Density Functional Theory Method Research Articles

Studying the optical and electronic properties of Eu-doped CdSe phosphors using first principles calculations incorporating the spin orbit coupling method of DFT

We studied the electronic and optical properties of pure and Eu-doped CdSe phosphor materials using the first-principles calculation method, which is a feature of Density Functional Theory. The FP-LAPW method was employed for the study as incorporated in the Wien2k code. The GGA + U + SOC method of DFT was used for the first time in our study to investigate the electronic as well as optical characteristics of Eu-doped CdSe materials. Eu doping was done in two different ratios to study the effects of altered dopant concentration. The doping increased the band gap of the pure CdSe parental material. The calculated band gaps in our study were 0.42 eV for pure CdSe, 0.67 eV for a single Eu atom doped in CdSe, and 1.64 eV for two Eu atoms doped in CdSe. The measured electronic and optical characteristics of undoped i.e, pure CdSe and Eu-doped CdSe showed that the doping significantly changed the optical behavior of CdSe, which may be useful for applications in phosphor-converted LEDs.

Interaction between Molnupiravir and noble metal substrates in SERS detection: A DFT method and Raman characteristic study

Molnupiravir, a nucleoside analogue (EIDD-2801), is an RNA polymerase inhibitor that effectively treats infections caused by novel coronaviruses and can be administered orally. Therefore, it is necessary to monitor the distribution of Molnupiravir in vivo after oral administration. Surface-enhanced Raman spectroscopy (SERS) is a suitable detection method, so it is necessary to understand the interaction between Molnupiravir and noble metal nanoparticles in the SERS effect. Therefore, we used density functional theory combined with surface-enhanced Raman spectroscopy to investigate the interaction between Molnupiravir and noble metal/composite nanoparticles in the SERS effect. To study the interaction sites of Molnupiravir and the substrate in the SERS effect, the molecular electrostatic potential (MEP) of Molnupiravir was calculated. Considering the significant role of binding energy in studying molecular docking, the binding energy between Molnupiravir and Metal6 (Au6, Ag6, Au3Ag3) atomic clusters was calculated. The calculated results of the frontier orbitals and relevant molecular parameters of Molnupiravir and Molnupiravir-Metal6 complexes reveal the changes in the molecular properties of Molnupiravir in the SERS effect. Finally, the theoretical Raman spectra differences between Molnupiravir and complexes were compared and analyzed, and the adsorption structure of Molnupiravir on the substrate surface was determined based on the surface selection rules of SERS. The research results will provide insights into the interaction between Molnupiravir and the substrate in the SERS effect, and also offer theoretical support for the application of SERS methods in biomedical detection.

Triple Inhibition of SARS‐CoV‐2 by Rhenium(I) Acetylacetonato Tricarbonyl Phosphine Complexes: Structural Features, DFT Calculations, HS Analysis and In Silico Molecular Docking Study

AbstractTo gain insights into the activity of metal‐based drugs against SARS‐CoV‐2, five rhenium complexes, namely fac‐[Re(CO)3(acac)(PPh2Cy)] (I), fac‐[Re(CO)3(acac)(PPhCy2)] (II), fac‐[Re(CO)3(acac)(PCy3)] (III), fac‐[Re(CO)3(acac)(P(m‐tolyl)3)] (IV), and fac‐[Re(CO)3(acac)(P(p‐tolyl)3)] (V), with acac=acetylacetonato, PPh2Cy=cyclohexyldiphenylphosphine, PPhCy2=dicyclohexylphenylphosphine, PCy3=tricyclohexylphosphine, P(m‐tolyl)3=tri(m‐tolyl)phosphine, and P(p‐tolyl)3=tri(p‐tolyl)phosphine, were docked in the binding pockets of main protease, spike glycoprotein, and RNA‐dependent RNA polymerase. The resulting binding sites revealed potent SARS‐CoV‐2 inhibition, resulting from the formation of classical N−H⋅⋅⋅O and O−H⋅⋅⋅O hydrogen bonds, carbon C−H⋅⋅⋅O H‐bonds, hydrophobic contacts, as well as non‐conventional interactions such as weak C−H⋅⋅⋅N interactions, H⋅⋅⋅H, C⋅⋅⋅H/H⋅⋅⋅C, C⋅⋅⋅lp/lp⋅⋅⋅C and lp⋅⋅⋅lp contacts, cation‐π interactions and π⋅⋅⋅π stacking in the targets’ binding pockets. Moreover, we have optimized the molecular structures of these compounds using DFT methods and correlated them correspondingly to their crystal structures. We have estimated and evaluated the associated frontier molecular orbitals, as well as the global reactivity descriptors for which we have discussed the compounds’ reactivity. We have also examined intermolecular interactions by carrying out a Hirshfeld surface (HS) analysis, which showed the presence of C−H⋅⋅⋅H−C, C−H⋅⋅⋅C interactions, C−H⋅⋅⋅O non‐classical hydrogen bonds and π⋅⋅⋅π stacking, as well as non‐conventional π⋅⋅⋅lp and lp⋅⋅⋅lp interactions.

