Calculations Of Complexes Research Articles

A DFT approach towards therapeutic potential of phosphorene as a novel carrier for the delivery of felodipine (cardiovascular drug)

In this study, Density Functional Theory (DFT) calculations were performed to evaluate the efficiency of phosphorene as a carrier for delivery of felodipine. The felodipine drug, phosphorene carrier, and felodipine-phosphorene complex properties at the ground and excited state were measured to determine the efficacy of phosphorene as a carrier of the cardiovascular drug. The felodipine drug interacts with phosphorene carrier by non-covalent weak interactions. The weak interactions between two components (i.e., phosphorene and felodipine) play a significant role in drug release at a specific targeted site. The excitation from HOMO to LUMO involves the transfer of charge from felodipine to phosphorene which is demonstrated by frontier molecular orbital analysis and further confirmed by Photo-physical results. The excited-state calculation of felodipine-phosphorene complex at CAM-B3LYP/6-31G (d, p) demonstrated that λmax was red-shifted in the gas phase and the solvent phase showed a blue shift. For 1–2 excited states of the felodipine-phosphorene complex, the photoinduced electron-transfer process (PET) was studied. Furthermore, the phosphorene carrier with positive (+1) and negative (–1) charges indicates surface charge analysis and form stable complex systems with felodipine. It is concluded that phosphorene can be used as a carrier for efficient drug-delivery of felodipine drugs.

Interaction of compounds derived from the Chinese medicinal formula Huangqi Guizhi Wuwu Tang with stroke-related numbness and weakness targets: An in-silico docking and molecular dynamics study

Huangqi Guizhi Wuwu Tang (HGWT) is a traditional Chinese herbal formula used for managing post-stroke symptoms. Existing research have supported the use of this formula particularly for stroke-related numbness and weakness (SRNW); however, their mechanisms of actions are not fully understood. This study aims to investigate the molecular mechanisms of components from HGWT targeting specific proteins related to numbness and weakness through computational docking and molecular dynamics (MD) simulations. A total of 786 compounds from HGWT were retrieved from a herbal compound database and docked against a candidate SRNW target protein, with the asernestioside B (HQ068)-mitogen-activated protein kinase 3 (MAPK3) complex predicted to exhibit the highest binding affinity (−10.4 kcal/mol) and number of ligand-receptor contacts. Subsequent molecular dynamics (MD) simulations were performed in triplicate on the apo-MAPK3 protein and asernestioside B -bound form in a solvated system for 200 ns per trajectory to ascertain the stability of the enzyme-ligand complex, and to determine the structural impact of ligand binding. The stability of the complex and overall tertiary structural changes were characterized using root-mean-square deviation (RMSD), radius of gyration (Rg), root-mean-square fluctuation (RMSF) calculations Differences in the RMSF of apo and ligand-bound MAPK3 were most prominent in three major regions: (a) activation loop Asp184:Pro213 (b) MAPK3 insertion site Gly262:Ala291 and (c) loop region at the C-terminus Tyr334:Pro356. Lower values of RMSF for the HQ068-bound protein at the activation loop suggest that HQ068 binding stabilizes MAPK3 in a different conformation in this region compared to the apo protein. Free energy calculations of the asernestioside B-MAPK3 complex revealed key residues contributing to the interaction, which include Pro264, Gln 266, Asp268 and Thr288. These key residues may play an integral role in the binding of selective modulators or substrates of extracellular signal-regulated kinase (ERK) within the MAPK cascade. Overall, this study provides a mechanistic overview of compounds from HGWT. Modelling predicted that asernestioside B may act with high potency against MAPK3, while exhibiting a favourable ADMET profile, and this compound should be explored as a potential agent to alleviate SRNW-related symptoms in future studies.

