scholarly journals An investigation on the structures of Sc2B8 clusters by a combination of the genetic algorithm and density functional theory (GA-DFT) and its CO-adsorption

2021 ◽  
Vol 10 (2) ◽  
pp. 64-70
Author(s):  
Thao Nguyen Minh ◽  
Tram Nguyen Thi Ngoc ◽  
Huong Nguyen Thi Lan ◽  
Thanh Bui Tho
Keyword(s):  
Genetic Algorithm ◽  
Density Functional ◽  
Local Minimum ◽  
Global Minimum ◽  
Structural Parameters ◽  
Co Adsorption ◽  
Relative Energy ◽  
Adsorption Method ◽  
Functional Theory ◽  
Boron Cluster

The structures of Sc2B8 were investigated by a combination of genetic algorithm (GA) with PBE functional (GA-DFT). Its CO-adsorption were studied by calculations with PBE functional. Many structures include local minimum and global minimum structures were determined. The structural parameters, relative energy, energetic properties, dissociation energy were reported. Results indicated that CO molecule can be adsorbed at many positions of these clusters. Scandium doped boron cluster can be used to produce materials that can treat CO gas by adsorption method.

scholarly journals Effects of Temperature on Enantiomerization Energy and Distribution of Isomers in the Chiral Cu13 Cluster

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5710
Author(s):  
Cesar Castillo-Quevedo ◽  
Carlos Emiliano Buelna-Garcia ◽  
Edgar Paredes-Sotelo ◽  
Eduardo Robles-Chaparro ◽  
Edgar Zamora-Gonzalez ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Density Functional ◽  
Room Temperature ◽  
Global Minimum ◽  
Energy Surface ◽  
Energy Structure ◽  
Density Functionals ◽  
Free Energy Surface ◽  
Functional Theory ◽  
Effects Of Temperature

In this study, we report the lowest energy structure of bare Cu13 nanoclusters as a pair of enantiomers at room temperature. Moreover, we compute the enantiomerization energy for the interconversion from minus to plus structures in the chiral putative global minimum for temperatures ranging from 20 to 1300 K. Additionally, employing nanothermodynamics, we compute the probabilities of occurrence for each particular isomer as a function of temperature. To achieve that, we explore the free energy surface of the Cu13 cluster, employing a genetic algorithm coupled with density functional theory. Moreover, we discuss the energetic ordering of isomers computed with various density functionals. Based on the computed thermal population, our results show that the chiral putative global minimum strongly dominates at room temperature.

scholarly journals In silico search for planar hexacoordinate Silicon atom: A kinetically viable species

2021 ◽  
Author(s):  
Amlan Kalita ◽  
Shahnaz Rohman ◽  
Chayanika Kashyap ◽  
Sabnam Ullah ◽  
Indrani Baruah ◽  
...  
Keyword(s):  
Silicon Atom ◽  
In Silico ◽  
Density Functional ◽  
Local Minimum ◽  
Global Minimum ◽  
Kinetic Studies ◽  
Coupled Cluster ◽  
Aluminium Atom ◽  
Multiple Bonds ◽  
Functional Theory

In silico search for planar hexacoordinate silicon center has been initiated by global minimum screening with density functional theory and energy refinement using coupled cluster theory. The search resulted in a local minimum of SiAl3Mg3H2+ structure which contains a planar hexacoordinate silicon center (phSi). The phSi structure is 5.8 kcal/mol higher in energy than the global minimum. However, kinetic studies reveal that the local minimum structure has enough stability to be detected experimentally. Born-Oppenheimer molecular dynamics (BOMD) simulations reveal that the phSi structure can be maintained up to 400 K. The formation of multiple bonds between the central silicon atom and framework aluminium atom is the key stabilizing factor for the planar structure.

scholarly journals Exo⇔Endo Isomerism, MEP/DFT, XRD/HSA-Interactions of 2,5-Dimethoxybenzaldehyde: Thermal, 1BNA-Docking, Optical, and TD-DFT Studies

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5970
Author(s):  
Nabil Al-Zaqri ◽  
Mohammed Suleiman ◽  
Anas Al-Ali ◽  
Khaled Alkanad ◽  
Karthik Kumara ◽  
...  
Keyword(s):  
Density Functional ◽  
Energy Gap ◽  
Structural Parameters ◽  
Population Analysis ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
Td Dft

The exo⇔endo isomerization of 2,5-dimethoxybenzaldehyde was theoretically studied by density functional theory (DFT) to examine its favored conformers via sp2–sp2 single rotation. Both isomers were docked against 1BNA DNA to elucidate their binding ability, and the DFT-computed structural parameters results were matched with the X-ray diffraction (XRD) crystallographic parameters. XRD analysis showed that the exo-isomer was structurally favored and was also considered as the kinetically preferred isomer, while several hydrogen-bonding interactions detected in the crystal lattice by XRD were in good agreement with the Hirshfeld surface analysis calculations. The molecular electrostatic potential, Mulliken and natural population analysis charges, frontier molecular orbitals (HOMO/LUMO), and global reactivity descriptors quantum parameters were also determined at the B3LYP/6-311G(d,p) level of theory. The computed electronic calculations, i.e., TD-SCF/DFT, B3LYP-IR, NMR-DB, and GIAO-NMR, were compared to the experimental UV–Vis., optical energy gap, FTIR, and 1H-NMR, respectively. The thermal behavior of 2,5-dimethoxybenzaldehyde was also evaluated in an open atmosphere by a thermogravimetric–derivative thermogravimetric analysis, indicating its stability up to 95 °C.

