment. In this case, the corresponding modes mainly correspond to vibrations of carbon atoms in the graphene plane or perpendicular to the substrate. The substrate itself does not make a significant contribution to these vibrational modes.Öğe Elucidating the mechanisms of AV17 and BB41 dye degradation through combined computational and applied analyses(Elsevier, 2024) Yildiz, Sayiter; Kaya, Savas; Canbaz, Gamze Topal; Maslov, Mikhail M.This study delved into the degradation efficiencies of Basic Blue 41 (BB41) and Acid Violet 17 (AV17) azo dyes employing various Fenton reactions, including Fenton (FP), photo-Fenton (P-FP), sono-Fenton (S-FP), and sonophoto-Fenton (S-P-FP) processes. The primary goal was to pinpoint the optimal degradation conditions by meticulously examining variables such as H2O2 and Fe2+ concentrations, reaction time, pH, and dye concentration. Density Functional Theory (DFT) calculations revealed the interaction between Fenton reagents and dye molecules, and crucial quantum chemical parameters reflecting the dye's reactivity were computed. The degradation efficiencies for AV17 in FP, P-FP, S-FP, and S-P-FP processes stood at 85 %, 92.6 %, 93.8 %, and 86.9 %, respectively. Meanwhile, for BB41, the corresponding efficiencies were 97.2 %, 98.1 %, 97.8 %, and 97.5 %. Notably, DFT-calculated data corroborated experimental observations, shedding light on the degradation mechanism. This study significantly advances existing research by demonstrating the efficacy and reliability of Fenton-like processes in degrading AV17 and BB41 dyes. The findings underscore the potential of these processes in addressing environmental concerns associated with azo dyes.Öğe Illumination of biosorption of Allura Red on Rhus coriaria L. (sumac) plant: equilibrium, kinetic, thermodynamic, and density functional theory-based analyses(Springer Heidelberg, 2024) Caylak, Osman; Cetintas, Halil Ibrahim; Celik, Muhammed Safa; Kaya, Nurevsan; Cetinkaya, Serap; Maslov, Mikhail M.; Kaya, SavasIn the present paper, the biosorption capability of Rhus coriaria L. (sumac) plant for the effective removal of Allura Red (AR) dye from wastewater was tested in the light of theoretical and experimental tools. The reactive functional groups in the structure of the studied biosorbent and the surface morphology of the mentioned biosorbent were highlighted with the help of FTIR spectrophotometer, SEM (scanning electron microscopy), and EDX (energy-dispersive X-ray analysis). The effect of important parameters such as pH, time, adsorbent mass, and temperature on the biosorption process was checked and discussed in detail. pH 2 was determined as the optimum value for the highest biosorption. Maximum effectiveness was reached at a biosorbent mass of 200 mg. The biosorption process adhered to the Langmuir isotherm and PSO kinetic models, and the process was determined to have a spontaneous and exothermic nature. Through the recovery experiments, it was noted that the studied plant retained approximately 30% of its biosorption capacity after three cycles. To prove the power of the interaction between Allura Red dye and dominant components of Rhus coriaria L. (sumac), density functional theory calculations were performed. Theoretically obtained conceptual DFT-based descriptors, the comments made within the framework of popular electronic structure rules, and calculated adsorption energies were in good agreement with the experimentally obtained data. As a result, it was reported that Rhus coriaria L. can be used as an effective and useful biosorbent for the removal of AR from wastewater.Öğe Interaction of dopants and functional groups adsorbed on the carbon fullerenes: Computational study(Elsevier, 2020) Salem, Mahmoud A.; Katin, Konstantin P.; Kaya, Savas; Kochaev, Alexei I.; Maslov, Mikhail M.We apply density functional theory to study the effective interaction between dopant atoms (B, N, Si, P) and functional groups (H, F, Cl, OH) on the surface of carbon fullerenes. Both dopant atoms and functional groups strongly interact through the carbon cage even in diametrically opposite positions. Interaction energies distribute in a wide range from 0.1 to 2 eV and non-monotonically depend on fullerene size and distance between dopants or functional groups. Such interaction cannot be described as a simple Coulomb repulsion or sum of dopants binding energies and cage strain energy. We identify some general trends in relative positions of dopants or functional groups in low-energy isomers. Para position of two functional groups is the most feasible for C-60 and larger cages. For lower fullerenes, ortho or other spaced positions may be more preferable. The interaction of foreign atoms embedded into the carbon cages is more complicated. The best relative positions intricately depend on the cage size and chemical nature of dopants. As a rule, ortho and para locations are feasible for C-60 and larger cages. However, some exceptions are observed. The effect of thermal vibrations on the considered interactions in doped or functionalized fullerenes is negligible in the temperature range from 300 to 1000 K.