Synthesis, anti‐proliferative activities, docking studies, and computational calculations of novel isonicotinic mixed complexes

AbstractIn this investigation, we studied the mixing of two ligands, isonicotinohydrazide (L1) and 3‐hydroxyisonicotinic acid (L2), with different metal ions to afford the corresponding stable metal complexes. Consequently, intensive physico‐chemical analysis including elemental analysis, UV–visible, Fourier transform infrared (FT‐IR), thermogravimetric analysis (TGA), mass, 1H nuclear magnetic resonance (NMR), X‐ray diffraction (XRD), magnetic, and molar conductance measurements has been performed. The thermal stability of all complexes was determined using TGA, and the kinetic parameters were obtained using the Coats–Redfern method. Both the degree of crystallinity and the unit cell of all complexes were determined utilizing XRD studies. Furthermore, these metal complexes exhibited excellent anti‐proliferative activity against human breast cancer (MCF‐7) and human liver cancer (HepG2) cell lines against the doxorubicin drug. The Co(II) complex outperformed all other metal complexes in terms of activity, which was confirmed by molecular docking stimulation via the binding energy with amino acids in a structural complex of Kaposi's sarcoma‐associated herpesvirus (KSHV) thymidylate synthase (PDBID:5H38) and the ternary complex of KRIT1 bound to both the Rap1 GTPase and the Heart of Glass (HEG1) cytoplasmic tail (PDBID:4hdq) and shortage. Moreover, these metal complexes were optimized via theoretical investigation through a density functional theory (DFT)/B3LYP/LANL2DZ basis set to confirm the stability of these metals theoretically and detect frontier molecular orbitals (FMO), electrostatic potential (ESP), energy gap, and physical computational calculations. Eventually, the electrochemical features were explored using cyclic voltammetry (CV) and electrochemical impedance spectra (EIS).

Synthesis, characterization, theoretical calculation, DNA binding, molecular docking, anticovid-19 and anticancer chelation studies of some transition metal complexes

The globe has recently been consumed by frightening viral pneumonia (COVID-19). The new strain of the virus, called SARS-CoV-2, belongs to the family of coronaviruses, so research is aimed at screening ligands and drugs for multimodal structure-based structure-design and then docking to the main viral protease to examine the active binding sites. The complexes of Cu(II), Ni(II) Zn(II) and Mn(II) with 3-Cyano-6-(p-chlorophenyl) azo-7-hydroxy coumarin (HL) were synthesized and characterized by elemental analyses, IR, UV-Visible, magnetic measurements and thermal analyses. The measurements of molar conductance showed that all the complexes are non-electrolyte. The IR spectra showed that the ligand (HL) acts as a monobasic bidentate ligand by coordinating via the nitrogen atom (-N = N-) and deprotonated -OH group. Analytical data showed that all complexes exhibited a ratio of 1:1 (metal-ligand). The thermal data indicate that some complexes have outside water molecule and some have within the domain of coordination water molecule, and the complexes display identical fragments of thermogravimetric decomposition that are compatible with the proposed structures. Mass spectra were also used to make the large fragments of the ligand and Ni (II) complex, with the main peaks corresponding to molecular weight using quantum chemical equations.

Assessment of Various Density Functional Theory Methods for Finding Accurate Structures of Actinide Complexes.

Density functional theory (DFT) is a widely used computational method for predicting the physical and chemical properties of metals and organometals. As the number of electrons and orbitals in an atom increases, DFT calculations for actinide complexes become more demanding due to increased complexity. Moreover, reasonable levels of theory for calculating the structures of actinide complexes are not extensively studied. In this study, 38 calculations, based on various combinations, were performed on molecules containing two representative actinides to determine the optimal combination for predicting the geometries of actinide complexes. Among the 38 calculations, four optimal combinations were identified and compared with experimental data. The optimal combinations were applied to a more complicated and practical actinide compound, the uranyl complex (UO2(2,2′-(1E,1′E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene)(CH3OH)), for further confirmation. The corresponding optimal calculation combination provides a reasonable level of theory for accurately optimizing the structure of actinide complexes using DFT.

