scholarly journals Integrating Density Functional Theory Modeling with Experimental Data to Understand and Predict Sorption Reactions: Exchange of Salicylate for Phosphate on Goethite

Soil Systems ◽  
2020 ◽  
Vol 4 (2) ◽  
pp. 27 ◽  
Author(s):  
James D. Kubicki ◽  
Tsutomu Ohno

Density functional theory (DFT) calculations are a quantum mechanical approach that can be used to model chemical reactions on an atomistic scale. DFT provides predictions on structures, thermodynamics, spectroscopic parameters and kinetics that can be compared against experimentally determined data. This paper is a primer on the basics of utilizing DFT for applications in mineral-water interfaces. In our case-study, we use DFT to model the surface complexes of phosphate and salicylate adsorbed onto the (101) and (210) surfaces of α-FeOOH (goethite), as an example of combining DFT and experiment. These three components are important in the phosphorus-organic matter interactions in soils, and by comparing the energies of the two surface complexes, the exchange energy of salicylate for phosphate onto goethite can be estimated. The structures of the surface complexes are predicted and the resulting vibrational frequencies calculated based on these structures are compared to previous observations. Upon verification of reasonable surface complex models, the potential energy of exchanging salicylate for phosphate is calculated and shown to be significantly exothermic. This model result is consistent with observations of plant exudates, such as salicylate freeing adsorbed phosphate in soils under P-limited conditions.

Energies ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2587
Author(s):  
Shuo Liu ◽  
Yuguo Wu ◽  
Chunshan Zhou ◽  
Jianming Wu ◽  
Yulong Zhang

The CO formation rules of coal were analyzed by a self-developed testing device under ambient temperature. The changes of functional groups caused by oxidation were obtained using Fourier-transform infrared spectroscopy (FTIR). The experimental results showed that CO was generated during the ambient temperature oxidation. The highest concentration level of CO could be 389 ppm. The methylene and aldehyde groups on the side chains were involved in the reaction. For the quantum mechanical approach, we employed the density functional theory with the 6–31 G (d, p) basis set. Density functional theory–based computations interpreted the possible reaction sites on a coal molecule by electronic static potential analysis. The rationality of the predicted reactions was also evaluated by transition state analysis and energy analysis. This research theoretically proved that coal could be oxidized to carbon monoxide under ambient temperatures and gave the possible reaction paths.


2020 ◽  
Vol 22 (28) ◽  
pp. 15805-15830 ◽  
Author(s):  
Dale R. Lonsdale ◽  
Lars Goerigk

The one-electron self-interaction error (SIE) is analysed for 74 Density Functional Theory (DFT) approximations in a series of novel one-electron model systems revealing new aspects of the SIE that should be considered in future DFT developments.


RSC Advances ◽  
2016 ◽  
Vol 6 (103) ◽  
pp. 101216-101225 ◽  
Author(s):  
Renan Augusto Pontes Ribeiro ◽  
Sergio Ricardo de Lazaro ◽  
Carlo Gatti

In this study, ab initio density functional theory calculations were performed on ATiO3 (A = Mn, Fe, Ni) materials for multiferroic applications.


2021 ◽  
Vol 19 (50) ◽  
pp. 70-76
Author(s):  
Mohsin Al-Khaykanee ◽  
Ali Al-Jawdahb

The present work shows a theoretical results that have been used the functional Hybrid of three parameters Lee-Yang-Parr (B3LYP) of the quantum mechanical approach for density functional theory with (Spanish Initiative for Electronic Simulations with Thousands of Atoms) SIESTA code. All calculations were carried out employing the used method at the Gaussian 09 package of programs. It was reported the main point for research on dominance of the bandgap of elongated pi-conjugated molecules by using different chemical groups replacing hydrogen atom in the most molecules that used in this work. The side groups creates another factor that controls the value of the band gap. The dihedral angle between the two phenyl rings plays more important role in controlling the band gap in these molecules.


2021 ◽  
Author(s):  
Thayalaraj Christopher Jeyakumar ◽  
Francisxavier Paularokiadoss

The chemistry of Group 13 Monohalide is of great interest due to its isoelectronic relationship with carbon monoxide and dinitrogen. In recent years, theoretical and experimental studies have been evolved on the group-13 atom-based diatomic molecules as a ligand. The synthetic, characterisation and reactivity of various metal complexes have been well discussed in recent reviews. The nature of the metal bonding of these ligands of various types has been explained in addition by the variety of theoretical studies (using DFT methods) such as FMO and EDA. This chapter has a comprehensive experimental and theoretical study of group 13 monohalides as a ligand in coordination chemistry.


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