scholarly journals Density Functional Theory Study on the Surface Properties and Floatability of Hemimorphite and Smithsonite

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 542 ◽  
Author(s):  
Cong Han ◽  
Tingting Li ◽  
Wei Zhang ◽  
Hao Zhang ◽  
Sikai Zhao ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Surface Properties ◽  
Density Functional ◽  
Orbital Energy ◽  
Mulliken Population ◽  
Functional Theory ◽  
Flotation Process ◽  
First Principle Calculation ◽  
Calculation Results ◽  
Core Issues

Hemimorphite and smithsonite are all-important zinc oxide minerals. The beneficiation and separation of them using flotation method is usually considered difficultly. Minerals surface wettability and its regulation are the core issues in the flotation process, which closely correlate with the surface properties of the minerals. Therefore, an in-depth understanding of the surface properties of the two minerals is of great significance for the study of the flotation technology of them. In this study, the surface properties of the hemimorphite (110) surface and the simthsointe (101) surface, and their relationships to the mineral floatability have been investigated by first-principle calculation method based on density functional theory. The calculation results demonstrated that the hemimorphite (110) surface exhibited more obviously surface reconstruction. For the orbital energy level of the surface atoms of two minerals, the O 2p orbital is closer to the Fermi level than the Zn 3d. Chemical bond Mulliken population value indicated that the ionicity of the unsaturated linkage on the smithsonite (101) surface was stronger than that on the hemimorphite (110) surface. The absolute values of the ratios of negative charges to positive charges on the surfaces of hemimorphite and smithsonite were 1.529 and 1.256 respectively. These results implied that the O atoms on hemimorphite (110) surface are more impede collector molecule, such as hydroximic acid, bond with Zn atom, hemimorphite (110) surface is more readily wetted by water. This study provides comprehension at an atomic level to the relationship between surface properties and the floatability of hemimorphite and smithsonite.

On the Nature of Halide-Water Interactions: Insights from Many-Body Representations and Density Functional Theory

2019 ◽  
Author(s):  
Brandon B. Bizzarro ◽  
Colin K. Egan ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Charge Transfer ◽  
Molecular Orbital ◽  
Density Functional ◽  
Decomposition Analysis ◽  
Orbital Energy ◽  
Energy Decomposition Analysis ◽  
Interaction Energies ◽  
Many Body ◽  
Functional Theory

<div> <div> <div> <p>Interaction energies of halide-water dimers, X<sup>-</sup>(H<sub>2</sub>O), and trimers, X<sup>-</sup>(H<sub>2</sub>O)<sub>2</sub>, with X = F, Cl, Br, and I, are investigated using various many-body models and exchange-correlation functionals selected across the hierarchy of density functional theory (DFT) approximations. Analysis of the results obtained with the many-body models demonstrates the need to capture important short-range interactions in the regime of large inter-molecular orbital overlap, such as charge transfer and charge penetration. Failure to reproduce these effects can lead to large deviations relative to reference data calculated at the coupled cluster level of theory. Decompositions of interaction energies carried out with the absolutely localized molecular orbital energy decomposition analysis (ALMO-EDA) method demonstrate that permanent and inductive electrostatic energies are accurately reproduced by all classes of XC functionals (from generalized gradient corrected (GGA) to hybrid and range-separated functionals), while significant variance is found for charge transfer energies predicted by different XC functionals. Since GGA and hybrid XC functionals predict the most and least attractive charge transfer energies, respectively, the large variance is likely due to the delocalization error. In this scenario, the hybrid XC functionals are then expected to provide the most accurate charge transfer energies. The sum of Pauli repulsion and dispersion energies are the most varied among the XC functionals, but it is found that a correspondence between the interaction energy and the ALMO EDA total frozen energy may be used to determine accurate estimates for these contributions. </p> </div> </div> </div>

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.

Insights from Density Functional Theory Calculations into the Effects of the Adsorption and Dissociation of Water on the Surface Properties of Zinc Diphosphide (ZnP2) Nanocrystals

2021 ◽  
Author(s):  
Barbara Farkas ◽  
Aleksandar Zivkovic ◽  
Veikko Uahengo ◽  
Nelson Yaw Dzade ◽  
Nora Henriette De Leeuw
Keyword(s):  
Density Functional Theory ◽  
Surface Structure ◽  
Surface Properties ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Photovoltaic Applications ◽  
Zinc Diphosphide ◽  
Adsorption And Dissociation

Zinc phosphides (ZnP2 and Zn3P2) are emerging absorber materials for photovoltaic applications owing to their abundancy and non-toxic nature. Herein, we provide a comprehensive characterisation of the surface structure, composition,...