Spatial search on Johnson graphs by continuous-time quantum walk

Spatial search on graphs is one of the most important algorithmic applications of quantum walks. To show that a quantum-walk-based search is more efficient than a random-walk-based search is a difficult problem, which has been addressed in several ways. Usually, graph symmetries aid in the calculation of the algorithm's computational complexity, and Johnson graphs are an interesting class regarding symmetries because they are regular, Hamilton-connected, vertex- and distance-transitive. In this work, we show that spatial search on Johnson graphs by continuous-time quantum walk achieves the Grover lower bound $\pi\sqrt{N}/2$ with success probability $1$ asymptotically for every fixed diameter, where $N$ is the number of vertices. The proof is mathematically rigorous and can be used for other graph classes.

Reparametrization dependence and holographic complexity of black holes

We refine the calculation of holographic complexity of black holes in the complexity equals action approach by applying the recently introduced criterion that the action of any causal diamond in static vacuum regions must vanish identically. This criterion fixes empty anti--de Sitter (AdS) spacetime as the reference state with vanishing complexity and renders holographic complexity explicitly finite in all the cases we consider. The cases considered here include the Reissner-Nordstr\"om-AdS black hole, the rotating BTZ black hole, the Kerr-AdS black hole, and AdS-Vaidya spacetime. The criterion is equivalent to imposing that the corner contributions vanish. Contrary to earlier results, we find that the generalized Lloyd bound always holds in the Reissner-Nordstr\"om-AdS and BTZ cases.

Synthesis and crystal structure of cytotoxic copper(II) complex with 1,10-phenanthroline-5,6-dione and isothiazole derivative

Oligopyridine based copper(II) complexes are of interest to scientists as possible anticancer agents due to promising cytotoxic and DNA binding/cleaving properties. In this study, copper(II) complex [Cu(phendione)L2]·C2H5OH with 1,10-phenanthroline-5,6-dione (phendione) and 4,5-dichloro-isothiazole-3-carboxylic acid (HL) was synthesized and characterized by elemental analysis, IR-spectroscopy, X-ray powder diffraction and single-crystal X-ray diffraction. According to X-ray diffraction data, obtained compound is mononuclear complex with square pyramidal coordination environment of the central atom which is surrounded by two isothiazolate molecules and one phendione ligand. The X-ray diffraction data are confirmed by IR-spectroscopy data showing the presence of characteristic stretching vibration bands of the carbonyl and carboxyl groups of oligopyridine ligand and isothiazolate ions, respectively. Density functional theory (DFT) calculations for complex were carried out using the ADF software package to perform geometry optimization and frequency calculations that were in a good agreement with experimental IR spectrum. Cytotoxicity of complex and initial reagents was tested in vitro against HepG2 (human hepatocellular carcinoma) and MCF-7 (human breast adenocarcinoma) cell lines. The complex showed high dose-dependent cytotoxic activity with the IC50 values of 0.60±0.03 µM and 0.96±0.13 µM, respectively, which is higher than the activity of cisplatin against these cell lines. The activity of the complex is due to the presence of phendione ligand, which exhibits a similar cytotoxic activity.

АЛГОРИТМ ПРОЕКТУВАННЯ АВТОМАТИЗОВАНИХ ЗМІШУВАЛЬНИХ КОМПЛЕКСІВ БЕЗПЕРЕРВНОЇ ДІЇ ДЛЯ СИПКИХ МАТЕРІАЛІВ

Purpose. Creation of design algorithm of continuous action mixing complexes that will allow defining parameters of the equipment proceeding from requirements to quality, productivity and the set compounding of mixture.Methodology. The method of discrete elements, classical mechanics positions, theory of solids contact interaction, method of mathematical modeling are used in the work.Findings. The paper proposes a generalized algorithm for designing a continuous mixing complex for bulk materials. The procedure for designing a centrifugal mixer, the flow shapers, plate feeders and conical-cylindrical hoppers are presented. Calculations of design and technological parameters are carried out on the basis of information about the physical and mechanical properties of bulk components particles, requirements for equipment performance and the mixture homogeneity. The results of calculations of the mixing complex for the three-component mixture used for the production of polyethylene film are presented. To test the proposed algorithm, a mathematical model based on the discrete elements method is created. The mixing process is modeled and the coefficients of inhomogeneity of each of the components in the finished mixture are determined. The obtained results confirmed that the proposed algorithm allows to determine the parameters of the mixing complex, which ensure compliance with the specified requirements for the quality and the equipment performance.Originality. Mathematical models of bulk motion dynamics in mixing complexes are improved, which include bunker devices, plate feeders, flow shapers and continuous centrifugal mixer, taking into account the bulk motion discrete nature.Practical value. The obtained results allow calculating the design and technological parameters of the equipment that is a part of the continuous mixing complex according to the set productivity, recipe and requirements to the mixture homogeneity.

