Effect of Basicity on the Hydrolysis of the Bi(III) Aqua Ion in Solution: An Ab Initio Molecular Dynamics Study

2018 ◽  
Vol 122 (7) ◽  
pp. 1905-1915 ◽  
Author(s):  
Regla Ayala ◽  
José Manuel Martínez ◽  
Rafael R. Pappalardo ◽  
Keith Refson ◽  
Enrique Sánchez Marcos
2010 ◽  
Vol 114 (40) ◽  
pp. 12866-12874 ◽  
Author(s):  
Regla Ayala ◽  
Riccardo Spezia ◽  
Rodolphe Vuilleumier ◽  
José Manuel Martínez ◽  
Rafael R. Pappalardo ◽  
...  

2019 ◽  
Vol 5 (6) ◽  
pp. eaav6503 ◽  
Author(s):  
Laura M. McCaslin ◽  
Mark A. Johnson ◽  
R. Benny Gerber

SN2-type halide substitution and hydrolysis are two of the most ubiquitous reactions in chemistry. The interplay between these processes is fundamental in atmospheric chemistry through reactions of N2O5 and seawater. N2O5 plays a major role in regulating levels of O3, OH, NOx, and CH4. While the reactions of N2O5 and seawater are of central importance, little is known about their mechanisms. Of interest is the activation of Cl in seawater by the formation of gaseous ClNO2, which occurs despite the fact that hydrolysis (to HNO3) is energetically more favorable. We determine key features of the reaction landscape that account for this behavior in a theoretical study of the cluster N2O5/Cl−/H2O. This was carried out using ab initio molecular dynamics to determine reaction pathways, structures, and time scales. While hydrolysis of N2O5 occurs in the absence of Cl−, results here reveal that a low-lying pathway featuring halide substitution intermediates enhances hydrolysis.


2019 ◽  
Author(s):  
Liqun Cao ◽  
Jinzhe Zeng ◽  
Mingyuan Xu ◽  
Chih-Hao Chin ◽  
Tong Zhu ◽  
...  

Combustion is a kind of important reaction that affects people's daily lives and the development of aerospace. Exploring the reaction mechanism contributes to the understanding of combustion and the more efficient use of fuels. Ab initio quantum mechanical (QM) calculation is precise but limited by its computational time for large-scale systems. In order to carry out reactive molecular dynamics (MD) simulation for combustion accurately and quickly, we develop the MFCC-combustion method in this study, which calculates the interaction between atoms using QM method at the level of MN15/6-31G(d). Each molecule in systems is treated as a fragment, and when the distance between any two atoms in different molecules is greater than 3.5 Å, a new fragment involved two molecules is produced in order to consider the two-body interaction. The deviations of MFCC-combustion from full system calculations are within a few kcal/mol, and the result clearly shows that the calculated energies of the different systems using MFCC-combustion are close to converging after the distance thresholds are larger than 3.5 Å for the two-body QM interactions. The methane combustion was studied with the MFCC-combustion method to explore the combustion mechanism of the methane-oxygen system.


2021 ◽  
Vol 22 (9) ◽  
pp. 4378
Author(s):  
Anna Helena Mazurek ◽  
Łukasz Szeleszczuk ◽  
Dariusz Maciej Pisklak

This review focuses on a combination of ab initio molecular dynamics (aiMD) and NMR parameters calculations using quantum mechanical methods. The advantages of such an approach in comparison to the commonly applied computations for the structures optimized at 0 K are presented. This article was designed as a convenient overview of the applied parameters such as the aiMD type, DFT functional, time step, or total simulation time, as well as examples of previously studied systems. From the analysis of the published works describing the applications of such combinations, it was concluded that including fast, small-amplitude motions through aiMD has a noticeable effect on the accuracy of NMR parameters calculations.


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