Structure and noncovalent interaction analysis of half-sandwich chiral-at-metal organoruthenium complexes with planar and η6-arene-metal axial chirality

The preparation of organometallic compounds has provided new molecular complexity in molecular science. The stereochemistry of organometallics has long been a great challenge due to the large atom radius and more valency. Herein, eight ruthenium piano-stool shaped Ru complexes 2a-d and 3a-d with η6-planar chirality and Ru-center chirality were successfully synthesized and resolved, and the absolute configurations were determined by X-ray diffraction analysis. Racemization experiment revealed the stability differences of the Ru complexes in various solvents. Furthermore, in asymmetric unit of complex 3b, there are two conformers bearing opposite η6-arene-Ru axial chirality. In the supramolecular organization, all of the Ru complexes are stabilized by hydrogen bonding, C-H···π and Cl/I···π interactions. π···π interaction was only observed in complex 3b. The Hirshfeld surface analysis and 2D fingerprint plot show that the eight complexes have a similar contribution composed of different noncovalent interactions to the stabilization of crystal packing. Interestingly, only complex 3b has 3.5% C···C interaction. The pairwise interaction energies were calculated using CE-B3LYP energy model and further visualized by 3D-energy framework, which show that the dominant interaction for all complexes is dispersion. Theoretical energies of each conformer of complex 2a-d and 3a-d with η6-arene rotated at different angles was calculated by DFT method, and the energy barrier between the two conformations was around 2-3 kcal/mol. Halide ligand exchange experiments on complex (SRu)-1a were performed and the plausible mechanism was proposed. These results have provided new evidence for the design of molecules with specific fine stereochemical information for potential applications in medicinal and material chemistry.

The electronic and optical properties of group III-V semiconductors: Arsenides and antimonides

Investigating the structural, electronic, and optical properties of zinc-blende III-V semiconductors, particularly arsenides, and antimonides, which are crucial for optoelectronic devices such as transistors, infrared detectors, and quantum technologies due to their wide range of direct bandgaps. In this work, we have employed a first-principles approach integrating G0W0 with the HSE06 hybrid functional and spin–orbit coupling (SOC) to study their fundamental properties. Traditional Density Functional Theory (DFT) methods, particularly those using Generalized Gradient Approximation (GGA) PBE functionals, tend to underestimate bandgaps, leading to discrepancies with experimental results. To address this, our study corrects the bandgap underestimation and refines the calculation of optical constants, including the dielectric function, refractive index, extinction coefficient, and absorption coefficient. Moreover, the optimized lattice constants and electronic properties derived from our computational model strongly correlate with experimental data, demonstrating the model’s reliability in predicting material properties. The findings suggest that our methods can be applied to arsenides and antimonides, offering a pathway to designing materials with optoelectronic properties involving III-V compounds and their complex heterostructures for advanced device applications.

Theoretical Investigation of Energetic Materials Based on Imidazole Framework Featuring Azido/Nitro/Nitrato/Fluoro Groups

ABSTRACTDevelopment of new high‐energy materials (HEMs) is one of the thrust areas of research. These compounds are important for various applications such as propellants, gas generations, explosives in mining, construction, civil and military applications, and safety equipment for national security and defense. HEMs based on imidazole frameworks are currently getting research spotlight due to their exceptional detonation performance with optimum sensitivity. This study reports five imidazole derivatives containing azido/nitro/nitrato/fluoro functional groups. These groups are viable options to design promising explosives with moderate sensitivity. Density functional theory (DFT) method is adopted to determine the geometries, thermodynamic properties, detonation properties, and impact sensitivity of the designed molecules. All the compounds have high density in the range of 1.89–2.03 g/cm3 along with high heat of formation. These compounds aid in new strategy to design HEMs with optimum sensitivity.