Synthesis, characterization, biological studies, molecular docking and theoretical calculation of some transition metal complexes with new azo dye 2-[2′-(6-methoxybenzothiazolyl)azo]-3-methyl-4-nitrophenol

Ag(I), Pt(IV), and Au(III) metal complexes of novel ligand 2-[2′-(6-methoxybenzothiazolyl)azo]-3-methyl-4-nitro phenol (6-MBTAMN) have been synthesized and characterized by 1H NMR, 13C NMR, FT-IR, UV–vis, Mass spectra, CHNS, atomic absorption spectrophotometry, molar conductance and magnetic susceptibility. Results confirmed that the ligand coordinates the metal ion to form a mononuclear complex via (N, N, O) atoms of the azomethine group, azo group, and phenolic group, respectively. Tetrahedral geometry is suggested for Ag(I)-Complex, an octahedral geometry is proposed for Pt(IV)-Complex, and a square planar geometry is suggested for Au(III)-Complex. The density functional theory (DFT) was used to calculate significant parameters for ligand and metal complexes, including optimization energy, HOMO, and LUMO. Newly synthesized azo compounds have also been demonstrated to have antimicrobial properties against bacteria and fungi. The complexes are more effective against bacteria than standard antimicrobials (Novobiocin and Cycloheximide), but less effective against fungi. Based on in silico molecular docking, the study demonstrated that the azo fused compounds interact critically with the androgen receptor prostate cancer mutant H874Y ligand binding domain bound with testosterone and an AR 20–30 peptide (ART) using the Molecular Operating Environment module (MOE). Further, the antioxidant activity of novel azo compounds was evaluated using DPPH radical scavenging, which demonstrated that Ag (I) metal complex possess potent antioxidant properties. The cytotoxic abilities of selected compounds by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays against PC3 (human prostate adenocarcinoma) and HUVECs (normal human umbilical vein endothelial cells).

Magnetic Complexity, Magnetodielectric Effect and Dft Calculations on Correlation Driven Gd2comno6 Insulator

Magnetic Complexity, Magnetodielectric Effect and Dft Calculations on Correlation Driven Gd2comno6 Insulator

Development of well complexity calculator and its integration into standard well engineering management system/well delivery system