Bisoxazoline–copper(I)-catalyzed aziridination of diazoacetate with imines — A DFT study

2010 ◽  
Vol 88 (10) ◽  
pp. 981-990 ◽  
Author(s):  
Qingxi Meng ◽  
Fen Wang ◽  
Ming Li
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Mode I ◽  
Mode Ii ◽  
Free Energies ◽  
Functional Theory ◽  
Carboxylate Complex ◽  
Calculation Results ◽  
Favorable Reaction ◽  
Level Calculation

Density functional theory (DFT) has been used to study bisoxazoline–copper(I)-catalyzed aziridination of diazoacetate with syn-imines or anti-imines. All the intermediates and transition states were optimized completely at the B3LYP/6-31G(d) level. Calculation results confirm that Cu(I)-catalyzed aziridination goes mainly through the catalyst–diazoacetate complex (M1), the copper(I)–carbene intermediate (M2), the copper–carbene–imine complex (M3), and the catalyst–aziridine carboxylate complex (M4). For syn-imines, the reaction mode I (C3–N5 bond attacking the Cu–C1 bond of M2) is more dominant than the reaction mode II (C3–N5 bond attacking the carbene–carbon C1 of M2), and the attack from the si-surface of M2 is prior to the re-surface. For anti-imines, the reaction modes and attacks from the si- or re-surface coexist. The reactivity of syn-imines is stronger than anti-imines. The favorable reaction channel is CA2 → M1b → TS1b → M2 → syn-TS2b → syn-M3b → syn-TS3b → syn-M4b → syn-P2. The dominant product theoretically predicted is of (S,S)-chirality. On the whole, the solvent effect decreases the free energies of the species.

Design and characteration of planar star-shaped oligomer electron donors for organic solar cells: a DFT study

2015 ◽  
Vol 93 (11) ◽  
pp. 1181-1190 ◽  
Author(s):  
Dongmei Wang ◽  
Zhiyuan Geng
Keyword(s):  
Density Functional Theory ◽  
Solar Cells ◽  
Charge Transfer ◽  
Energy Level ◽  
Organic Solar Cells ◽  
Density Functional ◽  
Short Circuit ◽  
Frontier Molecular Orbital ◽  
Orbital Energy ◽  
Functional Theory

To seek high-performance oligomer donor materials used in organic solar cells, four star-shaped molecules with a planar donor core derived from the recent reported molecule 3T-P-DPP (phenyl-1,3,5-trithienyl-diketopyrrolopyrrole) were designed. The molecular properties affecting the cell performance, such as structural characteristics, frontier molecular orbital energy level, absorption spectra, exciton character, and charge transfer/transport, were investigated by means of the density functional theory and time-dependent density functional theory methods. Comparative analysis showed that the new designed molecule 3 with a TTT (2,4,6-tri(thiophen-2-yl)-1,3,5-triazine) core has better planarity, a lower HOMO energy level, and a higher absorption efficiency, as well as more favorable exciton dissociation and charge transfer than the others, potentially improving the open-circuit voltage and short-circuit current density. Consequently, 3 maybe superior to 3T-P-DPP and may act as a promising donor material candidate for organic solar cells.

Research with KNbO 3 Bulk and Surface Properties Based on Density Functional Theory

2013 ◽  
Vol 30 (2) ◽  
pp. 027302 ◽  
Author(s):  
Hong-Guo Sun ◽  
Zhong-Xiang Zhou ◽  
Cheng-Xun Yuan ◽  
Xiao-Niu Yang
Keyword(s):  
Density Functional Theory ◽  
Surface Properties ◽  
Density Functional ◽  
Functional Theory

scholarly journals The Interaction of Air Pollutant Molecules with Germanene and Silicene: a Density Functional Theory Study

Molekul ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. 92
Author(s):  
Muhammad Rifqi Al Fauzan ◽  
Wijayanti Dwi Astuti ◽  
Ghorby Al Fauzan ◽  
Sholihun Sholihun
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Adsorption Process ◽  
Air Pollutant ◽  
Atmospheric Pollutants ◽  
Mulliken Charge ◽  
Density Functional Theory Study ◽  
Functional Theory ◽  
Calculation Results ◽  
Adsorbent Materials

We investigate the adsorption of atmospheric pollutants on germanene and silicene using density functional theory (DFT) calculations. In this study, we use carbon monoxide (CO) and nitric oxide (NO) as the pollutant molecules. Electronic properties of germanene and silicene are explored to obtain a good understanding in the adsorption process. Our calculation results show both germanene and silicene provide an identical mechanism of adsorption. Germanene and silicene adsorb CO and NO spontaneously with physisorption and chemisorption types for CO and NO molecules, respectively. We also conduct the Mulliken charges calculations to evaluate the transformation of atomic charges due to the adsorption process. From Mulliken charge calculation results we can confirm the existence of charge transfer between the adsorbent materials and the pollutant molecules. This phenomenon lies behind the occurrence of the adsorption process.

scholarly journals Synthesis and Density Functional Theory Analysis of Pyrazole Integrated Pyrimidinetrione

2019 ◽  
Vol 9 (1S3) ◽  
pp. 283-288
Keyword(s):  
Density Functional Theory ◽  
Nmr Spectroscopy ◽  
Density Functional ◽  
Geometry Optimization ◽  
Analytical Techniques ◽  
Theory Analysis ◽  
Mulliken Population ◽  
Functional Theory ◽  
Ir And Nmr Spectroscopy

A pyrazole integrated pyrimidinetrione 6 has been synthesized and its structure has been established employing physical and analytical techniques such as IR and NMR spectroscopy. Further, density functional theory studies such as geometry optimization, FMOs, MEP, Mulliken population and NLO analyses of the synthesized compound 6 have been carried out using DFT – B3LYP [6-311++G(d,p)] method and the results obtained have been discussed.

Sign in / Sign up

Export Citation Format

Share Document