Öğe Interaction of pristine and novel graphene allotropes with copper nanoparticles: Coupled density functional and molecular dynamics study(Elsevier Science Sa, 2023) Katin, Konstantin P.; Kochaev, Alexey I.; Bereznitskiy, Igor V.; Kalika, Elizaveta B.; Kaya, Savas; Flores-Moreno, Roberto; Maslov, Mikhail M.We combined the density functional theory and classical molecular dynamics to study the time evolution and thermal stability of copper nanoparticles wrapped in graphene flakes. We observed a strong attraction between nanoparticles and flakes, which was underestimated in many previous simulations. We found that the twoparameter Lennard-Jones potential with parameters & epsilon; = 0.074 eV and r0 = 3.310 & ANGS; reproduces DFT data better than other empirical potentials. We confirmed that a nanoparticle could be held reliable inside a graphene flake. The graphene-coated copper system remains stable over the temperature range of 300-1000 K. In addition to pristine graphene, we considered several strained allotropes containing pentagons, as well as heptagons, octagons, and nanometer-sized pores. Strained allotropes interact with copper nanoparticles approximately twice more strongly as compared to pristine graphene. Molecular dynamics revealed nanoparticle flattening due to strong interaction with graphene allotropes at elevated temperatures. The wettability of graphene with respect to copper strongly depends on the sheet structure and can vary significantly for different allotropes. The results may be useful for further research on copper-graphene composites, which are suitable for catalytic and biomedical applications.Öğe Investigating the optical, electronic, magnetic properties and DFT of NiO films prepared using RF sputtering with various argon pressures(ELSEVIER, 2023) Hopoğlu, Hicret; Kaya, Doğan; Maslov, Mikhail M.; Kaya Savaş; Demir İlkay; Altuntaş İsmail; Ungan, Fatih; Akyol, Mustafa; Ekicibil, Ahmet; ŞenadımTüzemen, EbruIn this study, we investigated the structural, optical, magnetic, and conductive properties of nickel oxide (NiO) films on glass substrates deposited using Radio Frequency (RF) magnetron sputtering with varying Ar gas pressure and thickness. X-ray diffraction and Rietveld refinement analysis confirmed a cubic crystal structure and showed that the lattice parameters and the d(111)-space increased from 4.0559 Å to 4.2712 Å and from 2.3208 Å to 2.4582 Å, respectively, due to increased Ar pressure during deposition. Scanning electron microscopy and atomic force microscopy were used to determine the cross-sectional and surface topology of the NiO films, which exhibited uniform and homogeneous growth with an average spherical size of 54.28 ± 0.33 nm. The optical bandgap values of the films were calculated to be between 3.26 and 3.65 eV, increasing with pressure. Hall measurements confirmed the p-type semiconductor nature of the films with an average sheet carrier density of 1010 cm 2. The films exhibited soft magnetic properties, with a maximum Hc and Ms of 178.5 Oe and 5.82 emu/ cm3 for 246 nm NiO film, respectively. Density functional theory (DFT) calculations confirmed the experimental results for both single to five layers NiO films and bulk NiO formations. The refined energy gap value was found to be 3.2 eV by the DFT calculation. The films produced at room temperature were found to be stable and reproducible, making them suitable as p-type materials for device construction.Öğe Investigation of magnetic ionic liquids for selective and rapid extraction of gallic acid from complex samples using experimental, statistical modeling and density functional theory studies(Elsevier Sci Ltd, 2024) Fesliyan, Seckin; Maslov, Mikhail M.; Sanaullah; Altunay, Nail; Kaya, SavasGiven the high antioxidant capacity of gallic acid (GA), there is a great deal of interest in the development of rapid, selective, simple, and easily accessible analytical methods for its determination from complex samples. Consequently, the present study aimed to develop an ultrasonic assisted magnetic ionic liquid-based dispersive liquid microextraction (UA-MIL-DLLME) method for the extraction of GA from various samples prior to its spectrophotometric detection. The method's key variables were optimized through statistical analysis. Four magnetic liquids (MILs) were prepared and tested to extract the GA-Se complex formed in aqueous solution. Both experimental studies and theoretical calculations demonstrated that the most suitable MIL for the phase separation of the relevant complex is [P6,6,6,14][Mn(hfacac)3]. The developed UA-MIL-DLLME method exhibited a wide linear range (5-400 ng mL-1), a remarkable enhancement factor (133), and a low limit of detection (1.6 ng mL-1). Additionally, high extraction recovery (97 +/- 1%) with a low relative standard deviation (1.9%) was achieved. The extraction time for the UA-MIL-DLLME method was 8 min. The precision of the method was evaluated through repeatability and reproducibility studies. Finally, the UA-MIL-DLLME method was successfully applied to the extraction of the GA from complex samples using a reference method.