Dataset for carbon dioxide adsorption on lizardite

This paper presents data on the adsorption of CO2 on the (001) and (00 ) surface lizardite. The data were obtained from calculations using the density functional theory (DFT) method implemented in the CASTEP software package. The calculations were performed using the plane wave basis set and the Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional. A semi-empirical Grimme D2 correction was used to correctly account for dispersion interactions, which play an important role in physical adsorption processes. The data include optimized geometry and electronic properties of equilibrium states of adsorbed CO2 on (001) and (00 ) lizardite surfaces. They contain the most energetically favorable adsorption sites and estimates of the interaction strength between the adsorbate and adsorbent. The analysis of the electronic structure includes calculations of charge distribution, density of states (DOS), and visualizations of electron density difference isosurfaces. These data provide detailed insights into the redistribution of electron density during adsorption and the nature of the bonds formed. All data, including optimized crystal structures, electronic properties, and calculation results, are available in formats that can be read by commonly available text editors and specialized atomic structure visualization and analysis software. The presented dataset can serve as a foundation for further studies on the interactions of various molecules with the lizardite surface.

Computational Study on the Inhibition Mechanisms of the Ziegler-Natta Catalyst in the Propylene Polymerization Process: Part 1 Effects of Acetylene and Methylacetylene

Acetylene and methylacetylene are impurities commonly found in the raw materials used for the production of polymers such as polypropylene and polyethylene. Experimental evidence indicates that both acetylene and methylacetylene can decrease the productivity of the Ziegler-Natta catalyst and alter the properties of the resulting polymer. However, there is still a lack of understanding regarding the mechanisms through which these substances affect this process. Therefore, elucidating these mechanisms is crucial to develop effective solutions to this problem. In this study, the inhibition mechanisms of the Ziegler-Natta catalyst by acetylene and methylacetylene are presented and compared with the incorporation of the first propylene monomer (chain initiation) to elucidate experimental effects. The Density Functional Theory (DFT) method was used, along with the B3LYP-D3 functional and the 6-311++G(d,p) basis set. The recorded adsorption energies were −11.10, −13.99, and −0.31 kcal mol−1, while the activation energies were 1.53, 2.83, and 28.36 kcal mol−1 for acetylene, methylacetylene, and propylene, respectively. The determined rate constants were 4.68 × 1011, 5.29 × 1011, and 2.3 × 10−8 M−1 s−1 for acetylene, methylacetylene, and propylene, respectively. Based on these values, it is concluded that inhibition reactions are more feasible than propylene insertion only if an ethylene molecule has not been previously adsorbed, as such an event reinforces propylene adsorption.

Effect of the RhnNin alloy cluster size on the catalytic performance of RhnNin/TiO2 in the conversion of syngas to ethanol

The direct conversion of syngas to ethanol on the RhnNin/TiO2 (n = 1, 2, 3, 4) catalyst has been investigated by using the density functional theory (DFT) and micro-kinetic methods, in order to elucidate the regulatory mechanism of RhnNin alloy cluster size-induced metal-support interaction on the catalytic performance of RhnNin/TiO2 in the ethanol synthesis. The results indicate that Rh1Ni1/TiO2 and Rh3Ni3/TiO2 can significantly enhance the conversion of CO and the formation of C–C bond and meanwhile inhibit the generation of methane. Rh1Ni1/TiO2 exhibits the highest ethanol production activity and relative selectivity. The electronic property analysis results suggest that Ni atoms on the alloy clusters and Ti and O atoms on the supports transfer the most charge to the Rh atoms on the Rh1Ni1/TiO2 catalyst, which displays the strongest Rh-Ni interaction on the alloy clusters as well as the strongest interaction between the alloy clusters and the TiO2 support, endowing Rh1Ni1/TiO2 with the highest catalytic activity. In addition, the Ab-initio molecular dynamics (AIMD) simulations at 525 K show that the Rh1Ni1/TiO2 catalyst has high thermal stability.