Oil and gas well drilling is the most important and complex task for oil and gas exploration. It is not necessary that design and execution complexity remain the same for two different wells even in the same field. It is possible to have a very complex well to drill after a very straightforward simple well being drilled earlier in the same field. Making correlation or comparison of any of the two or more than two oil and gas drilling wells is an ongoing debate in the petroleum industry. Generally, companies compare the oil and gas drilling wells on a single or two parameters, for example: time versus depth, directional trajectories, well cost and/or other single factors in disengagement of one another. In order to compare two different types of oil and gas drilling wells, having distinctive design, drilling and fluid program and challenges, a scientific rating system is required, which can relate various wells with one another. In this research paper, a calculator named Well Complexity Calculator has been developed to measure the complexity of the oil and gas well drilling by using different parameters. All these parameters are commonly affecting the drilling program and its execution. Secondly, a methodology is designed for integration of Well Complexity Calculator into standard Well Engineering Management System/Well Delivery System for better execution of drilling program. Fifty-one (51) oil and gas drilling well complexity parameters have been utilized to develop Well Complexity Calculator, where they are categorized into three main complexities types named Design Well Complexity, Geological Well Complexity and Project Well Complexity. Design and Geological Well Complexities combine to form Drilling Well Complexity, and then Drilling Well Complexity and Project Well Complexity combine to form Well Complexity. Median, Mode and Monte Carlo simulation techniques were chosen to develop the calculator where Median showed best suited results and was accordingly chosen for the final calculator. Sixty-six (66) actual oil and gas wells’ camouflaged drilling data were used to analyze and fine tune the developed Well Complexity Calculator. Output complexities of these wells were falling in different complexity levels. Moreover, it was seen that the number of low, high and medium complexity wells was different for Design, Geological, Project, Drilling and Well Complexities which is in line with the real-world scenario.The findings and the output Well Complexity Calculator can be very useful at any stage from initial planning to close-out of a well. Without the application of a system like Well Complexity Calculator, wells are categorized as low, medium or high complexity based on either two to three major parameters or based on qualitative assessment of team involved in the project. Here, step-by-step procedure is developed and explained by which any company involved in Drilling and Well Operations can develop their own Well Complexity Calculator and then accordingly integrate it into their Well Engineering Management System/Well Delivery System.

Synthesis, molecular docking, molecular dynamic, quantum calculation, and antibacterial activity of new Schiff base-metal complexes

The transition metals Co(II) and Cu(II) metal containing Schiff base-metal complexes are highly biological significance molecule for antimicrobial activity, as a result this study has been designed for investigation the synthesis, characterization, in vitro evaluation and in sillico study with molecular dynamic. To kick off, the new Schiff base free ligands, such as L1 and L2, were synthesized from the condensation of nicotinic acid carbohydrazide with vanillin or 2-chloroquinoline-3-carbaldehyde, respectively. The chemical structure of the synthesized Schiff base ligands, and their metal complexes have confirmed their structural geometry by spectroscopic analysis, such as 1H NMR, FTIR and UV-visible spectra, as well as confirming their chemical conversion (4-7) by metalation with the transition metals Co(II) and Cu(II). For evaluation the In vitro study, the antibacterial activity has screened against four human pathogenic bacteria. In addition, for developing the theoretical evaluation of the quantum calculation and biological activity, computational tools were used through the Density Functional Theory (DFT), molecular docking, molecular dynamics and ADMET study. It has revealed that the metal complexes (4-7) illustrate the higher antibacterial activity than the metal free ligands (1-2). The highest antibacterial activity conveys against P. vulgaris among E. coli, S. aureus and B. subtilis through disc diffusion method, and it is near to the standard (Gentamycin) for P. vulgaris. Next, the binding affinity of molecular docking study is more than −6.0 kcal/mol, while the L1-Co (4) shows the highest binding affinity among all bacterial pathogens. The molecular dynamics confirms their ligand-protein complex stability with high range of time (50 ns). Moreover, the Lipinski rule and ADMET properties were evaluated. Finally, the Cobalt complex {L1-Co (4)} shows the higher biological activity in views of both in vitro and computational study.

High-capacity strictly non-blocking optical switches based on new dual principle

In this paper the new dual principle of designing high-capacity strictly non-blocking optical switches is presented for the first time. The new type of switches with decentralized control based on the dual principle has been developed for the first time too. In accordance with the scheme topology this type of switching system was called as the quasi-complete dual switch. It also is analysed the optical signals minimal transmission time that provide the non-blocking property of the new schemes. For the circuit and link complexity calculations the accurate analytical expressions are obtained for the first time. The numerical investigation shows that the proposed schemes significantly benefit in comparison with the well-known switches, for example, the crossbar and Clos schemes. The results of comparing of the dual switch and other types of self-routing switches throughput show an obvious advantage of the proposed scheme. It also is shown that the offered switch type can be considered as a perspective for high-capacity strictly non-blocking optical systems. Indeed, the strictly non-blocking property, the scalability, high throughput, and the decentralized control are the main advantages of offered switches.