Öğe Low-strained carbon monolayers with pentagonal cycles for lithium storage: Precursor analysis, self-assembly simulation and properties prediction(Elsevier, 2025) Katin, Konstantin P.; Kochaev, Alexei I.; Kaya, Savas; Orlov, Konstantin I.; Berezniczcky, Igor, V; Maslov, Mikhail M.We formulated general requirements for hydrocarbon precursors that can easily self-assemble into a defect-free 2D monolayer on a metal substrate by a one-stage process. Based on these requirements, we proposed two suitable precursors contained pentagonal cycles, which were computationally characterized. Classical molecular dynamics shown that they can self-assemble on Cu(111) and Au(111) substrates under ambient conditions, while self-assembly on Ag(111) requires elevated temperature. Probable defect appearing during self-assembly was detected. The resulting 2D monolayers have pores about one nanometer in diameter. Nevertheless, they exhibit high structural stability and metallic conductivity. According to density functional theory calculations, they can be elastically deformed by about 8%, and their elastic constants are comparable to those of graphynes. The presence of pores in the carbon monolayers allows the adsorption of up to 17.2 at. % lithium. Ab initio molecular dynamics confirms the reliable loading of lithium on the monolayers. The presence of pores, absence of highreactive multiple C-C bonds or strained triangle/square cycles as well as excellent adsorption properties are the main advantages of the proposed monolayers in comparison with graphene and its common allotropes.Öğe On point perforating defects in bilayer structures(Royal Soc Chemistry, 2023) Kochaev, Aleksey I.; Efimov, Vladimir V.; Kaya, Savas; Flores-Moreno, Roberto; Katin, Konstantin P.; Maslov, Mikhail M.This article deals with the issue of perforating point defects (pores) in a bilayer heterostructure composed of striped borophene and graphene. Three types of non-equivalent vacancies of the minimum size are considered. These include a single vacancy and two double vacancies. The study of the properties and stability of the perforating defects in borophene-graphene heterostructures is important given the increasing role of such structures in membranes for water purification, renewable energy generation, and other osmotic applications. Using the DFT method, the atomic configurations and main energy characteristics of the proposed defects are obtained. The results show that the formation of a single boron vacancy on the borophene side of borophene-graphene requires less energy than the formation of a carbon vacancy in graphene. Comparisons between double vacancies in nanoscale materials are unreliable because different reference systems produce the different chemical potentials. The problem of choosing the reference system for reliable calculation of the vacancy formation energies is posed and discussed. Using borophene-graphene as an example, it is shown that the reference system strongly affects the magnitude and sign of the vacancy formation energy. Hydrogenation is tested to stabilize the proposed defects. This article deals with the issue of perforating point defects (pores) in a bilayer heterostructure composed of striped borophene and graphene.Öğe Probing of Neural Networks as a Bridge from Ab Initio Relevant Characteristics to Differential Scanning Calorimetry Measurements of High-Energy Compounds(Wiley-V C H Verlag Gmbh, 2022) Bondarev, Nikolay, V; Katin, Konstantin P.; Merinov, Valeriy B.; Kochaev, Alexey, I; Kaya, Savas; Maslov, Mikhail M.The relationships between the theoretical values calculated using density functional theory and experimental data derived from the differential scanning calorimetry of high-energy organic compounds are studied. The theoretical values are the number of atoms and bonds of different types and their lengths, minimum eigenfrequencies, atomization energies, ionization potentials, electron affinities, and frontier orbital energies. The experimental data are the amounts of releasing heat (the first peaks higher than 1 kJ g(-1)) and corresponding temperatures. Neural networks and regression, factor, discriminant, and cluster analysis are applied to find the dependencies between theoretical values and experimental data. It is found that the heat amount cannot be predicted in the general cases, whereas the corresponding temperature can be predicted with a neural network with an accuracy of approximate to 30 degrees C. Cluster and discriminant analysis provides the way for the classification of high-energy compounds into three groups. Some of these groups require particular rules for the prediction of experimental data from the theoretical values.