Performance Study and Application of Antioxidant Peptides CHCIWM and CHCPWM

AbstractWhen the level of reactive oxygen species (ROS) increases abnormally in the body, it damages tissue cells and is closely related to the occurrence of various chronic diseases. Antioxidant peptides (APs) are a class of active short peptides with antioxidant capacity, which have great research value. In this paper, two APs were designed and synthesized based on the structural features of APs: CHIWM (AP1) and CHCPWM (AP2). The reactive sites and activities of APs were analyzed using the quantum chemical density functional theory (DFT) method. The reactive sites are all located in the indolyl heterocycle of tryptophan residues, among which AP1 has a smaller energy gap and single point energy. Multiple free radical scavenging assays showed that AP1 and AP2 had stronger antioxidant activity than the positive control, glutathione (GSH). For scavenging DPPH free radicals, the IC50s values were 0.613 mg/mL and 0.606 mg/mL, respectively. In cellular assays, both AP1 and AP2 were able to scavenge ROS in the cells and attenuate cellular damage. In conclusion, AP1 and AP2 designed in this paper have good antioxidant activity and have the potential to be applied in the treatment of chronic diseases caused by cellular oxidative damage.

Unravelling heterogenous adsorption performance of hydrochar particle and key properties in heavy metal immobilization relative to corresponding residual bulk hydrochar

Immobilization performance of released hydrochar particle (HP) to metal is largely unknown and hinder accurate estimation to immobilization effect in hydrochar application. Herein, HPs derived from typical biomass, food waste (FW), and blue algae (BA), were collected to investigate their adsorption abilities, mechanisms towards typical Cd(II) relative to residual bulk hydrochar (BH) and unravel corresponding properties of this heterogeneity. The results were: 1) the micro-sized HP with poor porous structure, less O-containing functional groups (OFGs) and negative surface charge induced inferior adsorption capacities (0.65-0.81 times) but quicker adsorption rate (3.09-10.08 times) towards Cd(II) compared with BH, 2) cation bridge interaction in coagulation and settling processes unexpectedly facilitated adsorption performance of micro-sized and negative charged FWHPs added with counterions, 3) HP facilitated its electrostatic attraction with Cd(II) rather than common pore filling and surface complexation, especially bare aromatic structure in HP formed another cation-π interaction with Cd(II) highlighted by density functional theory (DFT) method. The special coagulation process and cation-π interaction of HP will facilitate its vertical co-migration ability but weaken immobilization stability towards metals. The distinct heterogeneities of adsorption ability of HP and BH and underlying key properties provide an in-depth understanding of hydrochar application for remediation of metal contaminants in soil/water environment.

Anti-inflammatory and anticancer activities of boron nitride nanotubes functionalized with curcumin: Density functional theory and molecular docking studies

Boron nitride (BN) nanotubes have emerged as promising carrier options for drug delivery systems. This study investigates the loading of curcumin (CUR) in various states onto the surface of a zigzag (8, 0) boron nitride nanotube, which consists of 8 unit cells, has a diameter of approximately 6.66 Å, and a length of approximately 20 Å, in order to enhance its solubility and stability. The assessment utilizes density functional theory (DFT) methods with the PBE1-D functional and 6-311G** basis set in a solvent (water) phase. It was found that the CUR, via its carbonyl group in compound A (−1.37 eV), can be electrostatically interact with the center of BNNT surface compared to compound B (−0.84 eV) and compound C (−1.12 eV). During the adsorption process, compound A exhibited the highest increase in dipole moment, with a value of 16.84 Debye, followed by compound C with 15.99 Debye, and compound B with 13.03 Debye, suggesting enhanced solubility of the system. The results indicate that the hardness, softness, and electrophilicity values of compounds A, B, and C decrease upon CUR adsorption, implying that CUR enhances the reactivity of BNNT. Additionally, the conductivity of the BNNT is affected by changes in the energy gap when CUR is adsorbed onto the outer surface of the nanotube. The molecular docking results of the TNF-α receptor revealed that complex B exhibited the lowest binding energy (−10.8 kcal/mol) and optimal orientations toward the receptor, suggesting a strong binding affinity. Conversely, complex C (−10.1 kcal/mol) demonstrated significant binding affinity to the NF-KB target, indicating its potential as an effective NF-KB inhibitor. Therefore, BNNTs could serve as templates for the design and synthesis of innovative anti-inflammatory agents with potent anticancer properties.