Bridging Carotenoid-to-Bacteriochlorophyll Energy Transfer of Purple Bacteria LH2 With Temperature Variations: Insights From Conformational Changes.

Photosynthesis is a key process for converting light energy into chemical energy and providing food for lives on Earth. Understanding the mechanism for the energy transfers could provide insights into regulating energy transfers in photosynthesis and designing artificial photosynthesis systems. Many efforts have been devoted to exploring the mechanism of temperature variations affecting the excitonic properties of LH2. In this study, we performed all-atom molecular dynamics (MD) simulations and quantum mechanics calculations for LH2 complex from purple bacteria along with its membrane environment under three typical temperatures: 270, 300, and 330 K. The structural analysis from validated MD simulations showed that the higher temperature impaired interactions at N-terminus of both α and β polypeptide helices and led to the dissociation of this hetero polypeptide dimer. Rhodopin-β-D-glucosides (RG1) moved centripetally with α polypeptide helices when temperature increased and enlarged their distances with bacteriochlorophylls molecules that have the absorption peak at 850 nm (B850), which resulted in reducing the coupling strengths between RG1 and B850 molecules. The present study reported a cascading mechanism for temperature regulating the energy transfers in LH2 of purple bacteria.

СТУДЕНТОЦЕНТРОВАНІСТЬ КОМП’ЮТЕРНОЇ ПІДТРИМКИ НАВЧАННЯ КОМПЛЕКСНОГО АНАЛІЗУ МАЙБУТНІХ УЧИТЕЛІВ МАТЕМАТИКИ

The article sets forth the author's views on the directions and means of implementing the principles of student-centered approach in the fundamental mathematical education of future mathematics teachers, with the emphasis on computer support as one of the key factors in the formation of digital competence and meeting learning requests and needs of students. The importance of the problem is determined by the need to identify ways to build methodological systems of student-centered education for students of higher pedagogical institutions, in the context of digitalization of educational space and the specifics of the profession and individual disciplines. The authors of the study made an attempt to highlight the theoretical, organizational and technological aspects of the use of the complex number formula calculator CaRevolJet and mathematics computing environment Maple for the complex analysis course in order to develop digital and methodological competencies of future mathematics teachers. The research involved the use of such theoretical and empirical methods as a systematic analysis of scientific and pedagogical sources, European and national recommendations and regulations for the implementation of the updated concept of student-centered learning and the formation of digital competence of the teacher; examination of published materials with insights into pedagogical experience on the research problem; pedagogical observation on the basis of Berdyansk State Pedagogical University (Berdyansk, Ukraine), interviews and surveys of students. The article provides detailed guidelines for the use of CaRevolJet and Maple in solving various types of practical problems of complex analysis, determining the place of this activity in the overall structure of the educational process and establishing links with the future profession. Positive results of approbation of the developed materials in the basic institution of higher education allow determining the prospects of further scientific research in the chosen direction on the basis of what has been achieved. Key words: student-centered learning, future mathematics teacher training, computer support for complex analysis, CaRevolJet, Maple.

Synthesis, crystal structure determination, Hirshfeld surface analysis, spectral characterization, theoretical and computational studies of titanium(IV) Schiff base complex

A titanium(IV) Schiff base complex, [Ti(L)2]·H2O, was synthesized by treating TiO(acac)2 with an ONO-donor Schiff base ligand (H2L) derived from the condensation of 4-aminobenzohydrazide and 3-methoxysalicylaldehyde. The synthesized ligand and its respective complex were characterized by various spectroscopic techniques like FT-IR, 1H NMR, 13C NMR and elemental analysis (CHN). A single-crystal X-ray diffraction (SC-XRD) analysis was also accomplished to ensure the molecular structure of the complex. The geometry around the central metal ion in [Ti(L)2]·H2O was distorted octahedral as revealed by the data collected from diffraction studies. Hirshfeld surface analysis showed that H…H interatomic contact is the most significant contributor to the crystal packing of the complex. Moreover, theoretical calculations of the Schiff base complex were carried out by DFT at the B3LYP/Def2-TZVP level of theory, which showed a good correlation with the experimental findings.