Global minima and structural properties of Au-Fe nanoalloys from a Mexican Enhanced Genetic Algorithm-based Density Functional Theory

2021 ◽  
pp. 138675
Author(s):  
Manal Abed Mohammed ◽  
Heider A. Abdulhussein ◽  
Muhsen Abood Muhsen Al-ibadi ◽  
Rajesh Kumar Raju ◽  
Roy L. Johnston
Keyword(s):  
Genetic Algorithm ◽  
Density Functional Theory ◽  
Structural Properties ◽  
Density Functional ◽  
Global Minima ◽  
Functional Theory

Theoretical Investigations on Mechanical Stability and Electronic Structure of NbN under Pressures

2011 ◽  
Vol 90-93 ◽  
pp. 1264-1271
Author(s):  
Xiao Feng Li ◽  
Jun Yi Du
Keyword(s):  
Debye Temperature ◽  
Density Functional ◽  
Mechanical Stability ◽  
Structural Parameters ◽  
Theoretical Data ◽  
Hexagonal Structure ◽  
Functional Theory ◽  
Theoretical Investigations ◽  
Crystallographic Structures ◽  
Good Agreement

The ground structure, elastic and electronic properties of several phases of NbN are determined based on ab initio total-energy calculations within the framework of density functional theory. Among the five crystallographic structures that have been investigated, the hexagonal phases have been found to be more stable than the cubic ones. The calculated equilibrium structural parameters are in good agreement with the available experimental results. The elastic constants of five structures in NbN are calculated, which are in consistent with the obtained theoretical and experimental data. The corresponding Debye temperature and elastic ansitropies are also obtained. The Debye temperature of NbN in various structures consistent with available experimental and theoretical data, in which the Debye temperature of δ-NbN is highest. The anisotropies of ZB-NbN, NaCl-NbN, CsCl-NbN gradually increases. For hexagonal structure, the anisotropies of ε-NbN are stronger than that of δ-NbN. The electronic structures of NbN under pressure are investigated. It is found that NbN have metallization and the hybridizations of atoms in NbN under pressure become stronger.

Prediction of Beryllium Clusters from First Principles: Be17 as a Promising New Material for Water Splitting

2021 ◽  
Author(s):  
Behnaz Abyaz ◽  
Zabiollah Mahdavifar ◽  
Georg Schreckenbach ◽  
Yang Gao
Keyword(s):  
Density Functional Theory ◽  
Dft Calculations ◽  
Water Splitting ◽  
First Principles ◽  
Density Functional ◽  
Global Minimum ◽  
Functional Theory ◽  
New Material ◽  
Universal Structure

Evolutionary searches using the USPEX method (Universal Structure Predictor: Evolutionary Xtallography) combined with density functional theory (DFT) calculations were performed to obtain the global minimum structures of beryllium (Ben, n=3-25)...

Research Optical Characteristics of H2S Molecule Adsorption on Agn (n=2,4,6) Clusters

2013 ◽  
Vol 321-324 ◽  
pp. 499-502
Author(s):  
Hong Zhou ◽  
Jun Feng Wang ◽  
Jun Qing Wen ◽  
Wei Bin Cheng ◽  
Jun Fei Wang
Keyword(s):  
Density Functional Theory ◽  
Infrared Spectrum ◽  
Density Functional ◽  
Global Minimum ◽  
Electronic States ◽  
Binding Energies ◽  
Optical Characteristics ◽  
Functional Theory ◽  
Calculation Results ◽  
Planar Geometries

Density-functional theory has been used to calculate the energetically global-minimum geometries and electronic states of AgnH2S (n=2, 4, 6) clusters. The lowest-energy structures of Ag2, Ag4, Ag6, Ag2H2S, Ag4H2S and Ag6H2S clusters were obtained, respectively. The calculation results show that the lowest-energy structures of Ag2, Ag4and Ag6clusters are planar geometries. The binding energies of Agn(n=2, 4, 6) clusters are gradually increasing in our calculations. Compare the infrared spectrum peaks of Ag4cluster with that of Ag6cluster, which show that the peaks shift to shortwave. After adsorption, we found that the peaks shift to shortwave by comparison.

scholarly journals Compression Behavior and Vibrational Properties of New Energetic Material LLM-105 Analyzed Using the Dispersion-Corrected Density Functional Theory

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6831
Author(s):  
Tianming Li ◽  
Junyu Fan ◽  
Zhuoran Wang ◽  
Hanhan Qi ◽  
Yan Su ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Uniaxial Compression ◽  
Density Functional ◽  
Structural Parameters ◽  
Energetic Material ◽  
Structure Stability ◽  
Vibrational Properties ◽  
Detailed Knowledge ◽  
Functional Theory

The 2,6-diamino-3,5-dinitropyrazine-1-oxide (LLM-105) is a newly energetic material with an excellent performance and low sensitivity and has attracted considerable attention. On the basis of the dispersion-corrected density functional theory (DFT-D), the high-pressure responses of vibrational properties, in conjunction with structural properties, are used to understand its intermolecular interactions and anisotropic properties under hydrostatic and uniaxial compressions. At ambient and pressure conditions, the DFT-D scheme could reasonably describe the structural parameters of LLM-105. The hydrogen bond network, resembling a parallelogram shape, links two adjacent molecules and contributes to the structure stability under hydrostatic compression. The anisotropy of LLM-105 is pronounced, especially for Raman spectra under uniaxial compression. Specifically, the red-shifts of modes are obtained for [100] and [010] compressions, which are caused by the pressure-induced enhance of the strength of the hydrogen bonds. Importantly, coupling modes and discontinuous Raman shifts are observed along [010] and [001] compressions, which are related to the intramolecular vibrational redistribution and possible structural transformations under uniaxial compressions. Overall, the detailed knowledge of the high-pressure responses of LLM-105 is established from the atomistic level. Uniaxial compression responses provide useful insights for realistic shock conditions.

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