Theoretical insights of 2D Fe3GeTe2/In2Se3 multiferroic vdW heterostructure based gas sensors for high-performance NO detecting

The impact of the harmful gas NO on the atmospheric environment cannot be ignored, so it is necessary to develop efficient gas sensors to detect and absorb NO at room temperature. In this work, we systematically explored the electron transport properties and gas sensing properties of Fe3GeTe2, In2Se3 monolayers and its multiferroic van der Waals (vdW) heterostructures of Fe3GeTe2/In2Se3 for detecting NO by using density functional theory and nonequilibrium Green's function methods. The calculated adsorption energies, electron localisation functions, band structures and density of states indicate that its a chemisorption for the adsorption of NO on Fe3GeTe2 and a physisorption on In2Se3, while the specific adsorption style is highly dependent on the stacking and molecular adsorption sites of different Fe3GeTe2/In2Se3 structures. In addition, the pristine Fe3GeTe2 monolayer and Fe3GeTe2/In2Se3 based nanodevices realized a significant anisotropy for electron transport along the zigzag and armchair directions, and their anisotropic maximum current ratios in the zigzag to armchair directions were 1.90 and 1.89. Meanwhile, the NO sensitivity ratio of Fe3GeTe2 and Fe3GeTe2/In2Se3 based gas sensors can be up to 79 % and 107 %, respectively. This highlights a notably superior gas-sensitive performance of the Fe3GeTe2/In2Se3 heterostructure compared to the Fe3GeTe2 monolayer gas devices. These findings provide valuable references for the application of multiferroic heterostructures in the field of gas sensors.

Insights into the Adsorption Mechanism of Chlorpyrifos on Activated Carbon Derived from Prickly Pear Seeds Waste: An Experimental and DFT Modeling Study

The removal of chlorpyrifos (CPF) from water was achieved using activated carbon (AC) derived from prickly pear seeds (PPS) wastes, developed through chemical activation with phosphoric acid. Several physico-chemical characterization methods were employed. The determination of surface functions using the Boehm assay indicated that the processed AC predominantly possesses acidic functions. The results obtained from the Boehm assay were corroborated by the pH value of the point of zero charge (pHpzc), which was equal to 2.5. Specific area calculation by the BET (Brunauer Emmett Teller) method revealed a large specific area (SBET) of 1077.66 m2 g⁻1. Adsorption experiments of CPF on AC demonstrated that the pseudo-second order (PSO) model and the Freundlich model were the most suitable for kinetic and isothermal modeling, respectively. The maximum CPF adsorption capacity of the PPS AC was found to be approximately 35 mg g⁻1. A theoretical study employing the density functional theory (DFT) was conducted using the B3LYP/6-311G (d, p) method. The most reliable adsorption energy (Eads) and Gibbs free energy (ΔGads) values between CPF and the functional groups on the AC surface were calculated. Results indicated a strong interaction between the lactone group of AC and CPF (ΔGads = -7.15 kcal mol⁻1, ΔEads = -21.55 kcal mol⁻1) and the hydroxyl group (ΔGads = -6.61 kcal mol⁻1, ΔEads = -20.66 kcal mol⁻1). This study demonstrates that activated carbon possesses significant adsorption power, making it highly effective for depolluting water contaminated by pesticides. The application of the theoretical DFT method enhances the understanding of the adsorption phenomenon of CPF on AC.

Tuning optoelectronic properties of indandione-based D-A materials by malononitrile group acceptors: A DFT and TD-DFT approach.