A reconsideration on the resolution of phase stability analysis using stochastic global optimization methods: Proposal of a reliable set of benchmark problems

Phase stability analysis is an important thermodynamic calculation in the context of process systems engineering of multiphase units (e.g., separation systems, reactors). It implies the minimization of the Tangent plane distance function (TPDF), which has been recognized as a challenging global optimization problem. Despite the importance of this thermodynamic calculation, the characterization and classification of resolution complexity of phase stability problems that are commonly used to test and compare global optimization methods have not been addressed in literature. This paper reports the first step to propose a set of benchmark TPDF problems to assess and identify the advantages and limitations of stochastic optimization methods used in phase stability calculations. A detailed review of TPDF problem reported in literature was performed and the most representative ones were studied and classified in terms of their resolution complexity via the analysis of several performance metrics associated to both reliability and efficiency to find the global TPDF minimum. Differential Evolution, Simulated Annealing, Harmony Search, Tabu Search, Particle Swarm Optimization and Genetic Algorithm were selected as the metaheuristics to perform the global minimization of selected TPDF problems. 35 phase stability problems were classified in low, medium and high difficulty TPDF problems. Results showed that, although a wide variety of phase stability problems has been reported and used for phase stability calculations, a significant number of them corresponded to global optimization problems of easy resolution. Therefore, some authors have reported biased conclusions on the performance of stochastic optimization methods. A set of 23 TPDF was proposed as benchmark problems to obtain a reliable analysis of the numerical performance of metaheuristics employed in phase stability calculations. This benchmark set contains problems with different resolution difficulties and characteristics that are considered appropriate to study and assess new methods to resolve the global TPDF optimization, as well as to improve the existing methods. This paper highlights the relevance of a continuous development and improvement of stochastic global optimizers for solving, robustly and efficiently, the phase stability analysis in multicomponent systems. TPDF minimization can be still considered a challenging problem to be faced in the context of applied thermodynamics.

Tuning optical and electronic properties of graphene oxide by surface adsorption of molecular halogens (X2 = I2, Br2, Cl2, and F2) for light harvesting

Surface adsorption of small molecules modulates both optical and electronic structure, which is beneficial for different applications. The molecular adsorption of halogens X2 (X2 = I2, Br2, Cl2, and F2) was investigated using density functional theory and the dispersion (Wb97xd) module. The electronic structure and optical properties of the pristine graphene oxide (GO) and its molecular complexes with halogens (GOI2, GOBr2, GOCl2, and GOF2) are explored. The adsorption of X2 (X2 = I2, Br2, and Cl2) molecules were stabilized by non-covalent lone pair-π bonding, (O)lp… π, interactions and π-π interactions. The F2 molecule were stabilized by lone pair-π bonding, (O)lp… π, as well as halogen bonding (XB). The GOX2 complexes were energetically stable and optically red shifted in polar solvents. The simulated optical absorption spectra at TD-DFT calculations of GOX2 complexes and TDOS uncover the presence of intermediate sates in the energy gap region, which is beneficial for harvest of visible light and photocatalysis.

Interpretation of multiple solutions in fully iterative GF2 and GW schemes using local analysis of two-particle density matrices.

Due to the presence of non-linear equations, iterative Green's function methods can result in multiple different solutions even for simple molecular systems. In contrast to the wave-function methods, a detailed and careful analysis of such molecular solutions was not performed before. In this work, we use two-particle density matrices to investigate local spin and charge correlators that quantify the charge resonance and covalent characters of these solutions. When applied within the unrestricted orbital set, spin correlators elucidate the broken symmetry of the solutions, containing necessary information for building effective magnetic Hamiltonians. Based on GW and GF2 calculations of simple molecules and transition metal complexes, we construct Heisenberg Hamiltonians, four-spin-four-center corrections, and biquadratic spin-spin interactions. These Hamiltonian parameterizations are compared to previous wave-function calculations.