Indandione-based materials are promising candidates for organic electronics, offering high electron mobility and tunable optoelectronic properties. In this study, we explore the optoelectronic and photovoltaic properties of indandione-based donor-acceptor (D-A) materials, specifically (R1) and (R2), by introducing malononitrile group acceptors into their molecular structure. These strong electron-withdrawing acceptors are designed to enhance charge transfer and overall material performance. The designed molecules (DM1-DM4) exhibit a low optical band gap of approximately 1.77eV, significantly lower than the reference materials (R1 and R2) at around 2.24eV in a solvent environment. Among the designed molecules, DM4 stands out with superior photovoltaic parameters, including a narrow optical band gap (1.77eV), higher electron affinity (3.49eV), an extended excited state lifetime (10.0ns) owing to its low electron and hole reorganization energies (λe ~ 0.13eV and λh ~ 0.24eV), and improved short-circuit current density (Jsc) of ~ 15.73mA/cm2. Notably, DM4 achieves a power conversion efficiency (PCE) of ~ 18.5%, making it an excellent candidate for device applications. A comprehensive computational investigation was carried out on indandione-based D-A materials with malononitrile group acceptors (DM1-DM4) using density functional theory (DFT) and time-dependent DFT (TD-DFT) methods, as implemented in Gaussian 16 software. We examined the electronic and optical properties of the proposed molecules through frontier molecular orbital (FMO) analysis, UV-Vis absorption spectra, density of states (DOS), exciton binding energy (Eb), and transition density matrix (TDM) analysis, utilizing GaussView 6.0 and Multiwfn 3.8 software. The photovoltaic parameters and power conversion efficiency (PCE) were evaluated using the Scharber and Alharbi models.

Structural and Electronic Properties of U5M+ and T5M+ (U = Uracil, T = Thymine, M = Ag and Au) Cluster Cations

The geometric and electronic structures and the bonding of U5M+ and T5M+ (U = uracil, T = thymine, M = Ag, Au) cluster cations have been investigated with density functional theory methods. They have a perfectly planar structure with C5h symmetry and significant stability, containing self-complementary N-H···O hydrogen bonds and five Au-O or Ag-O contacts. The energy gap between the LUMO and HOMO in the U5Ag+ cluster is 4.2 eV, which is twice as large as the HOMO-LUMO gap observed in the U5Au+ cluster. This notable difference clearly indicates that the U5Ag+ cluster possesses substantially greater stability compared to the U5Au+ cluster. This finding is consistent with the results from the energy decomposition analyses, which show that the total interaction energy of U5Ag+ is significantly higher than that of U5Au+. The same trend is observed in T5M+ as well. The interaction between the metal atoms, whether gold (Au) or silver (Ag), and the nucleobase is not predominantly controlled by electrostatic forces, as initially believed. Instead, it is primarily characterized by pronounced covalent bonding effects.

Optimal donor groups for novel organic dye “3-(5-(4-(diphenylamino)styryl)thiophen-2-yl)-2-cyanoacrylic acid” in the context of N‑type dye-sensitized solar cells: A theoretical investigation

Theoretical modeling using DFT and TDDFT methods explored optimal donor groups for the organic dye “3-(5-(4-(Diphenylamino)styryl)thiophen-2-yl)-2-cyanoacrylic Acid”. Seven different moieties and their derivatives mostly used as donors as obtained from the literature (methylamine, benzene, fluorene, carbazole, phenylaniline, indolizine and pyrrolizine) were investigated, and our calculations highlighted indolizine and pyrrolizine derivatives as the most effective donors among those studied. The strong push pull effect of such derivatives of indolizine and pyrrolizine groups played a role in enhancing the efficiency of the dye sensitizers.

A new activity model for biotite and its application

A new activity model for biotite is formulated in the system K2O-FeO-MgO-Al2O3-SiO2-H2O-TiO2-O2 (KFMASHTO), which extends that for the KFMASH system by introducing a titanium-biotite and a ferric-biotite end-member (tbio: K(TiMg2)[(O)2(AlSi3)O10] and fbio: K(Fe3+Mg2)[(OH)2(Al2Si2)O10]), as well as a pyrophyllite end-member (pyp: Al2[(OH)2Si4O10]) that accounts for the presence of octahedral excess-Al in natural biotites. Phonon calculations applying density functional theory (DFT) using the software Castep yielded the standard entropies of tbio and fbio as Sotbio = 328.06 J/(mol·K) and Sofbio = 301.69 J/(mol·K), and their heat capacity functions. From experimental phase-equilibrium data, the enthalpy of formation value of tbio was constrained as ΔHf,tbioo\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {H}_{f,tbio}^{o}$$\\end{document} = −6124.68 ± 3.33 kJ/mol. Natural data were used to derive ΔHf,fbioo\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta {H}_{f,fbio}^{o}$$\\end{document}= −5935.3 ± 6.6 kJ/mol. The single-defect DFT method was applied to parameterize important macroscopic mixing properties (macro-W’s) involving tbio and pyp end-members in the model (fbio was treated ideal). Castep-derived microscopic interaction energies (micro-w’s) are presented herein for KFMASH-biotite. The octahedral same-site (M1) Mg–Al mixing micro-w (wMgAl(M1)), the same-site tetrahedral Si-Al mixing parameter (wSiAl(T1)) and the related cross-site term are: wMgAl(M1) = 82.5 kJ/mol, wSiAl(T1) = 95.6 kJ/mol (two T1-sites) and wMgAlAlSi(M1T1)=\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${w}_{MgAlAlSi(M1T1)}=$$\\end{document} 175.1 kJ/mol. The linear combination of these micro-w’s gives a macroscopic Wphleas = 18.8 kJ/mol, that is not transferable to other mineral groups. Micro w’s for Mg-Fe mixing in biotite (wMgFe(M1), wMgFe(M2),wMgMgFeFe(M1M2)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${w}_{MgMgFeFe(M1M2)}$$\\end{document}), are all close to ideality. The biotite activity model of this study is thus a first example of next-generation activity models that use DFT- and thus physically based micro-w’s and reassembled macro-W’s for petrological calculations. Test calculations on 5 samples from low- to high-grade metamorphic environments covering metapelite to greywacke bulk-compositions using Perple_X suite of programs illustrate the performance of the new biotite activity model. Computed mineral-chemistries are in all cases in better agreement with measured compositions than resulting from published activity models of biotite.

Systematic Exploration of the Interactions between Pyrite and Coal from the View of Density Functional Theory

Coal is often adhered to by pyrite during slime flotation, causing an increase in the sulfur content of clean coal. In order to study the mechanism of pyrite adhesion to coal surfaces, different coal structural units were built and optimized, and the most stable adsorption model of them on pyrite surfaces was determined. The mechanism of pyrite particles adhering to the surface of coal slurries was explored with the method of DFT. The results showed that the interaction mechanism between pyrite surface and Ph-OH and Ph-O-CH3 was the result of a weak interaction between the H atom of Ph-OH and Ph-O-CH3 and the S atom of the pyrite surface. The interaction mechanism between the pyrite surface and Ph-COOH and Ph-CO-CH3 was both as a result of H-S interactions and weak Fe-O interactions. On the whole, there were weak interactions between pyrite particles and the coal slurry, and the pyrite particles can spontaneously adsorb on the surface of the coal slurry.

Unraveling quantum capacitance of black phosphorene by the doping of non-metals for energy storage applications using DFT method

Supercapacitor plays a pivotal role as energy storage devices in the context of eliminating energy resources. Black Phosphorene (BP) is highly regarded as a potential electrode for supercapacitor (SC) because of its outstanding properties, including excellent carrier mobility and unique electronic properties. In this research work, the monolayer of BP and bilayer of BP (BP/BP) structure is investigated by using DFT. Moreover, the effect of doping and co-doping of non-metal (oxygen, nitrogen) in the mono- and bi-layer was also investigated to increase their performance by modulating the charge storage, and electronic properties of BP. The structural properties, density of states, quantum capacitance, surface charge density, bader charge analysis, isosurface charge density difference, integrated charge density of monolayer and bilayer are studied. The density functional theory (DFT) is used to calculate all above mention properties. DFT-D3 method with Becke-Johnson damping function is used as dispersion correction factor for all the calculations of bilayer. The calculated results find that bilayer structure gives better results as compared to monolayer structure. In this work, results also revealed that doping of oxygen and nitrogen atom significantly enhance the CQ and Q of mono- and bi-layer structure. For aqueous system, all the composites exhibited asymmetrical behavior except BP/BP bilayer. BP-N/BP-N (1369.8µC/cm2), and BP-O/BP-O (-1298.1µC/cm2) bilayer structure are best for anode and cathode material. In case of ionic/organic system, all composites showed asymmetrical behavior. BP-O/BP-O (-6053.5µC/cm2), and BP-N/BP-N (9329.8µC/cm2) bilayer structure is best cathode and anode material.